Scribe for View: handwriting initiation for unfocused

Bug: 211763729
Test: atest FrameworksCoreTests:HandwritingInitiatorTest
Test: atest FrameworksCoreTests:HandwritableViewInfoTest
Test: atest FrameworksCoreTests:HandwritingAreaTrackerTest
Test: manually test
Change-Id: Ica9ee82cf1dc41feb5e4ff0f52ee13c1e4de8ad4

core/java/android/view/HandwritingInitiator.java

@@ -24,6 +24,9 @@ import android.view.inputmethod.InputMethodManager;
 import com.android.internal.annotations.VisibleForTesting;
 
 import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
 
 /**
  * Initiates handwriting mode once it detects stylus movement in handwritable areas.
@@ -58,6 +61,7 @@ public class HandwritingInitiator {
     private final long mTapTimeoutInMillis;
 
     private State mState = new State();
+    private final HandwritingAreaTracker mHandwritingAreasTracker = new HandwritingAreaTracker();
 
     /**
      * Helper method to reset the internal state of this class.
@@ -83,8 +87,8 @@ public class HandwritingInitiator {
     private final InputMethodManager mImm;
 
     @VisibleForTesting
-    public HandwritingInitiator(ViewConfiguration viewConfiguration,
-            InputMethodManager inputMethodManager) {
+    public HandwritingInitiator(@NonNull ViewConfiguration viewConfiguration,
+            @NonNull InputMethodManager inputMethodManager) {
         mTouchSlop = viewConfiguration.getScaledTouchSlop();
         mTapTimeoutInMillis = ViewConfiguration.getTapTimeout();
         mImm = inputMethodManager;
@@ -98,7 +102,7 @@ public class HandwritingInitiator {
      * @param motionEvent the stylus MotionEvent.
      */
     @VisibleForTesting
-    public void onTouchEvent(MotionEvent motionEvent) {
+    public void onTouchEvent(@NonNull MotionEvent motionEvent) {
         final int maskedAction = motionEvent.getActionMasked();
         switch (maskedAction) {
             case MotionEvent.ACTION_DOWN:
@@ -151,11 +155,20 @@ public class HandwritingInitiator {
                 final float y = motionEvent.getY(pointerIndex);
                 if (largerThanTouchSlop(x, y, mState.mStylusDownX, mState.mStylusDownY)) {
                     mState.mExceedTouchSlop = true;
-                    tryStartHandwriting();
+                    View candidateView =
+                            findBestCandidateView(mState.mStylusDownX, mState.mStylusDownY);
+                    if (candidateView != null) {
+                        if (candidateView == getConnectedView()) {
+                            startHandwriting(candidateView);
+                        } else {
+                            candidateView.requestFocus();
+                        }
+                    }
                 }
         }
     }
 
+    @Nullable
     private View getConnectedView() {
         if (mConnectedView == null) return null;
         return mConnectedView.get();
@@ -178,13 +191,16 @@ public class HandwritingInitiator {
             clearConnectedView();
             return;
         }
+
         final View connectedView = getConnectedView();
         if (connectedView == view) {
             ++mConnectionCount;
         } else {
             mConnectedView = new WeakReference<>(view);
             mConnectionCount = 1;
-            tryStartHandwriting();
+            if (mState.mShouldInitHandwriting) {
+                tryStartHandwriting();
+            }
         }
     }
 
@@ -233,17 +249,10 @@ public class HandwritingInitiator {
             return;
         }
 
-        final ViewParent viewParent = connectedView.getParent();
-        // Do a final check before startHandwriting.
-        if (viewParent != null && connectedView.isAttachedToWindow()) {
-            final Rect editorBounds =
-                    new Rect(0, 0, connectedView.getWidth(), connectedView.getHeight());
-            if (viewParent.getChildVisibleRect(connectedView, editorBounds, null)) {
-                final int roundedInitX = Math.round(mState.mStylusDownX);
-                final int roundedInitY = Math.round(mState.mStylusDownY);
-                if (editorBounds.contains(roundedInitX, roundedInitY)) {
-                    startHandwriting(connectedView);
-                }
+        Rect handwritingArea = getViewHandwritingArea(connectedView);
+        if (handwritingArea != null) {
+            if (contains(handwritingArea, mState.mStylusDownX, mState.mStylusDownY)) {
+                startHandwriting(connectedView);
             }
         }
         reset();
@@ -251,10 +260,79 @@ public class HandwritingInitiator {
 
