Merge "Fix BaseSwipeDetector#setState() called inside another setState()" into ub-launcher3-master

src/com/android/launcher3/touch/AbstractStateChangeTouchController.java

@@ -508,7 +508,7 @@ public abstract class AbstractStateChangeTouchController
             mAtomicComponentsController.getAnimationPlayer().end();
             mAtomicComponentsController = null;
         }
-        cancelAnimationControllers();
+        clearState();
         boolean shouldGoToTargetState = true;
         if (mPendingAnimation != null) {
             boolean reachedTarget = mToState == targetState;
@@ -546,13 +546,13 @@ public abstract class AbstractStateChangeTouchController
             mAtomicAnim = null;
         }
         mScheduleResumeAtomicComponent = false;
+        mDetector.finishedScrolling();
+        mDetector.setDetectableScrollConditions(0, false);
     }
 
     private void cancelAnimationControllers() {
         mCurrentAnimation = null;
         cancelAtomicComponentsController();
-        mDetector.finishedScrolling();
-        mDetector.setDetectableScrollConditions(0, false);
     }
 
     private void cancelAtomicComponentsController() {

src/com/android/launcher3/touch/BaseSwipeDetector.java

@@ -24,6 +24,10 @@ import android.view.VelocityTracker;
 import android.view.ViewConfiguration;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.VisibleForTesting;
+
+import java.util.LinkedList;
+import java.util.Queue;
 
 /**
  * Scroll/drag/swipe gesture detector.
@@ -49,13 +53,15 @@ public abstract class BaseSwipeDetector {
     protected final boolean mIsRtl;
     protected final float mTouchSlop;
     protected final float mMaxVelocity;
+    private final Queue<Runnable> mSetStateQueue = new LinkedList<>();
 
     private int mActivePointerId = INVALID_POINTER_ID;
     private VelocityTracker mVelocityTracker;
     private PointF mLastDisplacement = new PointF();
     private PointF mDisplacement = new PointF();
     protected PointF mSubtractDisplacement = new PointF();
-    private ScrollState mState = ScrollState.IDLE;
+    @VisibleForTesting ScrollState mState = ScrollState.IDLE;
+    private boolean mIsSettingState;
 
     protected boolean mIgnoreSlopWhenSettling;
 
@@ -195,6 +201,12 @@ public abstract class BaseSwipeDetector {
     // SETTLING -> (View settled) -> IDLE
 
     private void setState(ScrollState newState) {
+        if (mIsSettingState) {
+            mSetStateQueue.add(() -> setState(newState));
+            return;
+        }
+        mIsSettingState = true;
+
         if (DBG) {
             Log.d(TAG, "setState:" + mState + "->" + newState);
         }
@@ -212,6 +224,10 @@ public abstract class BaseSwipeDetector {
         }
 
         mState = newState;
+        mIsSettingState = false;
+        if (!mSetStateQueue.isEmpty()) {
+            mSetStateQueue.remove().run();
+        }
     }
 
     private void initializeDragging() {

tests/src/com/android/launcher3/touch/SingleAxisSwipeDetectorTest.java

@@ -21,9 +21,11 @@ import static com.android.launcher3.touch.SingleAxisSwipeDetector.DIRECTION_POSI
 import static com.android.launcher3.touch.SingleAxisSwipeDetector.HORIZONTAL;
 import static com.android.launcher3.touch.SingleAxisSwipeDetector.VERTICAL;
 
+import static org.junit.Assert.assertTrue;
 import static org.mockito.Matchers.anyBoolean;
 import static org.mockito.Matchers.anyFloat;
 import static org.mockito.Matchers.anyObject;
+import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.verify;
@@ -168,4 +170,21 @@ public class SingleAxisSwipeDetectorTest {
         // TODO: actually calculate the following parameters and do exact value checks.
         verify(mMockListener).onDragEnd(anyFloat());
     }
+
+    @Test
+    public void testInterleavedSetState() {
+        doAnswer(invocationOnMock -> {
+            // Sets state to IDLE. (Normally onDragEnd() will have state SETTLING.)
+            mDetector.finishedScrolling();
+            return null;
+        }).when(mMockListener).onDragEnd(anyFloat());
+
+        mGenerator.put(0, 100, 100);
+        mGenerator.move(0, 100, 100 + mTouchSlop);
+        mGenerator.move(0, 100, 100 + mTouchSlop * 2);
+        mGenerator.lift(0);
+        verify(mMockListener).onDragEnd(anyFloat());
+        assertTrue("SwipeDetector should be IDLE but was " + mDetector.mState,
+                mDetector.isIdleState());
+    }
 }