[android] - move camera logic to dedicated transform class (#6919)

* [android] - move camera logic to dedicated transform class

post camera updates to the message queue, this makes calling an new camera update in the on finish of another update possible. Simplify transform.java implementation.

* fail the step if instrumentation tests fail, fixup typo

1 files changed, 143 insertions, 0 deletions

diff --git a/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/Transform.java b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/Transform.java
new file mode 100644
index 0000000000..1532bb6745
--- /dev/null
+++ b/platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/maps/Transform.java
@@ -0,0 +1,143 @@
+package com.mapbox.mapboxsdk.maps;
+
+import android.support.annotation.Nullable;
+import android.support.annotation.UiThread;
+
+import com.mapbox.mapboxsdk.camera.CameraPosition;
+import com.mapbox.mapboxsdk.camera.CameraUpdate;
+
+import java.util.concurrent.TimeUnit;
+
+import static com.mapbox.mapboxsdk.maps.MapView.REGION_DID_CHANGE_ANIMATED;
+
+/**
+ * Resembles the current Map transformation.
+ * <p>
+ * Responsible for synchronising {@link CameraPosition} state and notifying {@link com.mapbox.mapboxsdk.maps.MapboxMap.OnCameraChangeListener}.
+ * </p>
+ */
+class Transform {
+
+    private NativeMapView mapView;
+    private MapboxMap mapboxMap;
+
+    private CameraPosition cameraPosition;
+    private MapboxMap.CancelableCallback cameraCancelableCallback;
+    private MapboxMap.OnCameraChangeListener onCameraChangeListener;
+
+    Transform(NativeMapView mapView, MapboxMap mapboxMap) {
+        this.mapView = mapView;
+        this.mapboxMap = mapboxMap;
+    }
+
+    //
+    // Camera API
+    //
+
+    @UiThread
+    public final CameraPosition getCameraPosition() {
+        if (cameraPosition == null) {
+            cameraPosition = invalidateCameraPosition();
+        }
+        return cameraPosition;
+    }
+
+    @UiThread
+    final void moveCamera(CameraUpdate update, MapboxMap.CancelableCallback callback) {
+        cameraPosition = update.getCameraPosition(mapboxMap);
+        mapboxMap.getTrackingSettings().resetTrackingModesIfRequired(cameraPosition);
+        cancelTransitions();
+        mapView.jumpTo(cameraPosition.bearing, cameraPosition.target, cameraPosition.tilt, cameraPosition.zoom);
+
+        // MapChange.REGION_DID_CHANGE_ANIMATED is not called for `jumpTo`
+        // invalidate camera position to provide OnCameraChange event.
+        mapboxMap.invalidateCameraPosition();
+        if (callback != null) {
+            callback.onFinish();
+        }
+    }
+
+    @UiThread
+    final void easeCamera(CameraUpdate update, int durationMs, boolean easingInterpolator, boolean resetTrackingMode, final MapboxMap.CancelableCallback callback) {
+        cameraPosition = update.getCameraPosition(mapboxMap);
+        if (resetTrackingMode) {
+            mapboxMap.getTrackingSettings().resetTrackingModesIfRequired(cameraPosition);
+        }
+
+        cancelTransitions();
+        if (callback != null) {
+            cameraCancelableCallback = callback;
+            mapView.addOnMapChangedListener(new MapView.OnMapChangedListener() {
+                @Override
+                public void onMapChanged(@MapView.MapChange int change) {
+                    if (change == REGION_DID_CHANGE_ANIMATED && cameraCancelableCallback != null) {
+                        cameraCancelableCallback.onFinish();
+                        cameraCancelableCallback = null;
+                        mapView.removeOnMapChangedListener(this);
+                    }
+                }
+            });
+        }
+
+        mapView.easeTo(cameraPosition.bearing, cameraPosition.target, getDurationNano(durationMs), cameraPosition.tilt, cameraPosition.zoom, easingInterpolator);
+    }
+
+    @UiThread
+    final void animateCamera(CameraUpdate update, int durationMs, final MapboxMap.CancelableCallback callback) {
+        cameraPosition = update.getCameraPosition(mapboxMap);
+        mapboxMap.getTrackingSettings().resetTrackingModesIfRequired(cameraPosition);
+
+        cancelTransitions();
+        if (callback != null) {
+            cameraCancelableCallback = callback;
+            mapView.addOnMapChangedListener(new MapView.OnMapChangedListener() {
+                @Override
+                public void onMapChanged(@MapView.MapChange int change) {
+                    if (change == REGION_DID_CHANGE_ANIMATED && cameraCancelableCallback != null) {
+                        cameraCancelableCallback.onFinish();
+                        cameraCancelableCallback = null;
+                        mapView.removeOnMapChangedListener(this);
+                    }
+                }
+            });
+        }
+
+        mapView.flyTo(cameraPosition.bearing, cameraPosition.target, getDurationNano(durationMs), cameraPosition.tilt, cameraPosition.zoom);
+    }
+
+    @UiThread
+    @Nullable
+    CameraPosition invalidateCameraPosition() {
+        CameraPosition cameraPosition = null;
+        if (mapView != null) {
+            cameraPosition = new CameraPosition.Builder(mapView.getCameraValues()).build();
+            this.cameraPosition = cameraPosition;
+            if (onCameraChangeListener != null) {
+                onCameraChangeListener.onCameraChange(this.cameraPosition);
+            }
+        }
+        return cameraPosition;
+    }
+
+    void cancelTransitions() {
+        if (cameraCancelableCallback != null) {
+            cameraCancelableCallback.onCancel();
+            cameraCancelableCallback = null;
+        }
+        mapView.cancelTransitions();
+    }
+
+    @UiThread
+    void resetNorth() {
+        cancelTransitions();
+        mapView.resetNorth();
+    }
+
+    void setOnCameraChangeListener(@Nullable MapboxMap.OnCameraChangeListener listener) {
+        this.onCameraChangeListener = listener;
+    }
+
+    private long getDurationNano(long durationMs) {
+        return durationMs > 0 ? TimeUnit.NANOSECONDS.convert(durationMs, TimeUnit.MILLISECONDS) : 0;
+    }
+}