     /** For test only. */
     @VisibleForTesting
-    public void startHandwriting(View view) {
+    public void startHandwriting(@NonNull View view) {
         mImm.startStylusHandwriting(view);
     }
 
+    /**
+     * Notify that the handwriting area for the given view might be updated.
+     * @param view the view whose handwriting area might be updated.
+     */
+    public void updateHandwritingAreasForView(@NonNull View view) {
+        mHandwritingAreasTracker.updateHandwritingAreaForView(view);
+    }
+
+    /**
+     * Given the location of the stylus event, return the best candidate view to initialize
+     * handwriting mode.
+     *
+     * @param x the x coordinates of the stylus event, in the coordinates of the window.
+     * @param y the y coordinates of the stylus event, in the coordinates of the window.
+     */
+    @Nullable
+    private View findBestCandidateView(float x, float y) {
+        // If the connectedView is not null and do not set any handwriting area, it will check
+        // whether the connectedView's boundary contains the initial stylus position. If true,
+        // directly return the connectedView.
+        final View connectedView = getConnectedView();
+        if (connectedView != null && connectedView.isAutoHandwritingEnabled()) {
+            final Rect handwritingArea = getViewHandwritingArea(connectedView);
+            if (handwritingArea != null && contains(handwritingArea, x, y)) {
+                return connectedView;
+            }
+        }
+
+        // Check the registered handwriting areas.
+        final List<HandwritableViewInfo> handwritableViewInfos =
+                mHandwritingAreasTracker.computeViewInfos();
+        for (HandwritableViewInfo viewInfo : handwritableViewInfos) {
+            final View view = viewInfo.getView();
+            if (!view.isAutoHandwritingEnabled()) continue;
+            final Rect rect = viewInfo.getHandwritingArea();
+            if (rect != null && contains(rect, x, y)) {
+                return viewInfo.getView();
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Return the handwriting area of the given view, represented in the window's coordinate.
+     * If the view didn't set any handwriting area, it will return the view's boundary.
+     * It will return null if the view or its handwriting area is not visible.
+     */
+    @Nullable
+    private static Rect getViewHandwritingArea(@NonNull View view) {
+        final ViewParent viewParent = view.getParent();
+        if (viewParent != null && view.isAttachedToWindow() && view.isAggregatedVisible()) {
+            Rect handwritingArea = view.getHandwritingArea();
+            if (handwritingArea == null) {
+                handwritingArea = new Rect(0, 0, view.getWidth(), view.getHeight());
+            }
+            if (viewParent.getChildVisibleRect(view, handwritingArea, null)) {
+                return handwritingArea;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Return true if the (x, y) is inside by the given {@link Rect}.
+     */
+    private boolean contains(@NonNull Rect rect, float x, float y) {
+        return x >= rect.left && x < rect.right && y >= rect.top && y < rect.bottom;
+    }
+
     private boolean largerThanTouchSlop(float x1, float y1, float x2, float y2) {
         float dx = x1 - x2;
         float dy = y1 - y2;
@@ -291,4 +369,134 @@ public class HandwritingInitiator {
         private float mStylusDownX = Float.NaN;
         private float mStylusDownY = Float.NaN;
     }
+
+    /** The helper method to check if the given view is still active for handwriting. */
+    private static boolean isViewActive(@Nullable View view) {
+        return view != null && view.isAttachedToWindow() && view.isAggregatedVisible()
+                && view.isAutoHandwritingEnabled();
+    }
+
+    /**
+     * A class used to track the handwriting areas set by the Views.
+     *
+     * @hide
+     */
+    @VisibleForTesting
+    public static class HandwritingAreaTracker {
+        private final List<HandwritableViewInfo> mHandwritableViewInfos;
+
+        public HandwritingAreaTracker() {
+            mHandwritableViewInfos = new ArrayList<>();
+        }
+
+        /**
