[android] - improve fling gesture by calculating animation time from …

…velocity, ignore small fling gestures. (#7676)
mapbox · Jan 17, 2017 · b008ec4 · b008ec4
1 parent c257cb6
commit b008ec4
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Showing 2 changed files with 26 additions and 5 deletions.
diff --git a/...roid/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/constants/MapboxConstants.java b/...roid/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/constants/MapboxConstants.java
@@ -8,7 +8,7 @@
  */
 public class MapboxConstants {
 
-    /**
+   /**
      * Default Locale for data processing (ex: String.toLowerCase(MAPBOX_LOCALE, "foo"))
      */
     public static final Locale MAPBOX_LOCALE = Locale.US;
@@ -141,4 +141,14 @@ public class MapboxConstants {
     public static final String MAPBOX_SHARED_PREFERENCE_KEY_TELEMETRY_ENABLED = "mapboxTelemetryEnabled";
     public static final String MAPBOX_SHARED_PREFERENCE_KEY_TELEMETRY_STAGING_URL = "mapboxTelemetryStagingUrl";
     public static final String MAPBOX_SHARED_PREFERENCE_KEY_TELEMETRY_STAGING_ACCESS_TOKEN = "mapboxTelemetryStagingAccessToken";
+
+    /**
+    * Animation time of a fling gesture
+    */
+    public static final long ANIMATION_DURATION_FLING_BASE = ANIMATION_DURATION_SHORT;
+
+    /**
+    * Velocity threshold for a fling gesture
+    */
+    public static final long VELOCITY_THRESHOLD_IGNORE_FLING = 1000;
 }
diff --git a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapView.java b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/MapView.java
@@ -1986,17 +1986,28 @@ public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float ve
                 return false;
             }
 
+            // calculate velocity vector for xy dimensions, independent from screen size
+            double velocityXY = Math.hypot(velocityX / screenDensity, velocityY / screenDensity);
+            if (velocityXY < MapboxConstants.VELOCITY_THRESHOLD_IGNORE_FLING) {
+                // ignore short flings, these can occur when other gestures just have finished executing
+                return false;
+            }
+
             resetTrackingModesIfRequired(true, false);
 
+            // tilt results in a bigger translation, limiting input for #5281
             double tilt = getTilt();
-            double limitFactor = 2 + ((tilt != 0) ? (tilt / 10) : 0);
-            double offsetX = velocityX / limitFactor / screenDensity;
-            double offsetY = velocityY / limitFactor / screenDensity;
+            double tiltFactor = 1 + ((tilt != 0) ? (tilt / 10) : 0); /* 1 -> 7 */
+            double offsetX = velocityX / tiltFactor / screenDensity;
+            double offsetY = velocityY / tiltFactor / screenDensity;
+
+            // calculate animation time
+            long animationTime = (long) (velocityXY / 7 / tiltFactor + MapboxConstants.ANIMATION_DURATION_FLING_BASE);
 
             // Cancel any animation
             cancelTransitions();
 
-            nativeMapView.moveBy(offsetX, offsetY, MapboxConstants.ANIMATION_DURATION_FLING);
+            nativeMapView.moveBy(offsetX, offsetY, animationTime);
 
             MapboxMap.OnFlingListener listener = mapboxMap.getOnFlingListener();
             if (listener != null) {