[Divider] Allow divider drag handle overlay on primary container

Adjust the computation of the divider surface bounds so that the drag
handle can be placed on top of the primary container when the divider
width is less than the drag handle size.

Bug: 327067596
Test: atest DividerPresenterTest
Change-Id: I71fd03a0e7351a68585d2cd30077a8a26adea752

1 files changed, 66 insertions, 15 deletions

diff --git a/libs/WindowManager/Jetpack/src/androidx/window/extensions/embedding/DividerPresenter.java b/libs/WindowManager/Jetpack/src/androidx/window/extensions/embedding/DividerPresenter.java
index a0d6fce4c39b..cded27eec240 100644
--- a/libs/WindowManager/Jetpack/src/androidx/window/extensions/embedding/DividerPresenter.java
+++ b/libs/WindowManager/Jetpack/src/androidx/window/extensions/embedding/DividerPresenter.java
@@ -439,10 +439,6 @@ class DividerPresenter implements View.OnTouchListener {
         }
 
         if (dividerAttributes.getDividerType() == DividerAttributes.DIVIDER_TYPE_DRAGGABLE) {
-            // Draggable divider width must be larger than the drag handle size.
-            widthDp = Math.max(widthDp,
-                    getDimensionDp(R.dimen.activity_embedding_divider_touch_target_width));
-
             // Update minRatio and maxRatio only when it is a draggable divider.
             if (minRatio == RATIO_SYSTEM_DEFAULT) {
                 minRatio = DEFAULT_MIN_RATIO;
@@ -877,17 +873,21 @@ class DividerPresenter implements View.OnTouchListener {
         @NonNull
         private final FrameLayout mDividerLayout;
         @NonNull
+        private final View mDividerLine;
+        private View mDragHandle;
+        @NonNull
         private final View.OnTouchListener mListener;
         @NonNull
         private Properties mProperties;
         private int mDividerWidthPx;
+        private int mHandleWidthPx;
         @Nullable
         private SurfaceControl mPrimaryVeil;
         @Nullable
         private SurfaceControl mSecondaryVeil;
         private boolean mIsDragging;
         private int mDividerPosition;
-        private View mDragHandle;
+        private int mDividerSurfaceWidthPx;
 
         private Renderer(@NonNull Properties properties, @NonNull View.OnTouchListener listener) {
             mProperties = properties;
@@ -905,6 +905,7 @@ class DividerPresenter implements View.OnTouchListener {
                     context, displayManager.getDisplay(mProperties.mDisplayId),
                     mWindowlessWindowManager, "DividerContainer");
             mDividerLayout = new FrameLayout(context);
+            mDividerLine = new View(context);
 