+         * Notify this tracker that the handwriting area of the given view has been updated.
+         * This method does three things:
+         * a) iterate over the all the tracked ViewInfos and remove those already invalid ones.
+         * b) mark the given view's ViewInfo to be dirty. So that next time when
+         * {@link #computeViewInfos} is called, this view's handwriting area will be recomputed.
+         * c) If no the given view is not in the tracked ViewInfo list, a new ViewInfo object will
+         * be created and added to the list.
+         *
+         * @param view the view whose handwriting area is updated.
+         */
+        public void updateHandwritingAreaForView(@NonNull View view) {
+            Iterator<HandwritableViewInfo> iterator = mHandwritableViewInfos.iterator();
+            boolean found = false;
+            while (iterator.hasNext()) {
+                final HandwritableViewInfo handwritableViewInfo = iterator.next();
+                final View curView = handwritableViewInfo.getView();
+                if (!isViewActive(curView)) {
+                    iterator.remove();
+                }
+                if (curView == view) {
+                    found = true;
+                    handwritableViewInfo.mIsDirty = true;
+                }
+            }
+            if (!found && isViewActive(view)) {
+                // The given view is not tracked. Create a new HandwritableViewInfo for it and add
+                // to the list.
+                mHandwritableViewInfos.add(new HandwritableViewInfo(view));
+            }
+        }
+
+        /**
+         * Update the handwriting areas and return a list of ViewInfos containing the view
+         * reference and its handwriting area.
+         */
+        @NonNull
+        public List<HandwritableViewInfo> computeViewInfos() {
+            mHandwritableViewInfos.removeIf(viewInfo -> !viewInfo.update());
+            return mHandwritableViewInfos;
+        }
+    }
+
+    /**
+     * A class that reference to a View and its handwriting area(in the ViewRoot's coordinate.)
+     *
+     * @hide
+     */
+    @VisibleForTesting
+    public static class HandwritableViewInfo {
+        final WeakReference<View> mViewRef;
+        Rect mHandwritingArea = null;
+        @VisibleForTesting
+        public boolean mIsDirty = true;
+
+        @VisibleForTesting
+        public HandwritableViewInfo(@NonNull View view) {
+            mViewRef = new WeakReference<>(view);
+        }
+
+        /** Return the tracked view. */
+        @Nullable
+        public View getView() {
+            return mViewRef.get();
+        }
+
+        /**
+         * Return the tracked handwriting area, represented in the ViewRoot's coordinates.
+         * Notice, the caller should not modify the returned Rect.
+         */
+        @Nullable
+        public Rect getHandwritingArea() {
+            return mHandwritingArea;
+        }
+
+        /**
+         * Update the handwriting area in this ViewInfo.
+         *
+         * @return true if this ViewInfo is still valid. Or false if this ViewInfo has become
+         * invalid due to either view is no longer visible, or the handwriting area set by the
+         * view is removed. {@link HandwritingAreaTracker} no longer need to keep track of this
+         * HandwritableViewInfo this method returns false.
+         */
+        public boolean update() {
+            final View view = getView();
+            if (!isViewActive(view)) {
+                return false;
+            }
+
+            if (!mIsDirty) {
+                return true;
+            }
+            final Rect localRect = view.getHandwritingArea();
+            if (localRect == null) {
+                return false;
+            }
+
+            ViewParent parent = view.getParent();
+            if (parent != null) {
+                final Rect newRect = new Rect(localRect);
+                if (parent.getChildVisibleRect(view, newRect, null /* offset */)) {
+                    mHandwritingArea = newRect;
+                } else {
+                    mHandwritingArea = null;
+                }
+            }
+            mIsDirty = false;
+            return true;
+        }
+    }
 }

