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Diffstat (limited to 'src/com/android/launcher3/PagedView.java')
| -rw-r--r-- | src/com/android/launcher3/PagedView.java | 1981 |
1 files changed, 1981 insertions, 0 deletions
diff --git a/src/com/android/launcher3/PagedView.java b/src/com/android/launcher3/PagedView.java new file mode 100644 index 000000000..8716a33be --- /dev/null +++ b/src/com/android/launcher3/PagedView.java @@ -0,0 +1,1981 @@ +/* + * Copyright (C) 2010 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package com.android.launcher3; + +import android.animation.Animator; +import android.animation.AnimatorListenerAdapter; +import android.animation.ValueAnimator; +import android.content.Context; +import android.content.res.TypedArray; +import android.graphics.Canvas; +import android.graphics.Rect; +import android.os.Bundle; +import android.os.Parcel; +import android.os.Parcelable; +import android.util.AttributeSet; +import android.util.Log; +import android.view.InputDevice; +import android.view.KeyEvent; +import android.view.MotionEvent; +import android.view.VelocityTracker; +import android.view.View; +import android.view.ViewConfiguration; +import android.view.ViewGroup; +import android.view.ViewParent; +import android.view.accessibility.AccessibilityEvent; +import android.view.accessibility.AccessibilityManager; +import android.view.accessibility.AccessibilityNodeInfo; +import android.view.animation.Interpolator; +import android.widget.Scroller; + +import com.android.launcher3.R; + +import java.util.ArrayList; + +/** + * An abstraction of the original Workspace which supports browsing through a + * sequential list of "pages" + */ +public abstract class PagedView extends ViewGroup implements ViewGroup.OnHierarchyChangeListener { + private static final String TAG = "PagedView"; + private static final boolean DEBUG = false; + protected static final int INVALID_PAGE = -1; + + // the min drag distance for a fling to register, to prevent random page shifts + private static final int MIN_LENGTH_FOR_FLING = 25; + + protected static final int PAGE_SNAP_ANIMATION_DURATION = 550; + protected static final int MAX_PAGE_SNAP_DURATION = 750; + protected static final int SLOW_PAGE_SNAP_ANIMATION_DURATION = 950; + protected static final float NANOTIME_DIV = 1000000000.0f; + + private static final float OVERSCROLL_ACCELERATE_FACTOR = 2; + private static final float OVERSCROLL_DAMP_FACTOR = 0.14f; + + private static final float RETURN_TO_ORIGINAL_PAGE_THRESHOLD = 0.33f; + // The page is moved more than halfway, automatically move to the next page on touch up. + private static final float SIGNIFICANT_MOVE_THRESHOLD = 0.4f; + + // The following constants need to be scaled based on density. The scaled versions will be + // assigned to the corresponding member variables below. + private static final int FLING_THRESHOLD_VELOCITY = 500; + private static final int MIN_SNAP_VELOCITY = 1500; + private static final int MIN_FLING_VELOCITY = 250; + + static final int AUTOMATIC_PAGE_SPACING = -1; + + protected int mFlingThresholdVelocity; + protected int mMinFlingVelocity; + protected int mMinSnapVelocity; + + protected float mDensity; + protected float mSmoothingTime; + protected float mTouchX; + + protected boolean mFirstLayout = true; + + protected int mCurrentPage; + protected int mNextPage = INVALID_PAGE; + protected int mMaxScrollX; + protected Scroller mScroller; + private VelocityTracker mVelocityTracker; + + private float mDownMotionX; + protected float mLastMotionX; + protected float mLastMotionXRemainder; + protected float mLastMotionY; + protected float mTotalMotionX; + private int mLastScreenCenter = -1; + private int[] mChildOffsets; + private int[] mChildRelativeOffsets; + private int[] mChildOffsetsWithLayoutScale; + + protected final static int TOUCH_STATE_REST = 0; + protected final static int TOUCH_STATE_SCROLLING = 1; + protected final static int TOUCH_STATE_PREV_PAGE = 2; + protected final static int TOUCH_STATE_NEXT_PAGE = 3; + protected final static float ALPHA_QUANTIZE_LEVEL = 0.0001f; + + protected int mTouchState = TOUCH_STATE_REST; + protected boolean mForceScreenScrolled = false; + + protected OnLongClickListener mLongClickListener; + + protected boolean mAllowLongPress = true; + + protected int mTouchSlop; + private int mPagingTouchSlop; + private int mMaximumVelocity; + private int mMinimumWidth; + protected int mPageSpacing; + protected int mPageLayoutPaddingTop; + protected int mPageLayoutPaddingBottom; + protected int mPageLayoutPaddingLeft; + protected int mPageLayoutPaddingRight; + protected int mPageLayoutWidthGap; + protected int mPageLayoutHeightGap; + protected int mCellCountX = 0; + protected int mCellCountY = 0; + protected boolean mCenterPagesVertically; + protected boolean mAllowOverScroll = true; + protected int mUnboundedScrollX; + protected int[] mTempVisiblePagesRange = new int[2]; + protected boolean mForceDrawAllChildrenNextFrame; + + // mOverScrollX is equal to getScrollX() when we're within the normal scroll range. Otherwise + // it is equal to the scaled overscroll position. We use a separate value so as to prevent + // the screens from continuing to translate beyond the normal bounds. + protected int mOverScrollX; + + // parameter that adjusts the layout to be optimized for pages with that scale factor + protected float mLayoutScale = 1.0f; + + protected static final int INVALID_POINTER = -1; + + protected int mActivePointerId = INVALID_POINTER; + + private PageSwitchListener mPageSwitchListener; + + protected ArrayList<Boolean> mDirtyPageContent; + + // If true, syncPages and syncPageItems will be called to refresh pages + protected boolean mContentIsRefreshable = true; + + // If true, modify alpha of neighboring pages as user scrolls left/right + protected boolean mFadeInAdjacentScreens = true; + + // It true, use a different slop parameter (pagingTouchSlop = 2 * touchSlop) for deciding + // to switch to a new page + protected boolean mUsePagingTouchSlop = true; + + // If true, the subclass should directly update scrollX itself in its computeScroll method + // (SmoothPagedView does this) + protected boolean mDeferScrollUpdate = false; + + protected boolean mIsPageMoving = false; + + // All syncs and layout passes are deferred until data is ready. + protected boolean mIsDataReady = false; + + // Scrolling indicator + private ValueAnimator mScrollIndicatorAnimator; + private View mScrollIndicator; + private int mScrollIndicatorPaddingLeft; + private int mScrollIndicatorPaddingRight; + private boolean mHasScrollIndicator = true; + private boolean mShouldShowScrollIndicator = false; + private boolean mShouldShowScrollIndicatorImmediately = false; + protected static final int sScrollIndicatorFadeInDuration = 150; + protected static final int sScrollIndicatorFadeOutDuration = 650; + protected static final int sScrollIndicatorFlashDuration = 650; + private boolean mScrollingPaused = false; + + // If set, will defer loading associated pages until the scrolling settles + private boolean mDeferLoadAssociatedPagesUntilScrollCompletes; + + public interface PageSwitchListener { + void onPageSwitch(View newPage, int newPageIndex); + } + + public PagedView(Context context) { + this(context, null); + } + + public PagedView(Context context, AttributeSet attrs) { + this(context, attrs, 0); + } + + public PagedView(Context context, AttributeSet attrs, int defStyle) { + super(context, attrs, defStyle); + + TypedArray a = context.obtainStyledAttributes(attrs, + R.styleable.PagedView, defStyle, 0); + setPageSpacing(a.getDimensionPixelSize(R.styleable.PagedView_pageSpacing, 0)); + mPageLayoutPaddingTop = a.getDimensionPixelSize( + R.styleable.PagedView_pageLayoutPaddingTop, 0); + mPageLayoutPaddingBottom = a.getDimensionPixelSize( + R.styleable.PagedView_pageLayoutPaddingBottom, 0); + mPageLayoutPaddingLeft = a.getDimensionPixelSize( + R.styleable.PagedView_pageLayoutPaddingLeft, 