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/*
* Copyright (C) 2015 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.ObjectAnimator;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Rect;
import android.util.Property;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.widget.TextView;
import com.android.launcher3.config.FeatureFlags;
import com.android.launcher3.util.Themes;
/**
* The track and scrollbar that shows when you scroll the list.
*/
public class BaseRecyclerViewFastScrollBar {
private static final Property<BaseRecyclerViewFastScrollBar, Integer> TRACK_WIDTH =
new Property<BaseRecyclerViewFastScrollBar, Integer>(Integer.class, "width") {
@Override
public Integer get(BaseRecyclerViewFastScrollBar scrollBar) {
return scrollBar.mWidth;
}
@Override
public void set(BaseRecyclerViewFastScrollBar scrollBar, Integer value) {
scrollBar.setTrackWidth(value);
}
};
private final static int MAX_TRACK_ALPHA = 30;
private final static int SCROLL_BAR_VIS_DURATION = 150;
private static final float FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR = 1.5f;
private final Rect mTmpRect = new Rect();
private final BaseRecyclerView mRv;
private final boolean mIsRtl;
// The inset is the buffer around which a point will still register as a click on the scrollbar
private final int mTouchInset;
private final int mMinWidth;
private final int mMaxWidth;
// Current width of the track
private int mWidth;
private ObjectAnimator mWidthAnimator;
private final Path mThumbPath = new Path();
private final Paint mThumbPaint;
private final int mThumbHeight;
private final Paint mTrackPaint;
private float mLastTouchY;
private boolean mIsDragging;
private boolean mIsThumbDetached;
private boolean mCanThumbDetach;
private boolean mIgnoreDragGesture;
// This is the offset from the top of the scrollbar when the user first starts touching. To
// prevent jumping, this offset is applied as the user scrolls.
private int mTouchOffsetY;
private int mThumbOffsetY;
// Fast scroller popup
private TextView mPopupView;
private boolean mPopupVisible;
private String mPopupSectionName;
public BaseRecyclerViewFastScrollBar(BaseRecyclerView rv, Resources res) {
mRv = rv;
mTrackPaint = new Paint();
mTrackPaint.setColor(rv.getFastScrollerTrackColor(Color.BLACK));
mTrackPaint.setAlpha(MAX_TRACK_ALPHA);
mThumbPaint = new Paint();
mThumbPaint.setAntiAlias(true);
mThumbPaint.setColor(Themes.getColorAccent(rv.getContext()));
mThumbPaint.setStyle(Paint.Style.FILL);
mWidth = mMinWidth = res.getDimensionPixelSize(R.dimen.container_fastscroll_thumb_min_width);
mMaxWidth = res.getDimensionPixelSize(R.dimen.container_fastscroll_thumb_max_width);
mThumbHeight = res.getDimensionPixelSize(R.dimen.container_fastscroll_thumb_height);
mTouchInset = res.getDimensionPixelSize(R.dimen.container_fastscroll_thumb_touch_inset);
mIsRtl = Utilities.isRtl(res);
updateThumbPath();
}
public void setPopupView(View popup) {
mPopupView = (TextView) popup;
}
public void setDetachThumbOnFastScroll() {
mCanThumbDetach = true;
}
public void reattachThumbToScroll() {
mIsThumbDetached = false;
}
private int getDrawLeft() {
return mIsRtl ? 0 : (mRv.getWidth() - mMaxWidth);
}
public void setThumbOffsetY(int y) {
if (mThumbOffsetY == y) {
return;
}
// Invalidate the previous and new thumb area
int drawLeft = getDrawLeft();
mTmpRect.set(drawLeft, mThumbOffsetY, drawLeft + mMaxWidth, mThumbOffsetY + mThumbHeight);
mThumbOffsetY = y;
mTmpRect.union(drawLeft, mThumbOffsetY, drawLeft + mMaxWidth, mThumbOffsetY + mThumbHeight);
mTmpRect.offset(0, mRv.getPaddingTop());
mRv.invalidate(mTmpRect);
}
public int getThumbOffsetY() {
return mThumbOffsetY;
}
private void setTrackWidth(int width) {
if (mWidth == width) {
return;
}
int left = getDrawLeft();
int top = mRv.getPaddingTop();
// Invalidate the whole scroll bar area.
mRv.invalidate(left, top, left + mMaxWidth, top + mRv.getScrollbarTrackHeight());
mWidth = width;
updateThumbPath();
}
/**
* Updates the path for the thumb drawable.
*/
private void updateThumbPath() {
int smallWidth = mIsRtl ? mWidth : -mWidth;
int largeWidth = mIsRtl ? mMaxWidth : -mMaxWidth;
mThumbPath.reset();
mThumbPath.moveTo(0, 0);
mThumbPath.lineTo(0, mThumbHeight); // Left edge
mThumbPath.lineTo(smallWidth, mThumbHeight); // bottom edge
mThumbPath.cubicTo(smallWidth, mThumbHeight, // right edge
largeWidth, mThumbHeight / 2,
smallWidth, 0);
mThumbPath.close();
}
public int getThumbHeight() {
return mThumbHeight;
}
public boolean isDraggingThumb() {
return mIsDragging;
}
public boolean isThumbDetached() {
return mIsThumbDetached;
}
/**
* Handles the touch event and determines whether to show the fast scroller (or updates it if
* it is already showing).