core/java/android/view/View.java

@@ -4745,9 +4745,11 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
         private List<Rect> mSystemGestureExclusionRects = null;
         private List<Rect> mKeepClearRects = null;
         private boolean mPreferKeepClear = false;
+        private Rect mHandwritingArea = null;
 
         /**
-         * Used to track {@link #mSystemGestureExclusionRects} and {@link #mKeepClearRects}
+         * Used to track {@link #mSystemGestureExclusionRects}, {@link #mKeepClearRects} and
+         * {@link #mHandwritingArea}.
          */
         public RenderNode.PositionUpdateListener mPositionUpdateListener;
         private Runnable mPositionChangedUpdate;
@@ -11692,7 +11694,8 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
     private void updatePositionUpdateListener() {
         final ListenerInfo info = getListenerInfo();
         if (getSystemGestureExclusionRects().isEmpty()
-                && collectPreferKeepClearRects().isEmpty()) {
+                && collectPreferKeepClearRects().isEmpty()
+                && (info.mHandwritingArea == null || !isAutoHandwritingEnabled())) {
             if (info.mPositionUpdateListener != null) {
                 mRenderNode.removePositionUpdateListener(info.mPositionUpdateListener);
                 info.mPositionChangedUpdate = null;
@@ -11702,6 +11705,7 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
                 info.mPositionChangedUpdate = () -> {
                     updateSystemGestureExclusionRects();
                     updateKeepClearRects();
+                    updateHandwritingArea();
                 };
                 info.mPositionUpdateListener = new RenderNode.PositionUpdateListener() {
                     @Override
@@ -11857,6 +11861,51 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
         return Collections.emptyList();
     }
 
+    /**
+     * Set a list of handwriting areas in this view. If there is any stylus {@link MotionEvent}
+     * occurs within those areas, it will trigger stylus handwriting mode. This can be disabled by
+     * disabling the auto handwriting initiation by calling
+     * {@link #setAutoHandwritingEnabled(boolean)} with false.
+     *
+     * @attr rects a list of handwriting area in the view's local coordiniates.
+     *
+     * @see android.view.inputmethod.InputMethodManager#startStylusHandwriting(View)
+     * @see #setAutoHandwritingEnabled(boolean)
+     *
+     * @hide
+     */
+    public void setHandwritingArea(@Nullable Rect rect) {
+        final ListenerInfo info = getListenerInfo();
+        info.mHandwritingArea = rect;
+        updatePositionUpdateListener();
+        postUpdate(this::updateHandwritingArea);
+    }
+
+    /**
+     * Return the handwriting areas set on this view, in its local coordinates.
+     * Notice: the caller of this method should not modify the Rect returned.
+     * @see #setHandwritingArea(Rect)
+     *
+     * @hide
+     */
+    @Nullable
+    public Rect getHandwritingArea() {
+        final ListenerInfo info = mListenerInfo;
+        if (info != null) {
+            return info.mHandwritingArea;
+        }
+        return null;
+    }
+
+    void updateHandwritingArea() {
+        // If autoHandwritingArea is not enabled, do nothing.
+        if (!isAutoHandwritingEnabled()) return;
+        final AttachInfo ai = mAttachInfo;
+        if (ai != null) {
+            ai.mViewRootImpl.getHandwritingInitiator().updateHandwritingAreasForView(this);
+        }
+    }
+
     /**
      * Compute the view's coordinate within the surface.
      *
@@ -31154,6 +31203,8 @@ public class View implements Drawable.Callback, KeyEvent.Callback,
         } else {
             mPrivateFlags4 &= ~PFLAG4_AUTO_HANDWRITING_ENABLED;
         }
+        updatePositionUpdateListener();
+        postUpdate(this::updateHandwritingArea);
     }
 
     /**

core/java/android/widget/EditText.java

@@ -17,6 +17,7 @@
 package android.widget;
 
 import android.content.Context;
+import android.graphics.Rect;
 import android.text.Editable;
 import android.text.Selection;
 import android.text.Spannable;
@@ -173,6 +174,12 @@ public class EditText extends TextView {
         return EditText.class.getName();
     }
 
+    @Override
+    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
+        super.onSizeChanged(w, h, oldw, oldh);
+        setHandwritingArea(new Rect(0, 0, w, h));
+    }
+
     /** @hide */
     @Override
     protected boolean supportsAutoSizeText() {