0); + mPageLayoutPaddingRight = a.getDimensionPixelSize( + R.styleable.PagedView_pageLayoutPaddingRight, 0); + mPageLayoutWidthGap = a.getDimensionPixelSize( + R.styleable.PagedView_pageLayoutWidthGap, 0); + mPageLayoutHeightGap = a.getDimensionPixelSize( + R.styleable.PagedView_pageLayoutHeightGap, 0); + mScrollIndicatorPaddingLeft = + a.getDimensionPixelSize(R.styleable.PagedView_scrollIndicatorPaddingLeft, 0); + mScrollIndicatorPaddingRight = + a.getDimensionPixelSize(R.styleable.PagedView_scrollIndicatorPaddingRight, 0); + a.recycle(); + + setHapticFeedbackEnabled(false); + init(); + } + + /** + * Initializes various states for this workspace. + */ + protected void init() { + mDirtyPageContent = new ArrayList<Boolean>(); + mDirtyPageContent.ensureCapacity(32); + mScroller = new Scroller(getContext(), new ScrollInterpolator()); + mCurrentPage = 0; + mCenterPagesVertically = true; + + final ViewConfiguration configuration = ViewConfiguration.get(getContext()); + mTouchSlop = configuration.getScaledTouchSlop(); + mPagingTouchSlop = configuration.getScaledPagingTouchSlop(); + mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); + mDensity = getResources().getDisplayMetrics().density; + + mFlingThresholdVelocity = (int) (FLING_THRESHOLD_VELOCITY * mDensity); + mMinFlingVelocity = (int) (MIN_FLING_VELOCITY * mDensity); + mMinSnapVelocity = (int) (MIN_SNAP_VELOCITY * mDensity); + setOnHierarchyChangeListener(this); + } + + public void setPageSwitchListener(PageSwitchListener pageSwitchListener) { + mPageSwitchListener = pageSwitchListener; + if (mPageSwitchListener != null) { + mPageSwitchListener.onPageSwitch(getPageAt(mCurrentPage), mCurrentPage); + } + } + + /** + * Note: this is a reimplementation of View.isLayoutRtl() since that is currently hidden api. + */ + public boolean isLayoutRtl() { + return (getLayoutDirection() == LAYOUT_DIRECTION_RTL); + } + + /** + * Called by subclasses to mark that data is ready, and that we can begin loading and laying + * out pages. + */ + protected void setDataIsReady() { + mIsDataReady = true; + } + protected boolean isDataReady() { + return mIsDataReady; + } + + /** + * Returns the index of the currently displayed page. + * + * @return The index of the currently displayed page. + */ + int getCurrentPage() { + return mCurrentPage; + } + int getNextPage() { + return (mNextPage != INVALID_PAGE) ? mNextPage : mCurrentPage; + } + + int getPageCount() { + return getChildCount(); + } + + View getPageAt(int index) { + return getChildAt(index); + } + + protected int indexToPage(int index) { + return index; + } + + /** + * Updates the scroll of the current page immediately to its final scroll position. We use this + * in CustomizePagedView to allow tabs to share the same PagedView while resetting the scroll of + * the previous tab page. + */ + protected void updateCurrentPageScroll() { + // If the current page is invalid, just reset the scroll position to zero + int newX = 0; + if (0 <= mCurrentPage && mCurrentPage < getPageCount()) { + int offset = getChildOffset(mCurrentPage); + int relOffset = getRelativeChildOffset(mCurrentPage); + newX = offset - relOffset; + } + scrollTo(newX, 0); + mScroller.setFinalX(newX); + mScroller.forceFinished(true); + } + + /** + * Called during AllApps/Home transitions to avoid unnecessary work. When that other animation + * ends, {@link #resumeScrolling()} should be called, along with + * {@link #updateCurrentPageScroll()} to correctly set the final state and re-enable scrolling. + */ + void pauseScrolling() { + mScroller.forceFinished(true); + cancelScrollingIndicatorAnimations(); + mScrollingPaused = true; + } + + /** + * Enables scrolling again. + * @see #pauseScrolling() + */ + void resumeScrolling() { + mScrollingPaused = false; + } + /** + * Sets the current page. + */ + void setCurrentPage(int currentPage) { + if (!mScroller.isFinished()) { + mScroller.abortAnimation(); + } + // don't introduce any checks like mCurrentPage == currentPage here-- if we change the + // the default + if (getChildCount() == 0) { + return; + } + + + mCurrentPage = Math.max(0, Math.min(currentPage, getPageCount() - 1)); + updateCurrentPageScroll(); + updateScrollingIndicator(); + notifyPageSwitchListener(); + invalidate(); + } + + protected void notifyPageSwitchListener() { + if (mPageSwitchListener != null) { + mPageSwitchListener.onPageSwitch(getPageAt(mCurrentPage), mCurrentPage); + } + } + + protected void pageBeginMoving() { + if (!mIsPageMoving) { + mIsPageMoving = true; + onPageBeginMoving(); + } + } + + protected void pageEndMoving() { + if (mIsPageMoving) { + mIsPageMoving = false; + onPageEndMoving(); + } + } + + protected boolean isPageMoving() { + return mIsPageMoving; + } + + // a method that subclasses can override to add behavior + protected void onPageBeginMoving() { + } + + // a method that subclasses can override to add behavior + protected void onPageEndMoving() { + } + + /** + * Registers the specified listener on each page contained in this workspace. + * + * @param l The listener used to respond to long clicks. + */ + @Override + public void setOnLongClickListener(OnLongClickListener l) { + mLongClickListener = l; + final int count = getPageCount(); + for (int i = 0; i < count; i++) { + getPageAt(i).setOnLongClickListener(l); + } + } + + @Override + public void scrollBy(int x, int y) { + scrollTo(mUnboundedScrollX + x, getScrollY() + y); + } + + @Override + public void scrollTo(int x, int y) { + final boolean isRtl = isLayoutRtl(); + mUnboundedScrollX = x; + + boolean isXBeforeFirstPage = isRtl ? (x > mMaxScrollX) : (x < 0); + boolean isXAfterLastPage = isRtl ? (x < 0) : (x > mMaxScrollX); + if (isXBeforeFirstPage) { + super.scrollTo(0, y); + if (mAllowOverScroll) { + if (isRtl) { + overScroll(x - mMaxScrollX); + } else { + overScroll(x); + } + } + } else if (isXAfterLastPage) { + super.scrollTo(mMaxScrollX, y); + if (mAllowOverScroll) { + if (isRtl) { + overScroll(x); + } else { + overScroll(x - mMaxScrollX); + } + } + } else { + mOverScrollX = x; + super.scrollTo(x, y); + } + + mTouchX = x; + mSmoothingTime = System.nanoTime() / NANOTIME_DIV; + } + + // we moved this functionality to a helper function so SmoothPagedView can reuse it + protected boolean computeScrollHelper() { + if (mScroller.computeScrollOffset()) { + // Don't bother scrolling if the page does not need to be moved + if (getScrollX() != mScroller.getCurrX() + || getScrollY() != mScroller.getCurrY() + || mOverScrollX != mScroller.getCurrX()) { + scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); + } + invalidate(); + return true; + } else if (mNextPage != INVALID_PAGE) { + mCurrentPage = Math.max(0, Math.min(mNextPage, getPageCount() - 1)); + mNextPage = INVALID_PAGE; + notifyPageSwitchListener(); + + // Load the associated pages if necessary + if (mDeferLoadAssociatedPagesUntilScrollCompletes) { + loadAssociatedPages(mCurrentPage); + mDeferLoadAssociatedPagesUntilScrollCompletes = false; + } + + // We don't want to trigger a page end moving unless the page has settled + // and the user has stopped scrolling + if (mTouchState == TOUCH_STATE_REST) { + pageEndMoving(); + } + + // Notify the user when the page changes + AccessibilityManager accessibilityManager = (AccessibilityManager) + getContext().getSystemService(Context.ACCESSIBILITY_SERVICE); + if (accessibilityManager.isEnabled()) { + AccessibilityEvent ev = + AccessibilityEvent.obtain(AccessibilityEvent.TYPE_VIEW_SCROLLED); + ev.getText().add(getCurrentPageDescription()); + sendAccessibilityEventUnchecked(ev); + } + return true; + } + return false; + } + + @Override + public void computeScroll() { + computeScrollHelper(); + } + + @Override + protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { + if (!mIsDataReady) { + super.onMeasure(widthMeasureSpec, heightMeasureSpec); + return; + } + + final int widthMode = MeasureSpec.getMode(widthMeasureSpec); + final