Visualize view focus in debug mode.

See the bug for motivation.

Bug: 32099818
Test: Manual check with enabling the dev setting.
Change-Id: I77262f77ac709639e5b1314a0be45612bde70ad6

2 files changed, 58 insertions, 22 deletions

diff --git a/core/java/android/view/View.java b/core/java/android/view/View.java
index deb3f90570e3..18530594c693 100644
--- a/core/java/android/view/View.java
+++ b/core/java/android/view/View.java
@@ -40,6 +40,7 @@ import android.content.res.Resources;
 import android.content.res.TypedArray;
 import android.graphics.Bitmap;
 import android.graphics.Canvas;
+import android.graphics.Color;
 import android.graphics.Insets;
 import android.graphics.Interpolator;
 import android.graphics.LinearGradient;
@@ -757,6 +758,9 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
         AccessibilityEventSource {
     private static final boolean DBG = false;
 
+    /** @hide */
+    public static boolean DEBUG_DRAW = false;
+
     /**
      * The logging tag used by this class with android.util.Log.
      */
@@ -1184,6 +1188,8 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
      */
     static final int PARENT_SAVE_DISABLED_MASK = 0x20000000;
 
+    private static Paint sDebugPaint;
+
     /** @hide */
     @IntDef(flag = true,
             value = {
@@ -1655,6 +1661,10 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
             | AccessibilityEvent.TYPE_VIEW_ACCESSIBILITY_FOCUSED
             | AccessibilityEvent.TYPE_VIEW_TEXT_TRAVERSED_AT_MOVEMENT_GRANULARITY;
 
+    static final int DEBUG_CORNERS_COLOR = Color.rgb(63, 127, 255);
+
+    static final int DEBUG_CORNERS_SIZE_DIP = 8;
+
     /**
      * Temporary Rect currently for use in setBackground().  This will probably
      * be extended in the future to hold our own class with more than just
@@ -4743,6 +4753,10 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
         mRenderNode = RenderNode.create(getClass().getName(), this);
     }
 
+    final boolean debugDraw() {
+        return DEBUG_DRAW || mAttachInfo != null && mAttachInfo.mDebugLayout;
+    }
+
     private static SparseArray<String> getAttributeMap() {
         if (mAttributeMap == null) {
             mAttributeMap = new SparseArray<>();
@@ -16137,6 +16151,9 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
                         if (mOverlay != null && !mOverlay.isEmpty()) {
                             mOverlay.getOverlayView().draw(canvas);
                         }
+                        if (debugDraw()) {
+                            debugDrawFocus(canvas);
+                        }
                     } else {
                         draw(canvas);
                     }
@@ -17115,6 +17132,41 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
         return more;
     }
 
+    static Paint getDebugPaint() {
+        if (sDebugPaint == null) {
+            sDebugPaint = new Paint();
+            sDebugPaint.setAntiAlias(false);
+        }
+        return sDebugPaint;
+    }
+
+    final int dipsToPixels(int dips) {
+        float scale = getContext().getResources().getDisplayMetrics().density;
+        return (int) (dips * scale + 0.5f);
+    }
+
+    final private void debugDrawFocus(Canvas canvas) {
+        if (isFocused()) {
+            final int cornerSquareSize = dipsToPixels(DEBUG_CORNERS_SIZE_DIP);
+            final int w = getWidth();
+            final int h = getHeight();
+            final Paint paint = getDebugPaint();
+            paint.setColor(DEBUG_CORNERS_COLOR);
+
+            // Draw squares in corners.
+            paint.setStyle(Paint.Style.FILL);
+            canvas.drawRect(0, 0, cornerSquareSize, cornerSquareSize, paint);
+            canvas.drawRect(w - cornerSquareSize, 0, w, cornerSquareSize, paint);
+            canvas.drawRect(0, h - cornerSquareSize, cornerSquareSize, h, paint);
+            canvas.drawRect(w - cornerSquareSize, h - cornerSquareSize, w, h, paint);
+
+            // Draw big X across the view.
+            paint.setStyle(Paint.Style.STROKE);
+            canvas.drawLine(0, 0, getWidth(), getHeight(), paint);
+            canvas.drawLine(0, getHeight(), getWidth(), 0, paint);
+        }
+    }
+
     /**
      * Manually render this view (and all of its children) to the given Canvas.
      * The view must have already done a full layout before this function is
@@ -17169,6 +17221,10 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
             // Step 6, draw decorations (foreground, scrollbars)
             onDrawForeground(canvas);
 
+            if (debugDraw()) {
+                debugDrawFocus(canvas);
+            }
+
             // we're done...
             return;
         }
diff --git a/core/java/android/view/ViewGroup.java b/core/java/android/view/ViewGroup.java
index 2e428a734331..a7af5e5b5c72 100644
--- a/core/java/android/view/ViewGroup.java
+++ b/core/java/android/view/ViewGroup.java
@@ -116,8 +116,6 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
     private static final String TAG = "ViewGroup";
 
     private static final boolean DBG = false;
-    /** @hide */
-    public static boolean DEBUG_DRAW = false;
 
     /**
      * Views which have been hidden or removed which need to be animated on
@@ -476,7 +474,6 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
     private static final int ARRAY_INITIAL_CAPACITY = 12;
     private static final int ARRAY_CAPACITY_INCREMENT = 12;
 
-    private static Paint sDebugPaint;
     private static float[] sDebugLines;
 
     // Used to draw cached views
@@ -586,10 +583,6 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
         initFromAttributes(context, attrs, defStyleAttr, defStyleRes);
     }
 
-    private boolean debugDraw() {
-        return DEBUG_DRAW || mAttachInfo != null && mAttachInfo.mDebugLayout;
-    }
-
     private void initViewGroup() {
         // ViewGroup doesn't draw by default
         if (!debugDraw()) {
@@ -3375,11 +3368,6 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
         fillRect(c, paint, x1, y1, x1 + lw * sign(dx), y1 + dy);
     }
 
-    private int dipsToPixels(int dips) {
-        float scale = getContext().getResources().getDisplayMetrics().density;
-        return (int) (dips * scale + 0.5f);
-    }
-
     private static void drawRectCorners(Canvas canvas, int x1, int y1, int x2, int y2, Paint paint,
             int lineLength, int lineWidth) {
         drawCorner(canvas, paint, x1, y1, lineLength, lineLength, lineWidth);
@@ -3448,10 +3436,10 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
 
         // Draw clip bounds
         {
-            paint.setColor(Color.rgb(63, 127, 255));
+            paint.setColor(DEBUG_CORNERS_COLOR);
             paint.setStyle(Paint.Style.FILL);
 
-            int lineLength = dipsToPixels(8);
+            int lineLength = dipsToPixels(DEBUG_CORNERS_SIZE_DIP);
             int lineWidth = dipsToPixels(1);
             for (int i = 0; i < getChildCount(); i++) {
                 View c = getChildAt(i);
@@ -7926,14 +7914,6 @@ public abstract class ViewGroup extends View implements ViewParent, ViewManager
         }
     }
 
-    private static Paint getDebugPaint() {
-        if (sDebugPaint == null) {
-            sDebugPaint = new Paint();
-            sDebugPaint.setAntiAlias(false);
-        }
-        return sDebugPaint;
-    }
-
     private static void drawRect(Canvas canvas, Paint paint, int x1, int y1, int x2, int y2) {
         if (sDebugLines== null) {
             // TODO: This won't work with multiple UI threads in a single process