core/tests/coretests/src/android/view/stylus/HandwritableViewInfoTest.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2022 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 android.view.stylus;
+
+import static android.view.stylus.HandwritingTestUtil.createView;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static junit.framework.Assert.assertFalse;
+import static junit.framework.Assert.assertTrue;
+
+import android.graphics.Rect;
+import android.platform.test.annotations.Presubmit;
+import android.view.HandwritingInitiator;
+import android.view.View;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.SmallTest;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@Presubmit
+@SmallTest
+@RunWith(AndroidJUnit4.class)
+public class HandwritableViewInfoTest {
+
+    @Test
+    public void constructorTest() {
+        final Rect rect = new Rect(1, 2, 3, 4);
+        final View view = createView(rect);
+        final HandwritingInitiator.HandwritableViewInfo handwritableViewInfo =
+                new HandwritingInitiator.HandwritableViewInfo(view);
+
+        assertThat(handwritableViewInfo.getView()).isEqualTo(view);
+        // It's labeled dirty by default.
+        assertTrue(handwritableViewInfo.mIsDirty);
+    }
+
+    @Test
+    public void update() {
+        final Rect rect = new Rect(1, 2, 3, 4);
+        final View view = createView(rect);
+        final HandwritingInitiator.HandwritableViewInfo handwritableViewInfo =
+                new HandwritingInitiator.HandwritableViewInfo(view);
+
+        assertThat(handwritableViewInfo.getView()).isEqualTo(view);
+
+        final boolean isViewInfoValid = handwritableViewInfo.update();
+
+        assertTrue(isViewInfoValid);
+        assertThat(handwritableViewInfo.getHandwritingArea()).isEqualTo(rect);
+        assertFalse(handwritableViewInfo.mIsDirty);
+    }
+
+    @Test
+    public void update_viewDisableAutoHandwriting() {
+        final Rect rect = new Rect(1, 2, 3, 4);
+        final View view = HandwritingTestUtil.createView(rect, false /* autoHandwritingEnabled */);
+        final HandwritingInitiator.HandwritableViewInfo handwritableViewInfo =
+                new HandwritingInitiator.HandwritableViewInfo(view);
+
+        assertThat(handwritableViewInfo.getView()).isEqualTo(view);
+
+        final boolean isViewInfoValid = handwritableViewInfo.update();
+
+        // Return false because the view disabled autoHandwriting.
+        assertFalse(isViewInfoValid);
+        // The view disabled the autoHandwriting, and it won't update the handwriting area.
+        assertThat(handwritableViewInfo.getHandwritingArea()).isNull();
+    }
+
+}