int widthSize = MeasureSpec.getSize(widthMeasureSpec); + final int heightMode = MeasureSpec.getMode(heightMeasureSpec); + int heightSize = MeasureSpec.getSize(heightMeasureSpec); + if (widthMode != MeasureSpec.EXACTLY) { + throw new IllegalStateException("Workspace can only be used in EXACTLY mode."); + } + + // Return early if we aren't given a proper dimension + if (widthSize <= 0 || heightSize <= 0) { + super.onMeasure(widthMeasureSpec, heightMeasureSpec); + return; + } + + /* Allow the height to be set as WRAP_CONTENT. This allows the particular case + * of the All apps view on XLarge displays to not take up more space then it needs. Width + * is still not allowed to be set as WRAP_CONTENT since many parts of the code expect + * each page to have the same width. + */ + int maxChildHeight = 0; + + final int verticalPadding = getPaddingTop() + getPaddingBottom(); + final int horizontalPadding = getPaddingLeft() + getPaddingRight(); + + + // The children are given the same width and height as the workspace + // unless they were set to WRAP_CONTENT + if (DEBUG) Log.d(TAG, "PagedView.onMeasure(): " + widthSize + ", " + heightSize); + final int childCount = getChildCount(); + for (int i = 0; i < childCount; i++) { + // disallowing padding in paged view (just pass 0) + final View child = getPageAt(i); + final LayoutParams lp = (LayoutParams) child.getLayoutParams(); + + int childWidthMode; + if (lp.width == LayoutParams.WRAP_CONTENT) { + childWidthMode = MeasureSpec.AT_MOST; + } else { + childWidthMode = MeasureSpec.EXACTLY; + } + + int childHeightMode; + if (lp.height == LayoutParams.WRAP_CONTENT) { + childHeightMode = MeasureSpec.AT_MOST; + } else { + childHeightMode = MeasureSpec.EXACTLY; + } + + final int childWidthMeasureSpec = + MeasureSpec.makeMeasureSpec(widthSize - horizontalPadding, childWidthMode); + final int childHeightMeasureSpec = + MeasureSpec.makeMeasureSpec(heightSize - verticalPadding, childHeightMode); + + child.measure(childWidthMeasureSpec, childHeightMeasureSpec); + maxChildHeight = Math.max(maxChildHeight, child.getMeasuredHeight()); + if (DEBUG) Log.d(TAG, "\tmeasure-child" + i + ": " + child.getMeasuredWidth() + ", " + + child.getMeasuredHeight()); + } + + if (heightMode == MeasureSpec.AT_MOST) { + heightSize = maxChildHeight + verticalPadding; + } + + setMeasuredDimension(widthSize, heightSize); + + // We can't call getChildOffset/getRelativeChildOffset until we set the measured dimensions. + // We also wait until we set the measured dimensions before flushing the cache as well, to + // ensure that the cache is filled with good values. + invalidateCachedOffsets(); + + if (childCount > 0) { + if (DEBUG) Log.d(TAG, "getRelativeChildOffset(): " + getMeasuredWidth() + ", " + + getChildWidth(0)); + + // Calculate the variable page spacing if necessary + if (mPageSpacing == AUTOMATIC_PAGE_SPACING) { + // The gap between pages in the PagedView should be equal to the gap from the page + // to the edge of the screen (so it is not visible in the current screen). To + // account for unequal padding on each side of the paged view, we take the maximum + // of the left/right gap and use that as the gap between each page. + int offset = getRelativeChildOffset(0); + int spacing = Math.max(offset, widthSize - offset - + getChildAt(0).getMeasuredWidth()); + setPageSpacing(spacing); + } + } + + updateScrollingIndicatorPosition(); + + if (childCount > 0) { + final int index = isLayoutRtl() ? 0 : childCount - 1; + mMaxScrollX = getChildOffset(index) - getRelativeChildOffset(index); + } else { + mMaxScrollX = 0; + } + } + + protected void scrollToNewPageWithoutMovingPages(int newCurrentPage) { + int newX = getChildOffset(newCurrentPage) - getRelativeChildOffset(newCurrentPage); + int delta = newX - getScrollX(); + + final int pageCount = getChildCount(); + for (int i = 0; i < pageCount; i++) { + View page = (View) getPageAt(i); + page.setX(page.getX() + delta); + } + setCurrentPage(newCurrentPage); + } + + // A layout scale of 1.0f assumes that the pages, in their unshrunken state, have a + // scale of 1.0f. A layout scale of 0.8f assumes the pages have a scale of 0.8f, and + // tightens the layout accordingly + public void setLayoutScale(float childrenScale) { + mLayoutScale = childrenScale; + invalidateCachedOffsets(); + + // Now we need to do a re-layout, but preserving absolute X and Y coordinates + int childCount = getChildCount(); + float childrenX[] = new float[childCount]; + float childrenY[] = new float[childCount]; + for (int i = 0; i < childCount; i++) { + final View child = getPageAt(i); + childrenX[i] = child.getX(); + childrenY[i] = child.getY(); + } + // Trigger a full re-layout (never just call onLayout directly!) + int widthSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth(), MeasureSpec.EXACTLY); + int heightSpec = MeasureSpec.makeMeasureSpec(getMeasuredHeight(), MeasureSpec.EXACTLY); + requestLayout(); + measure(widthSpec, heightSpec); + layout(getLeft(), getTop(), getRight(), getBottom()); + for (int i = 0; i < childCount; i++) { + final View child = getPageAt(i); + child.setX(childrenX[i]); + child.setY(childrenY[i]); + } + + // Also, the page offset has changed (since the pages are now smaller); + // update the page offset, but again preserving absolute X and Y coordinates + scrollToNewPageWithoutMovingPages(mCurrentPage); + } + + public void setPageSpacing(int pageSpacing) { + mPageSpacing = pageSpacing; + invalidateCachedOffsets(); + } + + @Override + protected void onLayout(boolean changed, int left, int top, int right, int bottom) { + if (!mIsDataReady) { + return; + } + + if (DEBUG) Log.d(TAG, "PagedView.onLayout()"); + final int verticalPadding = getPaddingTop() + getPaddingBottom(); + final int childCount = getChildCount(); + final boolean isRtl = isLayoutRtl(); + + final int startIndex = isRtl ? childCount - 1 : 0; + final int endIndex = isRtl ? -1 : childCount; + final int delta = isRtl ? -1 : 1; + int childLeft = getRelativeChildOffset(startIndex); + for (int i = startIndex; i != endIndex; i += delta) { + final View child = getPageAt(i); + if (child.getVisibility() != View.GONE) { + final int childWidth = getScaledMeasuredWidth(child); + final int childHeight = child.getMeasuredHeight(); + int childTop = getPaddingTop(); + if (mCenterPagesVertically) { + childTop += ((getMeasuredHeight() - verticalPadding) - childHeight) / 2; + } + + if (DEBUG) Log.d(TAG, "\tlayout-child" + i + ": " + childLeft + ", " + childTop); + child.layout(childLeft, childTop, + childLeft + child.getMeasuredWidth(), childTop + childHeight); + childLeft += childWidth + mPageSpacing; + } + } + + if (mFirstLayout && mCurrentPage >= 0 && mCurrentPage < getChildCount()) { + setHorizontalScrollBarEnabled(false); + updateCurrentPageScroll(); + setHorizontalScrollBarEnabled(true); + mFirstLayout = false; + } + } + + protected void screenScrolled(int screenCenter) { + if (isScrollingIndicatorEnabled()) { + updateScrollingIndicator(); + } + boolean isInOverscroll = mOverScrollX < 0 || mOverScrollX > mMaxScrollX; + + if (mFadeInAdjacentScreens && !isInOverscroll) { + for (int i = 0; i < getChildCount(); i++) { + View child = getChildAt(i); + if (child != null) { + float scrollProgress = getScrollProgress(screenCenter, child, i); + float alpha = 1 - Math.abs(scrollProgress); + child.setAlpha(alpha); + } + } + invalidate(); + } + } + + @Override + public void onChildViewAdded(View parent, View child) { + // This ensures that when children are added, they get the correct transforms / alphas + // in accordance with any scroll effects. + mForceScreenScrolled = true; + invalidate(); + invalidateCachedOffsets(); + } + + @Override + public void onChildViewRemoved(View parent, View child) { + } + + protected void invalidateCachedOffsets() { + int count = getChildCount(); + if (count == 0) { + mChildOffsets = null; + mChildRelativeOffsets = null; + mChildOffsetsWithLayoutScale = null; + return; + } + + mChildOffsets = new int[count]; + mChildRelativeOffsets = new int[count]; + mChildOffsetsWithLayoutScale = new int[count]; + for (int i = 0; i < count; i++) { + mChildOffsets[i] = -1; + mChildRelativeOffsets[i] = -1; + mChildOffsetsWithLayoutScale[i] = -1; + } + } + + protected int getChildOffset(int index) { + final boolean isRtl = isLayoutRtl(); + int[] childOffsets = Float.compare(mLayoutScale, 1f) == 0 ? + mChildOffsets : mChildOffsetsWithLayoutScale; + + if (childOffsets != null && childOffsets[index] != -1) { + return childOffsets[index]; + } else { + if (getChildCount() == 0) + return 0; + + final int startIndex = isRtl ? getChildCount() - 1 : 0; + final int endIndex = isRtl ? index : index; + final int delta = isRtl ? -1 : 1; + int offset = getRelativeChildOffset(startIndex); + for (int i = startIndex; i != endIndex; i += delta) { + offset += getScaledMeasuredWidth(getPageAt(i)) + mPageSpacing; + } + if (childOffsets != null) { + childOffsets[index] = offset; + } + return offset; + } + } + + protected int getRelativeChildOffset(int index) { + if (mChildRelativeOffsets != null && mChildRelativeOffsets[index] != -1) { + return mChildRelativeOffsets[index]; + } else { + final int padding = getPaddingLeft() + getPaddingRight(); + final int offset = getPaddingLeft() + + (getMeasuredWidth() - padding - getChildWidth(index)) / 2; + if (mChildRelativeOffsets != null) { + mChildRelativeOffsets[index] = offset; + } + return offset; + } + } + + protected int getScaledMeasuredWidth(View child) { + // This functions are called enough times that it actually makes a difference in the + // profiler -- so just inline the max() here + final int measuredWidth = child.getMeasuredWidth(); + final int minWidth = mMinimumWidth; + final int maxWidth = (minWidth > measuredWidth) ? minWidth : measuredWidth; + return (int) (maxWidth * mLayoutScale + 0.5f); + } + + protected void getVisiblePages(int[] range) { + final boolean isRtl = isLayoutRtl(); + final int pageCount = getChildCount(); + + if (pageCount > 0) { + final int screenWidth = getMeasuredWidth(); + int leftScreen = isRtl ? pageCount - 1 : 0; + int rightScreen = 0; + int endIndex = isRtl ? 0 : pageCount - 1; + int delta = isRtl ? -1 : 1; + View currPage = getPageAt(leftScreen); + while (leftScreen != endIndex && + currPage.getX() + currPage.getWidth() - + currPage.getPaddingRight() < getScrollX()) { + leftScreen += delta; + currPage = getPageAt(leftScreen); + } + rightScreen = leftScreen; + currPage = getPageAt(rightScreen + delta); + while (rightScreen != endIndex && + currPage.getX() - currPage.getPaddingLeft() < getScrollX() + screenWidth) { + rightScreen += delta; + currPage = getPageAt(rightScreen + delta); + } + range[0] = Math.min(leftScreen, rightScreen); + range[1] = Math.max(leftScreen, rightScreen); + } else { + range[0] = -1; + range[1] = -1; + } + } + + protected boolean shouldDrawChild(View child) { + return child.getAlpha() > 0; + } + + @Override + protected void dispatchDraw(Canvas canvas) { + int halfScreenSize = getMeasuredWidth() / 2; + // mOverScrollX is equal to getScrollX() when we're within the normal scroll range. + // Otherwise it is equal to the scaled overscroll position. + int screenCenter = mOverScrollX + halfScreenSize; + + if (screenCenter != mLastScreenCenter || mForceScreenScrolled) { + // set mForceScreenScrolled before calling screenScrolled so that screenScrolled can + // set it for the next frame + mForceScreenScrolled = false; + screenScrolled(screenCenter); + mLastScreenCenter = screenCenter; + } + + // Find out which screens are visible; as an optimization we only call draw on them + final int pageCount = getChildCount(); + if (pageCount > 0) { + getVisiblePages(mTempVisiblePagesRange); + final int leftScreen = mTempVisiblePagesRange[0]; + final int rightScreen = mTempVisiblePagesRange[1]; + if (leftScreen != -1 && rightScreen != -1) { + final long drawingTime = getDrawingTime(); + // Clip to the bounds + canvas.save(); + canvas.clipRect(getScrollX(), getScrollY(), getScrollX() + getRight() - getLeft(), + getScrollY() + getBottom() - getTop()); + + for (int i = getChildCount() - 1; i >= 0; i--) { + final View v = getPageAt(i); + if (mForceDrawAllChildrenNextFrame || + (leftScreen <= i && i <= rightScreen && shouldDrawChild(v))) { + drawChild(canvas, v, drawingTime); + } + } + mForceDrawAllChildrenNextFrame = false; + canvas.restore(); + } + } + } + + @Override + public boolean requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate) { + int page = indexToPage(indexOfChild(child)); + if (page != mCurrentPage || !mScroller.isFinished()) { + snapToPage(page); + return true; + } + return false; + } + + @Override + protected boolean onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect) { + int focusablePage; + if (mNextPage != INVALID_PAGE) { + focusablePage = mNextPage; + } else { + focusablePage = mCurrentPage; + } + View v = getPageAt(focusablePage); + if (v != null) { + return v.requestFocus(direction, previouslyFocusedRect); + } + return false; + } + + @Override + public boolean dispatchUnhandledMove(View focused, int direction) { + // XXX-RTL: This will be fixed in a future CL + if (direction == View.FOCUS_LEFT) { + if (getCurrentPage() > 0) { + snapToPage(getCurrentPage() - 1); + return true; + } + } else if (direction == View.FOCUS_RIGHT) { + if (getCurrentPage() < getPageCount() - 1) { + snapToPage(getCurrentPage() + 1); + return true; + } + } + return super.dispatchUnhandledMove(focused, direction); + } + + @Override + public void addFocusables(ArrayList<View> views, int direction, int focusableMode) { + // XXX-RTL: This will be fixed in a future CL + if (mCurrentPage >= 0 && mCurrentPage < getPageCount()) { + getPageAt(mCurrentPage).addFocusables(views, direction, focusableMode); + } + if (direction == View.FOCUS_LEFT) { + if (mCurrentPage > 0) { + getPageAt(mCurrentPage - 1).addFocusables(views, direction, focusableMode); + } + } else if (direction == View.FOCUS_RIGHT){ + if (mCurrentPage < getPageCount() - 1) { + getPageAt(mCurrentPage + 1).addFocusables(views, direction, focusableMode); + } + } + } + + /** + * If one of our descendant views decides that it could be focused now, only + * pass that along if it's on the current page. + * + * This happens when live folders requery, and if they're off page, they + * end up calling requestFocus, which pulls it on page. + */ + @Override + public void focusableViewAvailable(View focused) { + View current = getPageAt(mCurrentPage); + View v = focused; + while (true) { + if (v == current) { + super.focusableViewAvailable(focused); + return; + } + if (v == this) { + return; + } + ViewParent parent = v.getParent(); + if (parent instanceof View) { + v = (View)v.getParent(); + } else { + return; + } + } + } + + /** + * {@inheritDoc} + */ + @Override + public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) { + if (disallowIntercept) { + // We need to make sure to cancel our long press if + // a scrollable widget takes over touch events + final View currentPage = getPageAt(mCurrentPage); + currentPage.cancelLongPress(); + } + super.requestDisallowInterceptTouchEvent(disallowIntercept); + } + + /** + * Return true if a tap at (x, y) should trigger a flip to the previous page. + */ + protected boolean hitsPreviousPage(float x, float y) { + if (isLayoutRtl()) { + return (x > (getMeasuredWidth() - getRelativeChildOffset(mCurrentPage) + mPageSpacing)); + } else { + return (x < getRelativeChildOffset(mCurrentPage) - mPageSpacing); + } + } + + /** + * Return true if a tap at (x, y) should trigger a flip to the next page. + */ + protected boolean hitsNextPage(float x, float y) { + if (isLayoutRtl()) { + return (x < getRelativeChildOffset(mCurrentPage) - mPageSpacing); + } else { + return (x > (getMeasuredWidth() - getRelativeChildOffset(mCurrentPage) + mPageSpacing)); + } + + } + + @Override + public boolean