diff options
Diffstat (limited to 'src/com/android/launcher3/list/PinnedHeaderListView.java')
| -rw-r--r-- | src/com/android/launcher3/list/PinnedHeaderListView.java | 565 |
1 files changed, 565 insertions, 0 deletions
diff --git a/src/com/android/launcher3/list/PinnedHeaderListView.java b/src/com/android/launcher3/list/PinnedHeaderListView.java new file mode 100644 index 000000000..30688fea3 --- /dev/null +++ b/src/com/android/launcher3/list/PinnedHeaderListView.java @@ -0,0 +1,565 @@ +/* + * 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.list; + +import android.content.Context; +import android.graphics.Canvas; +import android.graphics.Rect; +import android.graphics.RectF; +import android.util.AttributeSet; +import android.util.Log; +import android.view.MotionEvent; +import android.view.View; +import android.view.ViewGroup; +import android.widget.AbsListView; +import android.widget.AbsListView.OnScrollListener; +import android.widget.AdapterView; +import android.widget.AdapterView.OnItemSelectedListener; +import android.widget.ListAdapter; + +/** + * A ListView that maintains a header pinned at the top of the list. The + * pinned header can be pushed up and dissolved as needed. + */ +public class PinnedHeaderListView extends AutoScrollListView + implements OnScrollListener, OnItemSelectedListener { + + /** + * Adapter interface. The list adapter must implement this interface. + */ + public interface PinnedHeaderAdapter { + + /** + * Returns the overall number of pinned headers, visible or not. + */ + int getPinnedHeaderCount(); + + /** + * Creates or updates the pinned header view. + */ + View getPinnedHeaderView(int viewIndex, View convertView, ViewGroup parent); + + /** + * Configures the pinned headers to match the visible list items. The + * adapter should call {@link PinnedHeaderListView#setHeaderPinnedAtTop}, + * {@link PinnedHeaderListView#setHeaderPinnedAtBottom}, + * {@link PinnedHeaderListView#setFadingHeader} or + * {@link PinnedHeaderListView#setHeaderInvisible}, for each header that + * needs to change its position or visibility. + */ + void configurePinnedHeaders(PinnedHeaderListView listView); + + /** + * Returns the list position to scroll to if the pinned header is touched. + * Return -1 if the list does not need to be scrolled. + */ + int getScrollPositionForHeader(int viewIndex); + } + + private static final int MAX_ALPHA = 255; + private static final int TOP = 0; + private static final int BOTTOM = 1; + private static final int FADING = 2; + + private static final int DEFAULT_ANIMATION_DURATION = 20; + + private static final int DEFAULT_SMOOTH_SCROLL_DURATION = 100; + + private static final class PinnedHeader { + View view; + boolean visible; + int y; + int height; + int alpha; + int state; + + boolean animating; + boolean targetVisible; + int sourceY; + int targetY; + long targetTime; + } + + private PinnedHeaderAdapter mAdapter; + private int mSize; + private PinnedHeader[] mHeaders; + private RectF mBounds = new RectF(); + private Rect mClipRect = new Rect(); + private OnScrollListener mOnScrollListener; + private OnItemSelectedListener mOnItemSelectedListener; + private int mScrollState; + + private boolean mScrollToSectionOnHeaderTouch = false; + private boolean mHeaderTouched = false; + + private int mAnimationDuration = DEFAULT_ANIMATION_DURATION; + private boolean mAnimating; + private long mAnimationTargetTime; + private int mHeaderPaddingStart; + private int mHeaderWidth; + + public PinnedHeaderListView(Context context) { + this(context, null, android.R.attr.listViewStyle); + } + + public PinnedHeaderListView(Context context, AttributeSet attrs) { + this(context, attrs, android.R.attr.listViewStyle); + } + + public PinnedHeaderListView(Context context, AttributeSet attrs, int defStyle) { + super(context, attrs, defStyle); + super.setOnScrollListener(this); + super.setOnItemSelectedListener(this); + } + + @Override + protected void onLayout(boolean