[android] ensure that move detector is enabled if double-tap is interrupted

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapGestureDetector.java

@@ -86,6 +86,8 @@ final class MapGestureDetector {
   @NonNull
   private Handler animationsTimeoutHandler = new Handler();
 
+  private boolean doubleTapRegistered;
+
   MapGestureDetector(@Nullable Context context, Transform transform, Projection projection, UiSettings uiSettings,
                      AnnotationManager annotationManager, CameraChangeDispatcher cameraChangeDispatcher) {
     this.annotationManager = annotationManager;
@@ -199,7 +201,12 @@ final class MapGestureDetector {
     boolean result = gesturesManager.onTouchEvent(motionEvent);
 
     switch (motionEvent.getActionMasked()) {
+      case MotionEvent.ACTION_POINTER_DOWN:
+        doubleTapFinished();
+        break;
+
       case MotionEvent.ACTION_UP:
+        doubleTapFinished();
         transform.setGestureInProgress(false);
 
         if (!scheduledAnimators.isEmpty()) {
@@ -215,6 +222,7 @@ final class MapGestureDetector {
       case MotionEvent.ACTION_CANCEL:
         scheduledAnimators.clear();
         transform.setGestureInProgress(false);
+        doubleTapFinished();
         break;
     }
 
@@ -344,16 +352,10 @@ final class MapGestureDetector {
       int action = motionEvent.getActionMasked();
       if (action == MotionEvent.ACTION_DOWN) {
         doubleTapFocalPoint = new PointF(motionEvent.getX(), motionEvent.getY());
-
-        // disable the move detector in preparation for the quickzoom,
-        // so that we don't move the map's center slightly before the quickzoom is started (see #14227)
-        gesturesManager.getMoveGestureDetector().setEnabled(false);
+        doubleTapStarted();
       }
 
       if (motionEvent.getActionMasked() == MotionEvent.ACTION_UP) {
-        // re-enable the move detector
-        gesturesManager.getMoveGestureDetector().setEnabled(true);
-
         float diffX = Math.abs(motionEvent.getX() - doubleTapFocalPoint.x);
         float diffY = Math.abs(motionEvent.getY() - doubleTapFocalPoint.y);
         if (diffX > doubleTapMovementThreshold || diffY > doubleTapMovementThreshold) {
@@ -426,6 +428,21 @@ final class MapGestureDetector {
     }
   }
 
+  private void doubleTapStarted() {
+    // disable the move detector in preparation for the quickzoom,
+    // so that we don't move the map's center slightly before the quickzoom is started (see #14227)
+    gesturesManager.getMoveGestureDetector().setEnabled(false);
+    doubleTapRegistered = true;
+  }
+
+  private void doubleTapFinished() {
+    if (doubleTapRegistered) {
+      // re-enable the move detector in case of double tap
+      gesturesManager.getMoveGestureDetector().setEnabled(true);
+      doubleTapRegistered = false;
+    }
+  }
+
   private final class MoveGestureListener extends MoveGestureDetector.SimpleOnMoveGestureListener {
     @Override
     public boolean onMoveBegin(@NonNull MoveGestureDetector detector) {
@@ -481,6 +498,8 @@ final class MapGestureDetector {
         if (!uiSettings.isQuickZoomGesturesEnabled()) {
           return false;
         }
+        // re-try disabling the move detector in case double tap has been interrupted before quickzoom started
+        gesturesManager.getMoveGestureDetector().setEnabled(false);
       }
 
       cancelTransitionsIfRequired();
@@ -516,9 +535,7 @@ final class MapGestureDetector {
     @Override
     public void onScaleEnd(@NonNull StandardScaleGestureDetector detector, float velocityX, float velocityY) {
       if (quickZoom) {
-        // re-enabled the move detector only if the quickzoom happened
-        // we need to split the responsibility of re-enabling the move detector,
-        // because the double tap event (where the detector is disabled) can be canceled without warning (see #14598)
+        // re-enabled the move detector if the quickzoom happened
         gesturesManager.getMoveGestureDetector().setEnabled(true);
       }
 

platform/android/MapboxGLAndroidSDKTestApp/src/androidTest/java/com/mapbox/mapboxsdk/maps/MapGestureDetectorTest.kt

@@ -158,4 +158,29 @@ class MapGestureDetectorTest : BaseTest() {
       Assert.assertEquals(initialZoom!!, mapboxMap.cameraPosition.zoom, 0.01)
     }
   }
+
+  @Test
+  fun doubleTap_interrupted_moveStillEnabled() {
+    validateTestSetup()
+
+    rule.runOnUiThread {
+      mapboxMap.moveCamera(CameraUpdateFactory.zoomTo(4.0))
+    }
+
+    onView(withId(R.id.mapView)).perform(quickScale(mapboxMap.gesturesManager.standardScaleGestureDetector.spanSinceStartThreshold / 2, withVelocity = false, duration = 50L, interrupt = true))
+
+    var expectedTarget: LatLng? = null
+    rule.runOnUiThread {
+      val currentPoint = mapboxMap.projection.toScreenLocation(mapboxMap.cameraPosition.target)
+      val resultingPoint = PointF(currentPoint.x + maxWidth / 2f, currentPoint.y + maxHeight / 2f)
+      expectedTarget = mapboxMap.projection.fromScreenLocation(resultingPoint)
+    }
+
+    // move to expected target
+    onView(withId(R.id.mapView)).perform(move(-maxWidth / 2f, -maxHeight / 2f, withVelocity = false))
+    rule.runOnUiThread {
+      Assert.assertEquals(expectedTarget!!.latitude, mapboxMap.cameraPosition.target.latitude, 10.0)
+      Assert.assertEquals(expectedTarget!!.longitude, mapboxMap.cameraPosition.target.longitude, 10.0)
+    }
+  }
 }