Add some egregious back exclusion rects

- Don't allow back gesture at all whenever we hid back button before
- Exclude RecyclerViewFastScroller thumb rect

Bug: 129297464
Change-Id: I40a33697592b02619218c18d1b3def7c3c203f56

quickstep/src/com/android/launcher3/uioverrides/UiFactory.java

@@ -42,7 +42,6 @@ import com.android.launcher3.LauncherStateManager;
 import com.android.launcher3.LauncherStateManager.StateHandler;
 import com.android.launcher3.QuickstepAppTransitionManagerImpl;
 import com.android.launcher3.Utilities;
-import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.dragndrop.DragLayer;
 import com.android.quickstep.OverviewInteractionState;
 import com.android.quickstep.RecentsModel;
@@ -87,6 +86,9 @@ public class UiFactory extends RecentsUiFactory {
         }
         OverviewInteractionState.INSTANCE.get(launcher)
                 .setBackButtonAlpha(shouldBackButtonBeHidden ? 0 : 1, true /* animate */);
+        if (launcher != null && launcher.getDragLayer() != null) {
+            launcher.getDragLayer().setDisallowBackGesture(shouldBackButtonBeHidden);
+        }
     }
 
     public static void onCreate(Launcher launcher) {

src/com/android/launcher3/dragndrop/DragLayer.java

@@ -24,10 +24,12 @@ import android.animation.AnimatorListenerAdapter;
 import android.animation.TimeInterpolator;
 import android.animation.ValueAnimator;
 import android.animation.ValueAnimator.AnimatorUpdateListener;
+import android.annotation.TargetApi;
 import android.content.Context;
 import android.content.res.Resources;
 import android.graphics.Canvas;
 import android.graphics.Rect;
+import android.os.Build;
 import android.util.AttributeSet;
 import android.view.KeyEvent;
 import android.view.MotionEvent;
@@ -43,6 +45,7 @@ import com.android.launcher3.DropTargetBar;
 import com.android.launcher3.Launcher;
 import com.android.launcher3.R;
 import com.android.launcher3.ShortcutAndWidgetContainer;
+import com.android.launcher3.Utilities;
 import com.android.launcher3.Workspace;
 import com.android.launcher3.anim.Interpolators;
 import com.android.launcher3.folder.Folder;
@@ -54,6 +57,8 @@ import com.android.launcher3.util.Thunk;
 import com.android.launcher3.views.BaseDragLayer;
 
 import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 
 /**
  * A ViewGroup that coordinates dragging across its descendants
@@ -68,6 +73,9 @@ public class DragLayer extends BaseDragLayer<Launcher> {
     public static final int ANIMATION_END_DISAPPEAR = 0;
     public static final int ANIMATION_END_REMAIN_VISIBLE = 2;
 
+    private static final List<Rect> SYSTEM_GESTURE_EXCLUSION_RECT =
+            Collections.singletonList(new Rect());
+
     @Thunk DragController mDragController;
 
     // Variables relating to animation of views after drop
@@ -86,6 +94,8 @@ public class DragLayer extends BaseDragLayer<Launcher> {
     private final ViewGroupFocusHelper mFocusIndicatorHelper;
     private final WorkspaceAndHotseatScrim mScrim;
 
+    private boolean mDisallowBackGesture;
+
     /**
      * Used to create a new DragLayer from XML.
      *
@@ -552,6 +562,24 @@ public class DragLayer extends BaseDragLayer<Launcher> {
         mScrim.onInsetsChanged(insets);
     }
 
+    @Override
+    protected void onLayout(boolean changed, int l, int t, int r, int b) {
+        super.onLayout(changed, l, t, r, b);
+        SYSTEM_GESTURE_EXCLUSION_RECT.get(0).set(l, t, r, b);
+        setDisallowBackGesture(mDisallowBackGesture);
+    }
+
+    @TargetApi(Build.VERSION_CODES.Q)
+    public void setDisallowBackGesture(boolean disallowBackGesture) {
+        if (!Utilities.ATLEAST_Q) {
+            return;
+        }
+        mDisallowBackGesture = disallowBackGesture;
+        setSystemGestureExclusionRects(mDisallowBackGesture
+                ? SYSTEM_GESTURE_EXCLUSION_RECT
+                : Collections.emptyList());
+    }
+
     public WorkspaceAndHotseatScrim getScrim() {
         return mScrim;
     }

src/com/android/launcher3/views/RecyclerViewFastScroller.java

@@ -24,6 +24,7 @@ import android.graphics.Canvas;
 import android.graphics.Paint;
 import android.graphics.Point;
 import android.graphics.Rect;
+import android.graphics.RectF;
 import android.util.AttributeSet;
 import android.util.Property;
 import android.view.MotionEvent;
@@ -31,13 +32,16 @@ import android.view.View;
 import android.view.ViewConfiguration;
 import android.widget.TextView;
 
+import androidx.recyclerview.widget.RecyclerView;
+
 import com.android.launcher3.BaseRecyclerView;
 import com.android.launcher3.R;
 import com.android.launcher3.Utilities;
 import com.android.launcher3.graphics.FastScrollThumbDrawable;
 import com.android.launcher3.util.Themes;
 
-import androidx.recyclerview.widget.RecyclerView;
+import java.util.Collections;
+import java.util.List;
 
 /**
  * The track and scrollbar that shows when you scroll the list.
@@ -65,6 +69,9 @@ public class RecyclerViewFastScroller extends View {
     private final static int SCROLL_BAR_VIS_DURATION = 150;
     private static final float FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR = 0.75f;
 
+    private static final List<Rect> SYSTEM_GESTURE_EXCLUSION_RECT =
+            Collections.singletonList(new Rect());
+
     private final int mMinWidth;
     private final int mMaxWidth;
     private final int mThumbPadding;
@@ -81,6 +88,8 @@ public class RecyclerViewFastScroller extends View {
 
     private final Paint mThumbPaint;
     protected final int mThumbHeight;
+    private final RectF mThumbBounds = new RectF();
+    private final Point mThumbDrawOffset = new Point();
 
     private final Paint mTrackPaint;
 
@@ -292,15 +301,23 @@ public class RecyclerViewFastScroller extends View {
         }
         int saveCount = canvas.save();
         canvas.translate(getWidth() / 2, mRv.getScrollBarTop());
+        mThumbDrawOffset.set(getWidth() / 2, mRv.getScrollBarTop());
         // Draw the track
         float halfW = mWidth / 2;
         canvas.drawRoundRect(-halfW, 0, halfW, mRv.getScrollbarTrackHeight(),
                 mWidth, mWidth, mTrackPaint);
 
         canvas.translate(0, mThumbOffsetY);
+        mThumbDrawOffset.y += mThumbOffsetY;
         halfW += mThumbPadding;
         float r = getScrollThumbRadius();
-        canvas.drawRoundRect(-halfW, 0, halfW, mThumbHeight, r, r, mThumbPaint);
+        mThumbBounds.set(-halfW, 0, halfW, mThumbHeight);
+        canvas.drawRoundRect(mThumbBounds, r, r, mThumbPaint);
+        if (Utilities.ATLEAST_Q) {
+            mThumbBounds.roundOut(SYSTEM_GESTURE_EXCLUSION_RECT.get(0));
+            SYSTEM_GESTURE_EXCLUSION_RECT.get(0).offset(mThumbDrawOffset.x, mThumbDrawOffset.y);
+            setSystemGestureExclusionRects(SYSTEM_GESTURE_EXCLUSION_RECT);
+        }
         canvas.restoreToCount(saveCount);
     }