changed, int l, int t, int r, int b) { + super.onLayout(changed, l, t, r, b); + mHeaderPaddingStart = getPaddingStart(); + mHeaderWidth = r - l - mHeaderPaddingStart - getPaddingEnd(); + } + + public void setPinnedHeaderAnimationDuration(int duration) { + mAnimationDuration = duration; + } + + @Override + public void setAdapter(ListAdapter adapter) { + mAdapter = (PinnedHeaderAdapter)adapter; + super.setAdapter(adapter); + } + + @Override + public void setOnScrollListener(OnScrollListener onScrollListener) { + mOnScrollListener = onScrollListener; + super.setOnScrollListener(this); + } + + @Override + public void setOnItemSelectedListener(OnItemSelectedListener listener) { + mOnItemSelectedListener = listener; + super.setOnItemSelectedListener(this); + } + + public void setScrollToSectionOnHeaderTouch(boolean value) { + mScrollToSectionOnHeaderTouch = value; + } + + @Override + public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, + int totalItemCount) { + if (mAdapter != null) { + int count = mAdapter.getPinnedHeaderCount(); + if (count != mSize) { + mSize = count; + if (mHeaders == null) { + mHeaders = new PinnedHeader[mSize]; + } else if (mHeaders.length < mSize) { + PinnedHeader[] headers = mHeaders; + mHeaders = new PinnedHeader[mSize]; + System.arraycopy(headers, 0, mHeaders, 0, headers.length); + } + } + + for (int i = 0; i < mSize; i++) { + if (mHeaders[i] == null) { + mHeaders[i] = new PinnedHeader(); + } + mHeaders[i].view = mAdapter.getPinnedHeaderView(i, mHeaders[i].view, this); + } + + mAnimationTargetTime = System.currentTimeMillis() + mAnimationDuration; + mAdapter.configurePinnedHeaders(this); + invalidateIfAnimating(); + + } + if (mOnScrollListener != null) { + mOnScrollListener.onScroll(this, firstVisibleItem, visibleItemCount, totalItemCount); + } + } + + @Override + protected float getTopFadingEdgeStrength() { + // Disable vertical fading at the top when the pinned header is present + return mSize > 0 ? 0 : super.getTopFadingEdgeStrength(); + } + + @Override + public void onScrollStateChanged(AbsListView view, int scrollState) { + mScrollState = scrollState; + if (mOnScrollListener != null) { + mOnScrollListener.onScrollStateChanged(this, scrollState); + } + } + + /** + * Ensures that the selected item is positioned below the top-pinned headers + * and above the bottom-pinned ones. + */ + @Override + public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { + int height = getHeight(); + + int windowTop = 0; + int windowBottom = height; + + for (int i = 0; i < mSize; i++) { + PinnedHeader header = mHeaders[i]; + if (header.visible) { + if (header.state == TOP) { + windowTop = header.y + header.height; + } else if (header.state == BOTTOM) { + windowBottom = header.y; + break; + } + } + } + + View selectedView = getSelectedView(); + if (selectedView != null) { + if (selectedView.getTop() < windowTop) { + setSelectionFromTop(position, windowTop); + } else if (selectedView.getBottom() > windowBottom) { + setSelectionFromTop(position, windowBottom - selectedView.getHeight()); + } + } + + if (mOnItemSelectedListener != null) { + mOnItemSelectedListener.onItemSelected(parent, view, position, id); + } + } + + @Override + public void onNothingSelected(AdapterView<?> parent) { + if (mOnItemSelectedListener != null) { + mOnItemSelectedListener.onNothingSelected(parent); + } + } + + public int getPinnedHeaderHeight(int viewIndex) { + ensurePinnedHeaderLayout(viewIndex); + return mHeaders[viewIndex].view.getHeight(); + } + + /** + * Set header to be pinned at the top. + * + * @param viewIndex index of the header view + * @param y is position of the header in pixels. + * @param animate true if the transition to the new coordinate should be animated + */ + public void setHeaderPinnedAtTop(int viewIndex, int y, boolean animate) { + ensurePinnedHeaderLayout(viewIndex); + PinnedHeader header = mHeaders[viewIndex]; + header.visible = true; + header.y = y; + header.state = TOP; + + // TODO perhaps we should animate at the top as well + header.animating = false; + } + + /** + * Set header to be pinned at the bottom. + * + * @param viewIndex index of the header view + * @param y is position of the header in pixels. + * @param animate true if the transition to the new coordinate should be animated + */ + public void setHeaderPinnedAtBottom(int viewIndex, int y, boolean animate) { + ensurePinnedHeaderLayout(viewIndex); + PinnedHeader header = mHeaders[viewIndex]; + header.state = BOTTOM; + if (header.animating) { + header.targetTime = mAnimationTargetTime; + header.sourceY = header.y; + header.targetY = y; + } else if (animate && (header.y != y || !header.visible)) { + if (header.visible) { + header.sourceY = header.y; + } else { + header.visible = true; + header.sourceY = y + header.height; + } + header.animating = true; + header.targetVisible = true; + header.targetTime = mAnimationTargetTime; + header.targetY = y; + } else { + header.visible = true; + header.y = y; + } + } + + /** + * Set header to be pinned at the top of the first visible item. + * + * @param viewIndex index of the header view + * @param position is position of the header in pixels. + */ + public void setFadingHeader(int viewIndex, int position, boolean fade) { + ensurePinnedHeaderLayout(viewIndex); + + View child = getChildAt(position - getFirstVisiblePosition()); + if (child == null) return; + + PinnedHeader header = mHeaders[viewIndex]; + header.visible = true; + header.state = FADING; + header.alpha = MAX_ALPHA; + header.animating = false; + + int top = getTotalTopPinnedHeaderHeight(); + header.y = top; + if (fade) { + int bottom = child.getBottom() - top; + int headerHeight = header.height; + if (bottom < headerHeight) { + int portion = bottom - headerHeight; + header.alpha = MAX_ALPHA * (headerHeight + portion) / headerHeight; + header.y = top + portion; + } + } + } + + /** + * Makes header invisible. + * + * @param viewIndex index of the header view + * @param animate true if the transition to the new coordinate should be animated + */ + public void setHeaderInvisible(int viewIndex, boolean animate) { + PinnedHeader header = mHeaders[viewIndex]; + if (header.visible && (animate || header.animating) && header.state == BOTTOM) { + header.sourceY = header.y; + if (!header.animating) { + header.visible = true; + header.targetY = getBottom() + header.height; + } + header.animating = true; + header.targetTime = mAnimationTargetTime; + header.targetVisible = false; + } else { + header.visible = false; + } + } + + private void ensurePinnedHeaderLayout(int viewIndex) { + View view = mHeaders[viewIndex].view; + if (view.isLayoutRequested()) { + int widthSpec = View.MeasureSpec.makeMeasureSpec(mHeaderWidth, View.MeasureSpec.EXACTLY); + int heightSpec; + ViewGroup.LayoutParams layoutParams = view.getLayoutParams(); + if (layoutParams != null && layoutParams.height > 0) { + heightSpec = View.MeasureSpec + .makeMeasureSpec(layoutParams.height, View.MeasureSpec.EXACTLY); + } else { + heightSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED); + } + view.measure(widthSpec, heightSpec); + int height = view.getMeasuredHeight(); + mHeaders[viewIndex].height = height; + view.layout(0, 0, mHeaderWidth, height); + } + } + + /** + * Returns the sum of heights of headers pinned to the top. + */ + public int getTotalTopPinnedHeaderHeight() { + for (int i = mSize; --i >= 0;) { + PinnedHeader header = mHeaders[i]; + if (header.visible && header.state == TOP) { + return header.y + header.height; + } + } + return 0; + } + + /** + * Returns the list item position at the specified y coordinate. + */ + public int getPositionAt(int y) { + do { + int position = pointToPosition(getPaddingLeft() + 1, y); + if (position != -1) { + return position; + } + // If position == -1, we must have hit a separator. Let's examine + // a nearby pixel + y--; + } while (y > 0); + return 0; + } + + @Override + public boolean