onInterceptTouchEvent(MotionEvent ev) { + /* + * This method JUST determines whether we want to intercept the motion. + * If we return true, onTouchEvent will be called and we do the actual + * scrolling there. + */ + acquireVelocityTrackerAndAddMovement(ev); + + // Skip touch handling if there are no pages to swipe + if (getChildCount() <= 0) return super.onInterceptTouchEvent(ev); + + /* + * Shortcut the most recurring case: the user is in the dragging + * state and he is moving his finger. We want to intercept this + * motion. + */ + final int action = ev.getAction(); + if ((action == MotionEvent.ACTION_MOVE) && + (mTouchState == TOUCH_STATE_SCROLLING)) { + return true; + } + + switch (action & MotionEvent.ACTION_MASK) { + case MotionEvent.ACTION_MOVE: { + /* + * mIsBeingDragged == false, otherwise the shortcut would have caught it. Check + * whether the user has moved far enough from his original down touch. + */ + if (mActivePointerId != INVALID_POINTER) { + determineScrollingStart(ev); + break; + } + // if mActivePointerId is INVALID_POINTER, then we must have missed an ACTION_DOWN + // event. in that case, treat the first occurence of a move event as a ACTION_DOWN + // i.e. fall through to the next case (don't break) + // (We sometimes miss ACTION_DOWN events in Workspace because it ignores all events + // while it's small- this was causing a crash before we checked for INVALID_POINTER) + } + + case MotionEvent.ACTION_DOWN: { + final float x = ev.getX(); + final float y = ev.getY(); + // Remember location of down touch + mDownMotionX = x; + mLastMotionX = x; + mLastMotionY = y; + mLastMotionXRemainder = 0; + mTotalMotionX = 0; + mActivePointerId = ev.getPointerId(0); + mAllowLongPress = true; + + /* + * If being flinged and user touches the screen, initiate drag; + * otherwise don't. mScroller.isFinished should be false when + * being flinged. + */ + final int xDist = Math.abs(mScroller.getFinalX() - mScroller.getCurrX()); + final boolean finishedScrolling = (mScroller.isFinished() || xDist < mTouchSlop); + if (finishedScrolling) { + mTouchState = TOUCH_STATE_REST; + mScroller.abortAnimation(); + } else { + mTouchState = TOUCH_STATE_SCROLLING; + } + + // check if this can be the beginning of a tap on the side of the pages + // to scroll the current page + if (mTouchState != TOUCH_STATE_PREV_PAGE && mTouchState != TOUCH_STATE_NEXT_PAGE) { + if (getChildCount() > 0) { + if (hitsPreviousPage(x, y)) { + mTouchState = TOUCH_STATE_PREV_PAGE; + } else if (hitsNextPage(x, y)) { + mTouchState = TOUCH_STATE_NEXT_PAGE; + } + } + } + break; + } + + case MotionEvent.ACTION_UP: + case MotionEvent.ACTION_CANCEL: + mTouchState = TOUCH_STATE_REST; + mAllowLongPress = false; + mActivePointerId = INVALID_POINTER; + releaseVelocityTracker(); + break; + + case MotionEvent.ACTION_POINTER_UP: + onSecondaryPointerUp(ev); + releaseVelocityTracker(); + break; + } + + /* + * The only time we want to intercept motion events is if we are in the + * drag mode. + */ + return mTouchState != TOUCH_STATE_REST; + } + + protected void determineScrollingStart(MotionEvent ev) { + determineScrollingStart(ev, 1.0f); + } + + /* + * Determines if we should change the touch state to start scrolling after the + * user moves their touch point too far. + */ + protected void determineScrollingStart(MotionEvent ev, float touchSlopScale) { + /* + * Locally do absolute value. mLastMotionX is set to the y value + * of the down event. + */ + final int pointerIndex = ev.findPointerIndex(mActivePointerId); + if (pointerIndex == -1) { + return; + } + final float x = ev.getX(pointerIndex); + final float y = ev.getY(pointerIndex); + final int xDiff = (int) Math.abs(x - mLastMotionX); + final int yDiff = (int) Math.abs(y - mLastMotionY); + + final int touchSlop = Math.round(touchSlopScale * mTouchSlop); + boolean xPaged = xDiff > mPagingTouchSlop; + boolean xMoved = xDiff > touchSlop; + boolean yMoved = yDiff > touchSlop; + + if (xMoved || xPaged || yMoved) { + if (mUsePagingTouchSlop ? xPaged : xMoved) { + // Scroll if the user moved far enough along the X axis + mTouchState = TOUCH_STATE_SCROLLING; + mTotalMotionX += Math.abs(mLastMotionX - x); + mLastMotionX = x; + mLastMotionXRemainder = 0; + mTouchX = getScrollX(); + mSmoothingTime = System.nanoTime() / NANOTIME_DIV; + pageBeginMoving(); + } + // Either way, cancel any pending longpress + cancelCurrentPageLongPress(); + } + } + + protected void cancelCurrentPageLongPress() { + if (mAllowLongPress) { + mAllowLongPress = false; + // Try canceling the long press. It could also have been scheduled + // by a distant descendant, so use the mAllowLongPress flag to block + // everything + final View currentPage = getPageAt(mCurrentPage); + if (currentPage != null) { + currentPage.cancelLongPress(); + } + } + } + + protected float getScrollProgress(int screenCenter, View v, int page) { + final int halfScreenSize = getMeasuredWidth() / 2; + + int totalDistance = getScaledMeasuredWidth(v) + mPageSpacing; + int delta = screenCenter - (getChildOffset(page) - + getRelativeChildOffset(page) + halfScreenSize); + + float scrollProgress = delta / (totalDistance * 1.0f); + scrollProgress = Math.min(scrollProgress, 1.0f); + scrollProgress = Math.max(scrollProgress, -1.0f); + return scrollProgress; + } + + // This curve determines how the effect of scrolling over the limits of the page dimishes + // as the user pulls further and further from the bounds + private float overScrollInfluenceCurve(float f) { + f -= 1.0f; + return f * f * f + 1.0f; + } + + protected void acceleratedOverScroll(float amount) { + int screenSize = getMeasuredWidth(); + + // We want to reach the max over scroll effect when the user has + // over scrolled half the size of the screen + float f = OVERSCROLL_ACCELERATE_FACTOR * (amount / screenSize); + + if (f == 0) return; + + // Clamp this factor, f, to -1 < f < 1 + if (Math.abs(f) >= 1) { + f /= Math.abs(f); + } + + int overScrollAmount = (int) Math.round(f * screenSize); + if (amount < 0) { + mOverScrollX = overScrollAmount; + super.scrollTo(0, getScrollY()); + } else { + mOverScrollX = mMaxScrollX + overScrollAmount; + super.scrollTo(mMaxScrollX, getScrollY()); + } + invalidate(); + } + + protected void dampedOverScroll(float amount) { + int screenSize = getMeasuredWidth(); + + float f = (amount / screenSize); + + if (f == 0) return; + f = f / (Math.abs(f)) * (overScrollInfluenceCurve(Math.abs(f))); + + // Clamp this factor, f, to -1 < f < 1 + if (Math.abs(f) >= 1) { + f /= Math.abs(f); + } + + int overScrollAmount = (int) Math.round(OVERSCROLL_DAMP_FACTOR * f * screenSize); + if (amount < 0) { + mOverScrollX = overScrollAmount; + super.scrollTo(0, getScrollY()); + } else { + mOverScrollX = mMaxScrollX + overScrollAmount; + super.scrollTo(mMaxScrollX, getScrollY()); + } + invalidate(); + } + + protected void overScroll(float amount) { + dampedOverScroll(amount); + } + + protected float maxOverScroll() { + // Using the formula in overScroll, assuming that f = 1.0 (which it should generally not + // exceed). Used to find out how much extra wallpaper we need for the over scroll effect + float f = 1.0f; + f = f / (Math.abs(f)) * (overScrollInfluenceCurve(Math.abs(f))); + return OVERSCROLL_DAMP_FACTOR * f; + } + + @Override + public boolean onTouchEvent(MotionEvent ev) { + // Skip touch handling if there are no pages to swipe + if (getChildCount() <= 0) return super.onTouchEvent(ev); + + acquireVelocityTrackerAndAddMovement(ev); + + final int action = ev.getAction(); + + switch (action & MotionEvent.ACTION_MASK) { + case MotionEvent.ACTION_DOWN: + /* + * If being flinged and user touches, stop the fling. isFinished + * will be false if being flinged. + */ + if (!mScroller.isFinished()) { + mScroller.abortAnimation(); + } + + // Remember where the motion event started + mDownMotionX = mLastMotionX = ev.getX(); + mLastMotionXRemainder = 0; + mTotalMotionX = 0; + mActivePointerId = ev.getPointerId(0); + if (mTouchState == TOUCH_STATE_SCROLLING) { + pageBeginMoving(); + } + break; + + case MotionEvent.ACTION_MOVE: + if (mTouchState == TOUCH_STATE_SCROLLING) { + // Scroll to follow the motion event + final int pointerIndex = ev.findPointerIndex(mActivePointerId); + final float x = ev.getX(pointerIndex); + final float deltaX = mLastMotionX + mLastMotionXRemainder - x; + + mTotalMotionX += Math.abs(deltaX); + + // Only scroll and update mLastMotionX if we have moved some discrete amount. We + // keep the remainder because we are actually testing if we've moved from the last + // scrolled position (which is discrete). + if (Math.abs(deltaX) >= 1.0f) { + mTouchX += deltaX; + mSmoothingTime = System.nanoTime() / NANOTIME_DIV; + if (!mDeferScrollUpdate) { + scrollBy((int) deltaX, 0); + if (DEBUG) Log.d(TAG, "onTouchEvent().Scrolling: " + deltaX); + } else { + invalidate(); + } + mLastMotionX = x; + mLastMotionXRemainder = deltaX - (int) deltaX; + } else { + awakenScrollBars(); + } + } else { + determineScrollingStart(ev); + } + break; + + case MotionEvent.ACTION_UP: + if (mTouchState == TOUCH_STATE_SCROLLING) { + final int activePointerId = mActivePointerId; + final int pointerIndex = ev.findPointerIndex(activePointerId); + final float x = ev.getX(pointerIndex); + final VelocityTracker velocityTracker = mVelocityTracker; + velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); + int velocityX = (int) velocityTracker.getXVelocity(activePointerId); + final int deltaX = (int) (x - mDownMotionX); + final int pageWidth = getScaledMeasuredWidth(getPageAt(mCurrentPage)); + boolean isSignificantMove = Math.abs(deltaX) > pageWidth * + SIGNIFICANT_MOVE_THRESHOLD; + + mTotalMotionX += Math.abs(mLastMotionX + mLastMotionXRemainder - x); + + boolean isFling = mTotalMotionX > MIN_LENGTH_FOR_FLING && + Math.abs(velocityX) > mFlingThresholdVelocity; + + // In the case that the page is moved far to one direction and then is flung + // in the opposite direction, we use a threshold to determine whether we should + // just return to the starting page, or if we should skip one further. + boolean returnToOriginalPage = false; + if (Math.abs(deltaX) > pageWidth * RETURN_TO_ORIGINAL_PAGE_THRESHOLD && + Math.signum(velocityX) != Math.signum(deltaX) && isFling) { + returnToOriginalPage = true; + } + + int finalPage; + // We give flings precedence over large moves, which is why we short-circuit our + // test for a large move if a fling has been registered. That is, a large + // move to the left and fling to the right will register as a fling to the right. + final boolean isRtl = isLayoutRtl(); + boolean isDeltaXLeft = isRtl ? deltaX > 0 : deltaX < 0; + boolean isVelocityXLeft = isRtl ? velocityX > 0 : velocityX < 0; + if (((isSignificantMove && !isDeltaXLeft && !isFling) || + (isFling && !isVelocityXLeft)) && mCurrentPage > 0) { + finalPage = returnToOriginalPage ? mCurrentPage : mCurrentPage - 1; + snapToPageWithVelocity(finalPage, velocityX); + } else if (((isSignificantMove && isDeltaXLeft && !isFling) || + (isFling && isVelocityXLeft)) && + mCurrentPage < getChildCount() - 1) { + finalPage = returnToOriginalPage ? mCurrentPage : mCurrentPage + 1; + snapToPageWithVelocity(finalPage, velocityX); + } else { + snapToDestination(); + } + } else if (mTouchState == TOUCH_STATE_PREV_PAGE) { + // at this point we have not moved beyond the touch slop + // (otherwise mTouchState would be TOUCH_STATE_SCROLLING), so + // we can just page + int nextPage = Math.max(0, mCurrentPage - 1); + if (nextPage != mCurrentPage) { + snapToPage(nextPage); + } else { + snapToDestination(); + } + } else if (mTouchState == TOUCH_STATE_NEXT_PAGE) { + // at this point we have not moved beyond the touch slop + // (otherwise mTouchState would be TOUCH_STATE_SCROLLING), so + // we can just page + int nextPage = Math.min(getChildCount() - 1, mCurrentPage + 1); + if (nextPage != mCurrentPage) { + snapToPage(nextPage); + } else { + snapToDestination(); + } + } else { + onUnhandledTap(ev); + } + mTouchState = TOUCH_STATE_REST; + mActivePointerId = INVALID_POINTER; + releaseVelocityTracker(); + break; + + case MotionEvent.ACTION_CANCEL: + if (mTouchState == TOUCH_STATE_SCROLLING) { + snapToDestination(); + } + mTouchState = TOUCH_STATE_REST; + mActivePointerId = INVALID_POINTER; + releaseVelocityTracker(); + break; + + case MotionEvent.ACTION_POINTER_UP: + onSecondaryPointerUp(ev); + break; + } + + return true; + } + + @Override + public boolean onGenericMotionEvent(MotionEvent event) { + if ((event.getSource() & InputDevice.SOURCE_CLASS_POINTER) != 0) { + switch (event.getAction()) { + case MotionEvent.ACTION_SCROLL: { + // Handle mouse (or ext. device) by shifting the page depending on the scroll + final float vscroll; + final float hscroll; + if ((event.getMetaState() & KeyEvent.META_SHIFT_ON) != 0) { + vscroll = 0; + hscroll = event.getAxisValue(MotionEvent.AXIS_VSCROLL); + } else { + vscroll = -event.getAxisValue(MotionEvent.AXIS_VSCROLL); + hscroll = event.getAxisValue(MotionEvent.AXIS_HSCROLL); + } + if (hscroll != 0 || vscroll != 0) { + boolean isForwardScroll = isLayoutRtl() ? (hscroll < 0 || vscroll < 0) + : (hscroll > 0 || vscroll > 0); + if (isForwardScroll) { + scrollRight(); + } else { + scrollLeft(); + } + return true; + } + } + } + } + return super.onGenericMotionEvent(event); + } + + private void acquireVelocityTrackerAndAddMovement(MotionEvent ev) { + if (mVelocityTracker == null) { + mVelocityTracker = VelocityTracker.obtain(); + } + mVelocityTracker.addMovement(ev); + } + + private void releaseVelocityTracker() { + if (mVelocityTracker != null) { + mVelocityTracker.recycle(); + mVelocityTracker = null; + } + } + + private void onSecondaryPointerUp(MotionEvent ev) { + final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> + MotionEvent.ACTION_POINTER_INDEX_SHIFT; + final int pointerId = ev.getPointerId(pointerIndex); + if (pointerId == mActivePointerId) { + // This was our active pointer going up. Choose a new + // active pointer and adjust accordingly. + // TODO: Make this decision more intelligent. + final int newPointerIndex = pointerIndex == 0 ? 1 : 0; + mLastMotionX = mDownMotionX = ev.getX(newPointerIndex); + mLastMotionY = ev.getY(newPointerIndex); + mLastMotionXRemainder = 0; + mActivePointerId = ev.getPointerId(newPointerIndex); + if (mVelocityTracker != null) { + mVelocityTracker.clear(); + } + } + } + + protected void onUnhandledTap(MotionEvent ev) {} + + @Override + public void requestChildFocus(View child, View focused) { + super.requestChildFocus(child, focused); + int page = indexToPage(indexOfChild(child)); + if (page >= 0 && page != getCurrentPage() && !isInTouchMode()) { + snapToPage(page); + } + } + + protected int getChildIndexForRelativeOffset(int relativeOffset) { + final boolean isRtl = isLayoutRtl(); + final int childCount = getChildCount(); + int left; + int right; + final int startIndex = isRtl ? childCount - 1 : 0; + final int endIndex = isRtl ? -1 : childCount; + final int delta = isRtl ? -1 : 1; + for (int i = startIndex; i != endIndex; i += delta) { + left = getRelativeChildOffset(i); + right = (left + getScaledMeasuredWidth(getPageAt(i))); + if (left <= relativeOffset && relativeOffset <= right) { + return i; + } + } + return -1; + } + + protected int getChildWidth(int index) { + // This functions are called enough times that it actually makes a difference in the + // profiler -- so just inline the max() here + final int measuredWidth = getPageAt(index).getMeasuredWidth(); + final int minWidth = mMinimumWidth; + return (minWidth > measuredWidth) ? minWidth : measuredWidth; + } + + int getPageNearestToCenterOfScreen() { + int minDistanceFromScreenCenter = Integer.MAX_VALUE; + int minDistanceFromScreenCenterIndex = -1; + int screenCenter = getScrollX() + (getMeasuredWidth() / 2); + final int childCount = getChildCount(); + for (int i = 0; i < childCount; ++i) { + View