Support LTR/RTL layout directions for embedded Android views. (#6057)

shell/platform/android/io/flutter/plugin/platform/PlatformViewsController.java

@@ -96,17 +96,30 @@ public class PlatformViewsController implements MethodChannel.MethodCallHandler
             case "touch":
                 onTouch(call, result);
                 return;
+            case "setDirection":
+                setDirection(call, result);
+                return;
         }
         result.notImplemented();
     }
 
-    @TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1)
+    @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
     private void createPlatformView(MethodCall call, MethodChannel.Result result) {
         Map<String, Object> args = call.arguments();
         int id = (int) args.get("id");
         String viewType = (String) args.get("viewType");
         double logicalWidth = (double) args.get("width");
         double logicalHeight = (double) args.get("height");
+        int direction = (int) args.get("direction");
+
+        if (!validateDirection(direction)) {
+            result.error(
+                    "error",
+                    "Trying to create a view with unknown direction value: " + direction + "(view id: " + id + ")",
+                    null
+            );
+            return;
+        }
 
         if (vdControllers.containsKey(id)) {
             result.error(
@@ -147,6 +160,7 @@ public class PlatformViewsController implements MethodChannel.MethodCallHandler
         }
 
         vdControllers.put(id, vdController);
+        vdController.getView().setLayoutDirection(direction);
 
         // TODO(amirh): copy accessibility nodes to the FlutterView's accessibility tree.
 
@@ -253,6 +267,39 @@ public class PlatformViewsController implements MethodChannel.MethodCallHandler
         result.success(null);
     }
 
+    @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
+    private void setDirection(MethodCall call, MethodChannel.Result result) {
+        Map<String, Object> args = call.arguments();
+        int id = (int) args.get("id");
+        int direction = (int) args.get("direction");
+
+        if (!validateDirection(direction)) {
+            result.error(
+                    "error",
+                    "Trying to set unknown direction value: " + direction + "(view id: " + id + ")",
+                    null
+            );
+            return;
+        }
+
+        View view = vdControllers.get(id).getView();
+        if (view == null) {
+            result.error(
+                    "error",
+                    "Sending touch to an unknown view with id: " + id,
+                    null
+            );
+            return;
+        }
+
+        view.setLayoutDirection(direction);
+        result.success(null);
+    }
+
+    private static boolean validateDirection(int direction) {
+        return direction == View.LAYOUT_DIRECTION_LTR || direction == View.LAYOUT_DIRECTION_RTL;
+    }
+
     @SuppressWarnings("unchecked")
     private static List<PointerProperties> parsePointerPropertiesList(Object rawPropertiesList) {
         List<Object> rawProperties = (List<Object>) rawPropertiesList;