core/tests/coretests/src/android/view/stylus/HandwritingAreaTrackerTest.java

@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2022 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 android.view.stylus;
+
+import static android.view.stylus.HandwritingTestUtil.createView;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.app.Instrumentation;
+import android.content.Context;
+import android.graphics.Rect;
+import android.platform.test.annotations.Presubmit;
+import android.view.HandwritingInitiator;
+import android.view.View;
+
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+import androidx.test.filters.SmallTest;
+import androidx.test.platform.app.InstrumentationRegistry;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.List;
+
+
+/**
+ * Tests for {@link HandwritingInitiator.HandwritingAreaTracker}
+ *
+ * Build/Install/Run:
+ *  atest FrameworksCoreTests:android.view.stylus.HandwritingAreaTrackerTest
+ */
+@Presubmit
+@SmallTest
+@RunWith(AndroidJUnit4.class)
+public class HandwritingAreaTrackerTest {
+    HandwritingInitiator.HandwritingAreaTracker mHandwritingAreaTracker;
+    Context mContext;
+
+    @Before
+    public void setup() {
+        final Instrumentation mInstrumentation = InstrumentationRegistry.getInstrumentation();
+        mContext = mInstrumentation.getTargetContext();
+        mHandwritingAreaTracker = new HandwritingInitiator.HandwritingAreaTracker();
+    }
+
+    @Test
+    public void updateHandwritingAreaForView_singleView() {
+        Rect rect = new Rect(0, 0, 100, 100);
+        View view = createView(rect);
+        mHandwritingAreaTracker.updateHandwritingAreaForView(view);
+
+        List<HandwritingInitiator.HandwritableViewInfo> viewInfos =
+                mHandwritingAreaTracker.computeViewInfos();
+
+        assertThat(viewInfos.size()).isEqualTo(1);
+        assertThat(viewInfos.get(0).getHandwritingArea()).isEqualTo(rect);
+        assertThat(viewInfos.get(0).getView()).isEqualTo(view);
+    }
+
+    @Test
+    public void updateHandwritingAreaForView_multipleViews() {
+        Rect rect1 = new Rect(0, 0, 100, 100);
+        Rect rect2 = new Rect(100, 100, 200, 200);
+
+        View view1 = createView(rect1);
+        View view2 = createView(rect2);
+        mHandwritingAreaTracker.updateHandwritingAreaForView(view1);
+        mHandwritingAreaTracker.updateHandwritingAreaForView(view2);
+
+        List<HandwritingInitiator.HandwritableViewInfo> viewInfos =
+                mHandwritingAreaTracker.computeViewInfos();
+
+        assertThat(viewInfos.size()).isEqualTo(2);
+        assertThat(viewInfos.get(0).getView()).isEqualTo(view1);
+        assertThat(viewInfos.get(0).getHandwritingArea()).isEqualTo(rect1);
+
+        assertThat(viewInfos.get(1).getView()).isEqualTo(view2);
+        assertThat(viewInfos.get(1).getHandwritingArea()).isEqualTo(rect2);
+    }
+
+    @Test
+    public void updateHandwritingAreaForView_afterDisableAutoHandwriting() {
+        Rect rect1 = new Rect(0, 0, 100, 100);
+        Rect rect2 = new Rect(100, 100, 200, 200);
+
+        View view1 = createView(rect1);
+        View view2 = createView(rect2);
+        mHandwritingAreaTracker.updateHandwritingAreaForView(view1);
+        mHandwritingAreaTracker.updateHandwritingAreaForView(view2);
+
+        // There should be 2 views tracked.
+        assertThat(mHandwritingAreaTracker.computeViewInfos().size()).isEqualTo(2);
+
+        // Disable autoHandwriting for view1 and update handwriting area.
+        view1.setAutoHandwritingEnabled(false);
+        mHandwritingAreaTracker.updateHandwritingAreaForView(view1);
+
+        List<HandwritingInitiator.HandwritableViewInfo> viewInfos =
+                mHandwritingAreaTracker.computeViewInfos();
+        // The view1 has disabled the autoHandwriting, it's not tracked anymore.
+        assertThat(viewInfos.size()).isEqualTo(1);
+
+        // view2 is still tracked.
+        assertThat(viewInfos.get(0).getView()).isEqualTo(view2);
+        assertThat(viewInfos.get(0).getHandwritingArea()).isEqualTo(rect2);
+    }
+
+    @Test
+    public void updateHandwritingAreaForView_removesInactiveView() {
+        Rect rect1 = new Rect(0, 0, 100, 100);
+        Rect rect2 = new Rect(100, 100, 200, 200);
+
+        View view1 = createView(rect1);
+        View view2 = createView(rect2);
+        mHandwritingAreaTracker.updateHandwritingAreaForView(view1);
+        mHandwritingAreaTracker.updateHandwritingAreaForView(view2);
+
+        // There should be 2 viewInfos tracked.
+        assertThat(mHandwritingAreaTracker.computeViewInfos().size()).isEqualTo(2);
+
+        // Disable autoHandwriting for view1, but update handwriting area for view2.
+        view1.setAutoHandwritingEnabled(false);
+        mHandwritingAreaTracker.updateHandwritingAreaForView(view2);
+
+        List<HandwritingInitiator.HandwritableViewInfo> viewInfos =
+                mHandwritingAreaTracker.computeViewInfos();
+        // The view1 has disabled the autoHandwriting, it's not tracked anymore.
+        assertThat(viewInfos.size()).isEqualTo(1);
+
+        // view2 is still tracked.
+        assertThat(viewInfos.get(0).getView()).isEqualTo(view2);
+        assertThat(viewInfos.get(0).getHandwritingArea()).isEqualTo(rect2);
+    }
+}

core/tests/coretests/src/android/view/stylus/HandwritingInitiatorTest.java

@@ -19,6 +19,7 @@ package android.view.stylus;
 import static android.view.MotionEvent.ACTION_DOWN;
 import static android.view.MotionEvent.ACTION_MOVE;
 import static android.view.MotionEvent.ACTION_UP;
+import static android.view.stylus.HandwritingTestUtil.createView;
 
 import static com.google.common.truth.Truth.assertThat;
 
@@ -38,7 +39,6 @@ import android.view.InputDevice;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewConfiguration;
-import android.view.ViewGroup;
 import android.view.inputmethod.InputMethodManager;
 
 import androidx.test.ext.junit.runners.AndroidJUnit4;
@@ -78,7 +78,8 @@ public class HandwritingInitiatorTest {
         mHandwritingInitiator =
                 spy(new HandwritingInitiator(viewConfiguration, inputMethodManager));
 