             update();
         }
@@ -921,6 +922,17 @@ class DividerPresenter implements View.OnTouchListener {
             mDividerWidthPx = getDividerWidthPx(mProperties.mDividerAttributes);
             mDividerPosition = mProperties.mInitialDividerPosition;
             mWindowlessWindowManager.setConfiguration(mProperties.mConfiguration);
+
+            if (mProperties.mDividerAttributes.getDividerType()
+                    == DividerAttributes.DIVIDER_TYPE_DRAGGABLE) {
+                // TODO(b/329193115) support divider on secondary display
+                final Context context = ActivityThread.currentActivityThread().getApplication();
+                mHandleWidthPx = context.getResources().getDimensionPixelSize(
+                        R.dimen.activity_embedding_divider_touch_target_width);
+            } else {
+                mHandleWidthPx = 0;
+            }
+
             // TODO handle synchronization between surface transactions and WCT.
             final SurfaceControl.Transaction t = new SurfaceControl.Transaction();
             updateSurface(t);
@@ -950,13 +962,45 @@ class DividerPresenter implements View.OnTouchListener {
          */
         private void updateSurface(@NonNull SurfaceControl.Transaction t) {
             final Rect taskBounds = mProperties.mConfiguration.windowConfiguration.getBounds();
+
+            int dividerSurfacePosition;
+            if (mProperties.mDividerAttributes.getDividerType()
+                    == DividerAttributes.DIVIDER_TYPE_DRAGGABLE) {
+                // When the divider drag handle width is larger than the divider width, the position
+                // of the divider surface is adjusted so that it is large enough to host both the
+                // divider line and the divider drag handle.
+                mDividerSurfaceWidthPx = Math.max(mDividerWidthPx, mHandleWidthPx);
+                dividerSurfacePosition =
+                        mProperties.mIsReversedLayout
+                                ? mDividerPosition
+                                : mDividerPosition + mDividerWidthPx - mDividerSurfaceWidthPx;
+                dividerSurfacePosition = Math.clamp(dividerSurfacePosition, 0,
+                        mProperties.mIsVerticalSplit ? taskBounds.width() : taskBounds.height());
+            } else {
+                mDividerSurfaceWidthPx = mDividerWidthPx;
+                dividerSurfacePosition = mDividerPosition;
+            }
+
             if (mProperties.mIsVerticalSplit) {
-                t.setPosition(mDividerSurface, mDividerPosition, 0.0f);
-                t.setWindowCrop(mDividerSurface, mDividerWidthPx, taskBounds.height());
+                t.setPosition(mDividerSurface, dividerSurfacePosition, 0.0f);
+                t.setWindowCrop(mDividerSurface, mDividerSurfaceWidthPx, taskBounds.height());
             } else {
-                t.setPosition(mDividerSurface, 0.0f, mDividerPosition);
-                t.setWindowCrop(mDividerSurface, taskBounds.width(), mDividerWidthPx);
+                t.setPosition(mDividerSurface, 0.0f, dividerSurfacePosition);
+                t.setWindowCrop(mDividerSurface, taskBounds.width(), mDividerSurfaceWidthPx);
             }
+
+            // Update divider line position in the surface
+            if (!mProperties.mIsReversedLayout) {
+                final int offset = mDividerPosition - dividerSurfacePosition;
+                mDividerLine.setX(mProperties.mIsVerticalSplit ? offset : 0);
+                mDividerLine.setY(mProperties.mIsVerticalSplit ? 0 : offset);
+            } else {
+                // For reversed layout, the divider line is always at the start of the divider
+                // surface.
+                mDividerLine.setX(0);
+                mDividerLine.setY(0);
+            }
+
             if (mIsDragging) {
                 updateVeils(t);
             }
@@ -971,14 +1015,14 @@ class DividerPresenter implements View.OnTouchListener {
             final Rect taskBounds = mProperties.mConfiguration.windowConfiguration.getBounds();
             final WindowManager.LayoutParams lp = mProperties.mIsVerticalSplit
                     ? new WindowManager.LayoutParams(
-                            mDividerWidthPx,
+                            mDividerSurfaceWidthPx,
                             taskBounds.height(),
                             TYPE_APPLICATION_PANEL,
                             FLAG_NOT_FOCUSABLE | FLAG_NOT_TOUCH_MODAL | FLAG_SLIPPERY,
                             PixelFormat.TRANSLUCENT)
                     : new WindowManager.LayoutParams(
                             taskBounds.width(),
-                            mDividerWidthPx,
+                            mDividerSurfaceWidthPx,
                             TYPE_APPLICATION_PANEL,
                             FLAG_NOT_FOCUSABLE | FLAG_NOT_TOUCH_MODAL | FLAG_SLIPPERY,
                             PixelFormat.TRANSLUCENT);
@@ -995,12 +1039,19 @@ class DividerPresenter implements View.OnTouchListener {
          */
         private void updateDivider(@NonNull SurfaceControl.Transaction t) {
             mDividerLayout.removeAllViews();
-            if (mProperties.mIsDraggableExpandType) {
+            mDividerLayout.addView(mDividerLine);
+            if (mProperties.mIsDraggableExpandType && !mIsDragging) {
                 // If a container is fully expanded, the divider overlays on the expanded container.
-                mDividerLayout.setBackgroundColor(Color.TRANSPARENT);
+                mDividerLine.setBackgroundColor(Color.TRANSPARENT);
             } else {
-                mDividerLayout.setBackgroundColor(mProperties.mDividerAttributes.getDividerColor());
+                mDividerLine.setBackgroundColor(mProperties.mDividerAttributes.getDividerColor());
             }
+            final Rect taskBounds = mProperties.mConfiguration.windowConfiguration.getBounds();
+            mDividerLine.setLayoutParams(
+                    mProperties.mIsVerticalSplit
+                            ? new FrameLayout.LayoutParams(mDividerWidthPx, taskBounds.height())
+                            : new FrameLayout.LayoutParams(taskBounds.width(), mDividerWidthPx)
+            );
             if (mProperties.mDividerAttributes.getDividerType()
                     == DividerAttributes.DIVIDER_TYPE_DRAGGABLE) {
                 createVeils();
@@ -1027,7 +1078,7 @@ class DividerPresenter implements View.OnTouchListener {
                                     R.dimen.activity_embedding_divider_touch_target_width));
             params.gravity = Gravity.CENTER;
             button.setLayoutParams(params);
-            button.setBackgroundColor(R.color.transparent);
+            button.setBackgroundColor(Color.TRANSPARENT);
 
             final Drawable handle = context.getResources().getDrawable(
                     R.drawable.activity_embedding_divider_handle, context.getTheme());