Updating fast scrollbar UI in Landscape

Creating a separate view for FastScrollBar and moving all the relavant logic in
the view.
For protrait, the touch handling is delegated by the recycler view just like before.
For landscape, the dcrollbar does not overlay with recyclerView and handles the touch
itself

Bug: 37015359
Change-Id: Ie1981326457ba739bdf0ac8063db1065f395f133

1 files changed, 21 insertions, 95 deletions

diff --git a/src/com/android/launcher3/BaseRecyclerView.java b/src/com/android/launcher3/BaseRecyclerView.java
index 84358ea37..3ee6e51b8 100644
--- a/src/com/android/launcher3/BaseRecyclerView.java
+++ b/src/com/android/launcher3/BaseRecyclerView.java
@@ -22,8 +22,9 @@ import android.support.v7.widget.RecyclerView;
 import android.util.AttributeSet;
 import android.view.MotionEvent;
 import android.view.ViewGroup;
+import android.widget.TextView;
 
-import com.android.launcher3.util.Thunk;
+import com.android.launcher3.views.RecyclerViewFastScroller;
 
 
 /**
@@ -36,19 +37,7 @@ import com.android.launcher3.util.Thunk;
 public abstract class BaseRecyclerView extends RecyclerView
         implements RecyclerView.OnItemTouchListener {
 
-    private static final int SCROLL_DELTA_THRESHOLD_DP = 4;
-
-    /** Keeps the last known scrolling delta/velocity along y-axis. */
-    @Thunk int mDy = 0;
-    private float mDeltaThreshold;
-
-    protected final BaseRecyclerViewFastScrollBar mScrollbar;
-
-    private int mDownX;
-    private int mDownY;
-    private int mLastY;
-
-    private boolean mScrollBarVisible = true;
+    protected RecyclerViewFastScroller mScrollbar;
 
     public BaseRecyclerView(Context context) {
         this(context, null);
@@ -60,28 +49,6 @@ public abstract class BaseRecyclerView extends RecyclerView
 
     public BaseRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
-        mDeltaThreshold = getResources().getDisplayMetrics().density * SCROLL_DELTA_THRESHOLD_DP;
-        mScrollbar = new BaseRecyclerViewFastScrollBar(this, getResources());
-
-        ScrollListener listener = new ScrollListener();
-        setOnScrollListener(listener);
-    }
-
-    private class ScrollListener extends OnScrollListener {
-        public ScrollListener() {
-            // Do nothing
-        }
-
-        @Override
-        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
-            mDy = dy;
-
-            // TODO(winsonc): If we want to animate the section heads while scrolling, we can
-            //                initiate that here if the recycler view scroll state is not
-            //                RecyclerView.SCROLL_STATE_IDLE.
-
-            onUpdateScrollbar(dy);
-        }
     }
 
     @Override
@@ -93,7 +60,9 @@ public abstract class BaseRecyclerView extends RecyclerView
     @Override
     protected void onAttachedToWindow() {
         super.onAttachedToWindow();
-        mScrollbar.setPopupView(((ViewGroup) getParent()).findViewById(R.id.fast_scroller_popup));
+        ViewGroup parent = (ViewGroup) getParent();
+        mScrollbar = parent.findViewById(R.id.fast_scroller);
+        mScrollbar.setRecyclerView(this, (TextView) parent.findViewById(R.id.fast_scroller_popup));
     }
 