*/
public void handleTouchEvent(MotionEvent ev, int downX, int downY, int lastY) {
ViewConfiguration config = ViewConfiguration.get(mRv.getContext());
int action = ev.getAction();
int y = (int) ev.getY();
switch (action) {
case MotionEvent.ACTION_DOWN:
if (isNearThumb(downX, downY)) {
mTouchOffsetY = downY - mThumbOffsetY;
} else if (FeatureFlags.LAUNCHER3_DIRECT_SCROLL
&& mRv.supportsFastScrolling()
&& isNearScrollBar(downX)) {
calcTouchOffsetAndPrepToFastScroll(downY, lastY);
updateFastScrollSectionNameAndThumbOffset(lastY, y);
}
break;
case MotionEvent.ACTION_MOVE:
// Check if we should start scrolling, but ignore this fastscroll gesture if we have
// exceeded some fixed movement
mIgnoreDragGesture |= Math.abs(y - downY) > config.getScaledPagingTouchSlop();
if (!mIsDragging && !mIgnoreDragGesture && mRv.supportsFastScrolling() &&
isNearThumb(downX, lastY) &&
Math.abs(y - downY) > config.getScaledTouchSlop()) {
calcTouchOffsetAndPrepToFastScroll(downY, lastY);
}
if (mIsDragging) {
updateFastScrollSectionNameAndThumbOffset(lastY, y);
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
mTouchOffsetY = 0;
mLastTouchY = 0;
mIgnoreDragGesture = false;
if (mIsDragging) {
mIsDragging = false;
animatePopupVisibility(false);
showActiveScrollbar(false);
}
break;
}
}
private void calcTouchOffsetAndPrepToFastScroll(int downY, int lastY) {
mRv.getParent().requestDisallowInterceptTouchEvent(true);
mIsDragging = true;
if (mCanThumbDetach) {
mIsThumbDetached = true;
}
mTouchOffsetY += (lastY - downY);
animatePopupVisibility(true);
showActiveScrollbar(true);
}
private void updateFastScrollSectionNameAndThumbOffset(int lastY, int y) {
// Update the fastscroller section name at this touch position
int bottom = mRv.getScrollbarTrackHeight() - mThumbHeight;
float boundedY = (float) Math.max(0, Math.min(bottom, y - mTouchOffsetY));
String sectionName = mRv.scrollToPositionAtProgress(boundedY / bottom);
if (!sectionName.equals(mPopupSectionName)) {
mPopupSectionName = sectionName;
mPopupView.setText(sectionName);
}
animatePopupVisibility(!sectionName.isEmpty());
updatePopupY(lastY);
mLastTouchY = boundedY;
setThumbOffsetY((int) mLastTouchY);
}
public void draw(Canvas canvas) {
if (mThumbOffsetY < 0) {
return;
}
int saveCount = canvas.save(Canvas.MATRIX_SAVE_FLAG);
if (!mIsRtl) {
canvas.translate(mRv.getWidth(), 0);
}
canvas.translate(0, mRv.getPaddingTop());
// Draw the track
int thumbWidth = mIsRtl ? mWidth : -mWidth;
canvas.drawRect(0, 0, thumbWidth, mRv.getScrollbarTrackHeight(), mTrackPaint);
canvas.translate(0, mThumbOffsetY);
canvas.drawPath(mThumbPath, mThumbPaint);
canvas.restoreToCount(saveCount);
}
/**
* Animates the width of the scrollbar.
*/
private void showActiveScrollbar(boolean isScrolling) {
if (mWidthAnimator != null) {
mWidthAnimator.cancel();
}
mWidthAnimator = ObjectAnimator.ofInt(this, TRACK_WIDTH,
isScrolling ? mMaxWidth : mMinWidth);
mWidthAnimator.setDuration(SCROLL_BAR_VIS_DURATION);
mWidthAnimator.start();
}
/**
* Returns whether the specified point is inside the thumb bounds.
*/
public boolean isNearThumb(int x, int y) {
int left = getDrawLeft();
mTmpRect.set(left, mThumbOffsetY, left + mMaxWidth, mThumbOffsetY + mThumbHeight);
mTmpRect.inset(mTouchInset, mTouchInset);
return mTmpRect.contains(x, y);
}
/**
* Returns whether the specified x position is near the scroll bar.
*/
public boolean isNearScrollBar(int x) {
int left = getDrawLeft();
return x >= left && x <= left + mMaxWidth;
}
private void animatePopupVisibility(boolean visible) {
if (mPopupVisible != visible) {
mPopupVisible = visible;
mPopupView.animate().cancel();
mPopupView.animate().alpha(visible ? 1f : 0f).setDuration(visible ? 200 : 150).start();
}
}
private void updatePopupY(int lastTouchY) {
int height = mPopupView.getHeight();
float top = lastTouchY - (FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR * height);
top = Math.max(mMaxWidth, Math.min(top, mRv.getScrollbarTrackHeight() - mMaxWidth - height));
mPopupView.setTranslationY(top);
}
}
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