onInterceptTouchEvent(MotionEvent ev) { + mHeaderTouched = false; + if (super.onInterceptTouchEvent(ev)) { + return true; + } + + if (mScrollState == SCROLL_STATE_IDLE) { + final int y = (int)ev.getY(); + final int x = (int)ev.getX(); + for (int i = mSize; --i >= 0;) { + PinnedHeader header = mHeaders[i]; + // For RTL layouts, this also takes into account that the scrollbar is on the left + // side. + final int padding = getPaddingLeft(); + if (header.visible && header.y <= y && header.y + header.height > y && + x >= padding && padding + mHeaderWidth >= x) { + mHeaderTouched = true; + if (mScrollToSectionOnHeaderTouch && + ev.getAction() == MotionEvent.ACTION_DOWN) { + return smoothScrollToPartition(i); + } else { + return true; + } + } + } + } + + return false; + } + + @Override + public boolean onTouchEvent(MotionEvent ev) { + if (mHeaderTouched) { + if (ev.getAction() == MotionEvent.ACTION_UP) { + mHeaderTouched = false; + } + return true; + } + return super.onTouchEvent(ev); + }; + + private boolean smoothScrollToPartition(int partition) { + final int position = mAdapter.getScrollPositionForHeader(partition); + if (position == -1) { + return false; + } + + int offset = 0; + for (int i = 0; i < partition; i++) { + PinnedHeader header = mHeaders[i]; + if (header.visible) { + offset += header.height; + } + } + smoothScrollToPositionFromTop(position + getHeaderViewsCount(), offset, + DEFAULT_SMOOTH_SCROLL_DURATION); + return true; + } + + private void invalidateIfAnimating() { + mAnimating = false; + for (int i = 0; i < mSize; i++) { + if (mHeaders[i].animating) { + mAnimating = true; + invalidate(); + return; + } + } + } + + @Override + protected void dispatchDraw(Canvas canvas) { + long currentTime = mAnimating ? System.currentTimeMillis() : 0; + + int top = 0; + int bottom = getBottom(); + boolean hasVisibleHeaders = false; + for (int i = 0; i < mSize; i++) { + PinnedHeader header = mHeaders[i]; + if (header.visible) { + hasVisibleHeaders = true; + if (header.state == BOTTOM && header.y < bottom) { + bottom = header.y; + } else if (header.state == TOP || header.state == FADING) { + int newTop = header.y + header.height; + if (newTop > top) { + top = newTop; + } + } + } + } + + if (hasVisibleHeaders) { + canvas.save(); + mClipRect.set(0, top, getWidth(), bottom); + canvas.clipRect(mClipRect); + } + + super.dispatchDraw(canvas); + + if (hasVisibleHeaders) { + canvas.restore(); + + // First draw top headers, then the bottom ones to handle the Z axis correctly + for (int i = mSize; --i >= 0;) { + PinnedHeader header = mHeaders[i]; + if (header.visible && (header.state == TOP || header.state == FADING)) { + drawHeader(canvas, header, currentTime); + } + } + + for (int i = 0; i < mSize; i++) { + PinnedHeader header = mHeaders[i]; + if (header.visible && header.state == BOTTOM) { + drawHeader(canvas, header, currentTime); + } + } + } + + invalidateIfAnimating(); + } + + private void drawHeader(Canvas canvas, PinnedHeader header, long currentTime) { + if (header.animating) { + int timeLeft = (int)(header.targetTime - currentTime); + if (timeLeft <= 0) { + header.y = header.targetY; + header.visible = header.targetVisible; + header.animating = false; + } else { + header.y = header.targetY + (header.sourceY - header.targetY) * timeLeft + / mAnimationDuration; + } + } + if (header.visible) { + View view = header.view; + int saveCount = canvas.save(); + canvas.translate(isLayoutRtl() ? + getWidth() - mHeaderPaddingStart - mHeaderWidth : mHeaderPaddingStart, + header.y); + if (header.state == FADING) { + mBounds.set(0, 0, mHeaderWidth, view.getHeight()); + canvas.saveLayerAlpha(mBounds, header.alpha, Canvas.ALL_SAVE_FLAG); + } + view.draw(canvas); + canvas.restoreToCount(saveCount); + } + } + + /** + * Note: this is a reimplementation of View.isLayoutRtl() since that is currently hidden api. + */ + public boolean isLayoutRtl() { + return (getLayoutDirection() == LAYOUT_DIRECTION_RTL); + } +} |