     /**
@@ -115,32 +84,15 @@ public abstract class BaseRecyclerView extends RecyclerView
      * it is already showing).
      */
     private boolean handleTouchEvent(MotionEvent ev) {
-        ev.offsetLocation(0, -getPaddingTop());
-        int action = ev.getAction();
-        int x = (int) ev.getX();
-        int y = (int) ev.getY();
-        switch (action) {
-            case MotionEvent.ACTION_DOWN:
-                // Keep track of the down positions
-                mDownX = x;
-                mDownY = mLastY = y;
-                if (shouldStopScroll(ev)) {
-                    stopScroll();
-                }
-                mScrollbar.handleTouchEvent(ev, mDownX, mDownY, mLastY);
-                break;
-            case MotionEvent.ACTION_MOVE:
-                mLastY = y;
-                mScrollbar.handleTouchEvent(ev, mDownX, mDownY, mLastY);
-                break;
-            case MotionEvent.ACTION_UP:
-            case MotionEvent.ACTION_CANCEL:
-                onFastScrollCompleted();
-                mScrollbar.handleTouchEvent(ev, mDownX, mDownY, mLastY);
-                break;
+        // Move to mScrollbar's coordinate system.
+        int left = getLeft() - mScrollbar.getLeft();
+        int top = getTop() - mScrollbar.getTop();
+        ev.offsetLocation(left, top);
+        try {
+            return mScrollbar.handleTouchEvent(ev);
+        } finally {
+            ev.offsetLocation(-left, -top);
         }
-        ev.offsetLocation(0, getPaddingTop());
-        return mScrollbar.isDraggingThumb();
     }
 
     public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {
@@ -148,24 +100,9 @@ public abstract class BaseRecyclerView extends RecyclerView
     }
 
     /**
-     * Returns whether this {@link MotionEvent} should trigger the scroll to be stopped.
-     */
-    protected boolean shouldStopScroll(MotionEvent ev) {
-        if (ev.getAction() == MotionEvent.ACTION_DOWN) {
-            if ((Math.abs(mDy) < mDeltaThreshold &&
-                    getScrollState() != RecyclerView.SCROLL_STATE_IDLE)) {
-                // now the touch events are being passed to the {@link WidgetCell} until the
-                // touch sequence goes over the touch slop.
-                return true;
-            }
-        }
-        return false;
-    }
-
-    /**
      * Returns the height of the fast scroll bar
      */
-    protected int getScrollbarTrackHeight() {
+    public int getScrollbarTrackHeight() {
         return getHeight() - getPaddingTop() - getPaddingBottom();
     }
 
@@ -187,25 +124,14 @@ public abstract class BaseRecyclerView extends RecyclerView
     /**
      * Returns the scrollbar for this recycler view.
      */
-    public BaseRecyclerViewFastScrollBar getScrollBar() {
+    public RecyclerViewFastScroller getScrollBar() {
         return mScrollbar;
     }
 
     @Override
     protected void dispatchDraw(Canvas canvas) {
+        onUpdateScrollbar(0);
         super.dispatchDraw(canvas);
-        if (mScrollBarVisible) {
-            onUpdateScrollbar(0);
-            mScrollbar.draw(canvas);
-        }
-    }
-
-    /**
-     * Sets the scrollbar visibility. The call does not refresh the UI, its the responsibility
-     * of the caller to call {@link #invalidate()}.
-     */
-    public void setScrollBarVisible(boolean visible) {
-        mScrollBarVisible = visible;
     }
 
     /**
@@ -236,7 +162,7 @@ public abstract class BaseRecyclerView extends RecyclerView
     /**
      * @return whether fast scrolling is supported in the current state.
      */
-    protected boolean supportsFastScrolling() {
+    public boolean supportsFastScrolling() {
         return true;
     }
 
@@ -252,16 +178,16 @@ public abstract class BaseRecyclerView extends RecyclerView
      * Maps the touch (from 0..1) to the adapter position that should be visible.
      * <p>Override in each subclass of this base class.
      */
-    protected abstract String scrollToPositionAtProgress(float touchFraction);
+    public abstract String scrollToPositionAtProgress(float touchFraction);
 
     /**
      * Updates the bounds for the scrollbar.
      * <p>Override in each subclass of this base class.
      */
-    protected abstract void onUpdateScrollbar(int dy);
+    public abstract void onUpdateScrollbar(int dy);
 
     /**
      * <p>Override in each subclass of this base class.
      */
-    protected void onFastScrollCompleted() {}
+    public void onFastScrollCompleted() {}
 }
\ No newline at end of file