src/com/android/launcher3/BaseRecyclerViewFastScrollBar.java - platform/packages/apps/Launcher3 - Git at Google

 /*
  * 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);
         mRv.invalidate(mTmpRect);
     }

     public int getThumbOffsetY() {
         return mThumbOffsetY;
     }

     private void setTrackWidth(int width) {
         if (mWidth == width) {
             return;
         }
         int left = getDrawLeft();
         // Invalidate the whole scroll bar area.
         mRv.invalidate(left, 0, left + mMaxWidth, 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);
         }
         // 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);
     }
 }
	/*
	* 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);
	mRv.invalidate(mTmpRect);
	}

	public int getThumbOffsetY() {
	return mThumbOffsetY;
	}

	private void setTrackWidth(int width) {
	if (mWidth == width) {
	return;
	}
	int left = getDrawLeft();
	// Invalidate the whole scroll bar area.
	mRv.invalidate(left, 0, left + mMaxWidth, 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);
	}
	// 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);
	}
	}