-        mTestView = createMockView(sHwArea, true);
+        mTestView = createView(sHwArea, true);
+        mHandwritingInitiator.updateHandwritingAreasForView(mTestView);
     }
 
     @Test
@@ -194,9 +195,26 @@ public class HandwritingInitiatorTest {
         verify(mHandwritingInitiator, never()).startHandwriting(mTestView);
     }
 
+    @Test
+    public void onTouchEvent_focusView_stylusMoveOnce_withinHWArea() {
+        final int x1 = (sHwArea.left + sHwArea.right) / 2;
+        final int y1 = (sHwArea.top + sHwArea.bottom) / 2;
+        MotionEvent stylusEvent1 = createStylusEvent(ACTION_DOWN, x1, y1, 0);
+        mHandwritingInitiator.onTouchEvent(stylusEvent1);
+
+        final int x2 = x1 + TOUCH_SLOP * 2;
+        final int y2 = y1;
+
+        MotionEvent stylusEvent2 = createStylusEvent(ACTION_MOVE, x2, y2, 0);
+        mHandwritingInitiator.onTouchEvent(stylusEvent2);
+
+        // HandwritingInitiator will request focus for the registered view.
+        verify(mTestView, times(1)).requestFocus();
+    }
+
     @Test
     public void autoHandwriting_whenDisabled_wontStartHW() {
-        View mockView = createMockView(sHwArea, false);
+        View mockView = createView(sHwArea, false);
         mHandwritingInitiator.onInputConnectionCreated(mockView);
         final int x1 = (sHwArea.left + sHwArea.right) / 2;
         final int y1 = (sHwArea.top + sHwArea.bottom) / 2;
@@ -273,25 +291,4 @@ public class HandwritingInitiatorTest {
                 1 /* yPrecision */, 0 /* deviceId */, 0 /* edgeFlags */,
                 InputDevice.SOURCE_TOUCHSCREEN, 0 /* flags */);
     }
-
-    private View createMockView(Rect viewBound, boolean autoHandwritingEnabled) {
-        // mock a parent so that HandwritingInitiator can get
-        ViewGroup parent = new ViewGroup(mContext) {
-            @Override
-            protected void onLayout(boolean changed, int l, int t, int r, int b) {
-                // We don't layout this view.
-            }
-            @Override
-            public boolean getChildVisibleRect(View child, Rect r, android.graphics.Point offset) {
-                r.set(viewBound);
-                return true;
-            }
-        };
-
-        View mockView = mock(View.class);
-        when(mockView.isAttachedToWindow()).thenReturn(true);
-        when(mockView.isAutoHandwritingEnabled()).thenReturn(autoHandwritingEnabled);
-        parent.addView(mockView);
-        return mockView;
-    }
 }

core/tests/coretests/src/android/view/stylus/HandwritingTestUtil.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2022 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 android.view.stylus;
+
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.when;
+
+import android.app.Instrumentation;
+import android.content.Context;
+import android.graphics.Rect;
+import android.view.View;
+import android.view.ViewGroup;
+
+import androidx.test.platform.app.InstrumentationRegistry;
+
+public class HandwritingTestUtil {
+    public static View createView(Rect handwritingArea) {
+        return createView(handwritingArea, true);
+    }
+
+    public static View createView(Rect handwritingArea, boolean autoHandwritingEnabled) {
+        final Instrumentation instrumentation = InstrumentationRegistry.getInstrumentation();
+        final Context context = instrumentation.getTargetContext();
+        // mock a parent so that HandwritingInitiator can get
+        final ViewGroup parent = new ViewGroup(context) {
+            @Override
+            protected void onLayout(boolean changed, int l, int t, int r, int b) {
+                // We don't layout this view.
+            }
+            @Override
+            public boolean getChildVisibleRect(View child, Rect r, android.graphics.Point offset) {
+                r.set(handwritingArea);
+                return true;
+            }
+        };
+
+        View view = spy(new View(context));
+        when(view.isAttachedToWindow()).thenReturn(true);
+        when(view.isAggregatedVisible()).thenReturn(true);
+        when(view.getHandwritingArea()).thenReturn(handwritingArea);
+        view.setAutoHandwritingEnabled(autoHandwritingEnabled);
+        parent.addView(view);
+        return view;
+    }
+}