layout = (View) getPageAt(i); + int childWidth = getScaledMeasuredWidth(layout); + int halfChildWidth = (childWidth / 2); + int childCenter = getChildOffset(i) + halfChildWidth; + int distanceFromScreenCenter = Math.abs(childCenter - screenCenter); + if (distanceFromScreenCenter < minDistanceFromScreenCenter) { + minDistanceFromScreenCenter = distanceFromScreenCenter; + minDistanceFromScreenCenterIndex = i; + } + } + return minDistanceFromScreenCenterIndex; + } + + protected void snapToDestination() { + snapToPage(getPageNearestToCenterOfScreen(), PAGE_SNAP_ANIMATION_DURATION); + } + + private static class ScrollInterpolator implements Interpolator { + public ScrollInterpolator() { + } + + public float getInterpolation(float t) { + t -= 1.0f; + return t*t*t*t*t + 1; + } + } + + // We want the duration of the page snap animation to be influenced by the distance that + // the screen has to travel, however, we don't want this duration to be effected in a + // purely linear fashion. Instead, we use this method to moderate the effect that the distance + // of travel has on the overall snap duration. + float distanceInfluenceForSnapDuration(float f) { + f -= 0.5f; // center the values about 0. + f *= 0.3f * Math.PI / 2.0f; + return (float) Math.sin(f); + } + + protected void snapToPageWithVelocity(int whichPage, int velocity) { + whichPage = Math.max(0, Math.min(whichPage, getChildCount() - 1)); + int halfScreenSize = getMeasuredWidth() / 2; + + if (DEBUG) Log.d(TAG, "snapToPage.getChildOffset(): " + getChildOffset(whichPage)); + if (DEBUG) Log.d(TAG, "snapToPageWithVelocity.getRelativeChildOffset(): " + + getMeasuredWidth() + ", " + getChildWidth(whichPage)); + final int newX = getChildOffset(whichPage) - getRelativeChildOffset(whichPage); + int delta = newX - mUnboundedScrollX; + int duration = 0; + + if (Math.abs(velocity) < mMinFlingVelocity) { + // If the velocity is low enough, then treat this more as an automatic page advance + // as opposed to an apparent physical response to flinging + snapToPage(whichPage, PAGE_SNAP_ANIMATION_DURATION); + return; + } + + // Here we compute a "distance" that will be used in the computation of the overall + // snap duration. This is a function of the actual distance that needs to be traveled; + // we keep this value close to half screen size in order to reduce the variance in snap + // duration as a function of the distance the page needs to travel. + float distanceRatio = Math.min(1f, 1.0f * Math.abs(delta) / (2 * halfScreenSize)); + float distance = halfScreenSize + halfScreenSize * + distanceInfluenceForSnapDuration(distanceRatio); + + velocity = Math.abs(velocity); + velocity = Math.max(mMinSnapVelocity, velocity); + + // we want the page's snap velocity to approximately match the velocity at which the + // user flings, so we scale the duration by a value near to the derivative of the scroll + // interpolator at zero, ie. 5. We use 4 to make it a little slower. + duration = 4 * Math.round(1000 * Math.abs(distance / velocity)); + duration = Math.min(duration, MAX_PAGE_SNAP_DURATION); + + snapToPage(whichPage, delta, duration); + } + + protected void snapToPage(int whichPage) { + snapToPage(whichPage, PAGE_SNAP_ANIMATION_DURATION); + } + + protected void snapToPage(int whichPage, int duration) { + whichPage = Math.max(0, Math.min(whichPage, getPageCount() - 1)); + + if (DEBUG) Log.d(TAG, "snapToPage.getChildOffset(): " + getChildOffset(whichPage)); + if (DEBUG) Log.d(TAG, "snapToPage.getRelativeChildOffset(): " + getMeasuredWidth() + ", " + + getChildWidth(whichPage)); + int newX = getChildOffset(whichPage) - getRelativeChildOffset(whichPage); + final int sX = mUnboundedScrollX; + final int delta = newX - sX; + snapToPage(whichPage, delta, duration); + } + + protected void snapToPage(int whichPage, int delta, int duration) { + mNextPage = whichPage; + + View focusedChild = getFocusedChild(); + if (focusedChild != null && whichPage != mCurrentPage && + focusedChild == getPageAt(mCurrentPage)) { + focusedChild.clearFocus(); + } + + pageBeginMoving(); + awakenScrollBars(duration); + if (duration == 0) { + duration = Math.abs(delta); + } + + if (!mScroller.isFinished()) mScroller.abortAnimation(); + mScroller.startScroll(mUnboundedScrollX, 0, delta, 0, duration); + + // Load associated pages immediately if someone else is handling the scroll, otherwise defer + // loading associated pages until the scroll settles + if (mDeferScrollUpdate) { + loadAssociatedPages(mNextPage); + } else { + mDeferLoadAssociatedPagesUntilScrollCompletes = true; + } + notifyPageSwitchListener(); + invalidate(); + } + + public void scrollLeft() { + if (mScroller.isFinished()) { + if (mCurrentPage > 0) snapToPage(mCurrentPage - 1); + } else { + if (mNextPage > 0) snapToPage(mNextPage - 1); + } + } + + public void scrollRight() { + if (mScroller.isFinished()) { + if (mCurrentPage < getChildCount() -1) snapToPage(mCurrentPage + 1); + } else { + if (mNextPage < getChildCount() -1) snapToPage(mNextPage + 1); + } + } + + public int getPageForView(View v) { + int result = -1; + if (v != null) { + ViewParent vp = v.getParent(); + int count = getChildCount(); + for (int i = 0; i < count; i++) { + if (vp == getPageAt(i)) { + return i; + } + } + } + return result; + } + + /** + * @return True is long presses are still allowed for the current touch + */ + public boolean allowLongPress() { + return mAllowLongPress; + } + + /** + * Set true to allow long-press events to be triggered, usually checked by + * {@link Launcher} to accept or block dpad-initiated long-presses. + */ + public void setAllowLongPress(boolean allowLongPress) { + mAllowLongPress = allowLongPress; + } + + public static class SavedState extends BaseSavedState { + int currentPage = -1; + + SavedState(Parcelable superState) { + super(superState); + } + + private SavedState(Parcel in) { + super(in); + currentPage = in.readInt(); + } + + @Override + public void writeToParcel(Parcel out, int flags) { + super.writeToParcel(out, flags); + out.writeInt(currentPage); + } + + public static final Parcelable.Creator<SavedState> CREATOR = + new Parcelable.Creator<SavedState>() { + public SavedState createFromParcel(Parcel in) { + return new SavedState(in); + } + + public SavedState[] newArray(int size) { + return new SavedState[size]; + } + }; + } + + protected void loadAssociatedPages(int page) { + loadAssociatedPages(page, false); + } + protected void loadAssociatedPages(int page, boolean immediateAndOnly) { + if (mContentIsRefreshable) { + final int count = getChildCount(); + if (page < count) { + int lowerPageBound = getAssociatedLowerPageBound(page); + int upperPageBound = getAssociatedUpperPageBound(page); + if (DEBUG) Log.d(TAG, "loadAssociatedPages: " + lowerPageBound + "/" + + upperPageBound); + // First, clear any pages that should no longer be loaded + for (int i = 0; i < count; ++i) { + Page layout = (Page) getPageAt(i); + if ((i < lowerPageBound) || (i > upperPageBound)) { + if (layout.getPageChildCount() > 0) { + layout.removeAllViewsOnPage(); + } + mDirtyPageContent.set(i, true); + } + } + // Next, load any new pages + for (int i = 0; i < count; ++i) { + if ((i != page) && immediateAndOnly) { + continue; + } + if (lowerPageBound <= i && i <= upperPageBound) { + if (mDirtyPageContent.get(i)) { + syncPageItems(i, (i == page) && immediateAndOnly); + mDirtyPageContent.set(i, false); + } + } + } + } + } + } + + protected int getAssociatedLowerPageBound(int page) { + return Math.max(0, page - 1); + } + protected int getAssociatedUpperPageBound(int page) { + final int count = getChildCount(); + return Math.min(page + 1, count - 1); + } + + /** + * This method is called ONLY to synchronize the number of pages that the paged view has. + * To actually fill the pages with information, implement syncPageItems() below. It is + * guaranteed that syncPageItems() will be called for a particular page before it is shown, + * and therefore, individual page items do not need to be updated in this method. + */ + public abstract void syncPages(); + + /** + * This method is called to synchronize the items that are on a particular page. If views on + * the page can be reused, then they should be updated within this method. + */ + public abstract void syncPageItems(int page, boolean immediate); + + protected void invalidatePageData() { + invalidatePageData(-1, false); + } + protected void invalidatePageData(int currentPage) { + invalidatePageData(currentPage, false); + } + protected void invalidatePageData(int currentPage, boolean immediateAndOnly) { + if (!mIsDataReady) { + return; + } + + if (mContentIsRefreshable) { + // Force all scrolling-related behavior to end + mScroller.forceFinished(true); + mNextPage = INVALID_PAGE; + + // Update all the pages + syncPages(); + + // We must force a measure after we've loaded the pages to update the content width and + // to determine the full scroll width + measure(MeasureSpec.makeMeasureSpec(getMeasuredWidth(), MeasureSpec.EXACTLY), + MeasureSpec.makeMeasureSpec(getMeasuredHeight(), MeasureSpec.EXACTLY)); + + // Set a new page as the current page if necessary + if (currentPage > -1) { + setCurrentPage(Math.min(getPageCount() - 1, currentPage)); + } + + // Mark each of the pages as dirty + final int count = getChildCount(); + mDirtyPageContent.clear(); + for (int i = 0; i < count; ++i) { + mDirtyPageContent.add(true); + } + + // Load any pages that are necessary for the current window of views + loadAssociatedPages(mCurrentPage, immediateAndOnly); + requestLayout(); + } + } + + protected View getScrollingIndicator() { + // We use mHasScrollIndicator to prevent future lookups if there is no sibling indicator + // found + if (mHasScrollIndicator && mScrollIndicator == null) { + ViewGroup parent = (ViewGroup) getParent(); + if (parent != null) { + mScrollIndicator = (View) (parent.findViewById(R.id.paged_view_indicator)); + mHasScrollIndicator = mScrollIndicator != null; + if (mHasScrollIndicator) { + mScrollIndicator.setVisibility(View.VISIBLE); + } + } + } + return mScrollIndicator; + } + + protected boolean isScrollingIndicatorEnabled() { + return true; + } + + Runnable hideScrollingIndicatorRunnable = new Runnable() { + @Override + public void run() { + hideScrollingIndicator(false); + } + }; + protected void flashScrollingIndicator(boolean animated) { + removeCallbacks(hideScrollingIndicatorRunnable); + showScrollingIndicator(!animated); + postDelayed(hideScrollingIndicatorRunnable, sScrollIndicatorFlashDuration); + } + + protected void showScrollingIndicator(boolean immediately) { + mShouldShowScrollIndicator = true; + mShouldShowScrollIndicatorImmediately = true; + if (getChildCount() <= 1) return; + if (!isScrollingIndicatorEnabled()) return; + + mShouldShowScrollIndicator = false; + getScrollingIndicator(); + if (mScrollIndicator != null) { + // Fade the indicator in + updateScrollingIndicatorPosition(); + mScrollIndicator.setVisibility(View.VISIBLE); + cancelScrollingIndicatorAnimations(); + if (immediately || mScrollingPaused) { + mScrollIndicator.setAlpha(1f); + } else { + mScrollIndicatorAnimator = LauncherAnimUtils.ofFloat(mScrollIndicator, "alpha", 1f); + mScrollIndicatorAnimator.setDuration(sScrollIndicatorFadeInDuration); + mScrollIndicatorAnimator.start(); + } + } + } + + protected void cancelScrollingIndicatorAnimations() { + if (mScrollIndicatorAnimator != null) { + mScrollIndicatorAnimator.cancel(); + } + } + + protected void hideScrollingIndicator(boolean immediately) { + if (getChildCount() <= 1) return; + if (!isScrollingIndicatorEnabled()) return; + + getScrollingIndicator(); + if (mScrollIndicator != null) { + // Fade the indicator out + updateScrollingIndicatorPosition(); + cancelScrollingIndicatorAnimations(); + if (immediately || mScrollingPaused) { + mScrollIndicator.setVisibility(View.INVISIBLE); + mScrollIndicator.setAlpha(0f); + } else { + mScrollIndicatorAnimator = LauncherAnimUtils.ofFloat(mScrollIndicator, "alpha", 0f); + mScrollIndicatorAnimator.setDuration(sScrollIndicatorFadeOutDuration); + mScrollIndicatorAnimator.addListener(new AnimatorListenerAdapter() { + private boolean cancelled = false; + @Override + public void onAnimationCancel(android.animation.Animator animation) { + cancelled = true; + } + @Override + public void onAnimationEnd(Animator animation) { + if (!cancelled) { + mScrollIndicator.setVisibility(View.INVISIBLE); + } + } + }); + mScrollIndicatorAnimator.start(); + } + } + } + + /** + * To be overridden by subclasses to determine whether the scroll indicator should stretch to + * fill its space on the track or not. + */ + protected boolean hasElasticScrollIndicator() { + return true; + } + + private void updateScrollingIndicator() { + if (getChildCount() <= 1) return; + if (!isScrollingIndicatorEnabled()) return; + + getScrollingIndicator(); + if (mScrollIndicator != null) { + updateScrollingIndicatorPosition(); + } + if (mShouldShowScrollIndicator) { + showScrollingIndicator(mShouldShowScrollIndicatorImmediately); + } + } + + private void updateScrollingIndicatorPosition() { + final boolean isRtl = isLayoutRtl(); + if (!isScrollingIndicatorEnabled()) return; + if (mScrollIndicator == null) return; + int numPages = getChildCount(); + int pageWidth = getMeasuredWidth(); + int trackWidth = pageWidth - mScrollIndicatorPaddingLeft - mScrollIndicatorPaddingRight; + int indicatorWidth = mScrollIndicator.getMeasuredWidth() - + mScrollIndicator.getPaddingLeft() - mScrollIndicator.getPaddingRight(); + + float scrollPos = isRtl ? mMaxScrollX - getScrollX() : getScrollX(); + float offset = Math.max(0f, Math.min(1f, (float) scrollPos / mMaxScrollX)); + if (isRtl) { + offset = 1f - offset; + } + int indicatorSpace = trackWidth / numPages; + int indicatorPos = (int) (offset * (trackWidth - indicatorSpace)) + mScrollIndicatorPaddingLeft; + if (hasElasticScrollIndicator()) { + if (mScrollIndicator.getMeasuredWidth() != indicatorSpace) { + mScrollIndicator.getLayoutParams().width = indicatorSpace; + mScrollIndicator.requestLayout(); + } + } else { + int indicatorCenterOffset = indicatorSpace / 2 - indicatorWidth / 2; + indicatorPos += indicatorCenterOffset; + } + mScrollIndicator.setTranslationX(indicatorPos); + } + + public void showScrollIndicatorTrack() { + } + + public void hideScrollIndicatorTrack() { + } + + /* Accessibility */ + @Override + public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) { + super.onInitializeAccessibilityNodeInfo(info); + info.setScrollable(getPageCount() > 1); + if (getCurrentPage() < getPageCount() - 1) { + info.addAction(AccessibilityNodeInfo.ACTION_SCROLL_FORWARD); + } + if (getCurrentPage() > 0) { + info.addAction(AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD); + } + } + + @Override + public void onInitializeAccessibilityEvent(AccessibilityEvent event) { + super.onInitializeAccessibilityEvent(event); + event.setScrollable(true); + if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_SCROLLED) { + event.setFromIndex(mCurrentPage); + event.setToIndex(mCurrentPage); + event.setItemCount(getChildCount()); + } + } + + @Override + public boolean performAccessibilityAction(int action, Bundle arguments) { + if (super.performAccessibilityAction(action, arguments)) { + return true; + } + switch (action) { + case AccessibilityNodeInfo.ACTION_SCROLL_FORWARD: { + if (getCurrentPage() < getPageCount() - 1) { + scrollRight(); + return true; + } + } break; + case AccessibilityNodeInfo.ACTION_SCROLL_BACKWARD: { + if (getCurrentPage() > 0) { + scrollLeft(); + return true; + } + } break; + } + return false; + } + + protected String getCurrentPageDescription() { + return String.format(getContext().getString(R.string.default_scroll_format), + getNextPage() + 1, getChildCount()); + } + + @Override + public boolean onHoverEvent(android.view.MotionEvent event) { + return true; + } +} |