[Android] Fix blank page when JS exception raised before batch end. (#…

…2254)

* issue: #2253

If more than two pages exist and mCurrentBatchInstanceId not matches new instanceId, we will post all stashed actions at once.
That will cause losing efficacy of batch action, but it is acceptable because it's not serious problem.

android/sdk/src/main/java/com/taobao/weex/ui/WXRenderManager.java

@@ -49,6 +49,7 @@ public class WXRenderManager {
 
   private volatile ConcurrentHashMap<String, RenderContextImpl> mRenderContext;
   private WXRenderHandler mWXRenderHandler;
+  private String mCurrentBatchInstanceId = null;
   private ArrayList<Map<String,Object>> mBatchActions = new ArrayList<>();
   private final int MAX_DROP_FRAME_NATIVE_BATCH = 2000;
   private final static  String sKeyAction = "Action";
@@ -123,18 +124,38 @@ public void removeRenderStatement(String instanceId) {
   }
 
   private void postAllStashedGraphicAction(final String instanceId,final BasicGraphicAction action) {
-      ArrayList<Map<String, Object>> tmpList = new ArrayList<>(mBatchActions);
+      final RenderContextImpl renderContext = mRenderContext.get(instanceId);
+
+      /// keep actions if renderContext still exist
+      ArrayList<Map<String, Object>> tmpList = null;
+      if (renderContext != null) {
+        tmpList = new ArrayList<>(mBatchActions);
+      }
+
+      // clear stashed actions
       this.mBatchActions.clear();
+      mCurrentBatchInstanceId = null;
+      nativeBatchTimes = 0;
+
+      // return if renderContext has been destroyed
+      if (renderContext == null) {
+        return;
+      }
+
+      /// post actions if renderContext still exist
       ArrayList<BasicGraphicAction> actions = new ArrayList<>(tmpList.size());
       for (int i = 0 ; i < tmpList.size(); i ++) {
           Map<String, Object> item = tmpList.get(i);
-          BasicGraphicAction tmpAction = (BasicGraphicAction)item.get(sKeyAction);
+          Object mustBeAction = item.get(sKeyAction);
+          if (!(mustBeAction instanceof BasicGraphicAction)) {
+            continue;
+          }
+          BasicGraphicAction tmpAction = (BasicGraphicAction)mustBeAction;
           if (tmpAction.mActionType == BasicGraphicAction.ActionTypeBatchBegin || tmpAction.mActionType == BasicGraphicAction.ActionTypeBatchEnd) {
-              continue;
+            continue;
           }
           actions.add(tmpAction);
       }
-      nativeBatchTimes = 0;
       postGraphicAction(instanceId, new GraphicActionBatchAction(action.getWXSDKIntance(),action.getRef(), actions));
   }
 
@@ -144,6 +165,17 @@ public void postGraphicAction(final String instanceId, final BasicGraphicAction
       return;
     }
 
+    // If more than two pages exist and mCurrentBatchInstanceId not matches new instanceId, we will post all stashed actions at once.
+    // That will cause losing efficacy of batch action, but it is acceptable because it's not serious problem.
+    if (mCurrentBatchInstanceId != null && instanceId != null && !mCurrentBatchInstanceId.equals(instanceId) && mBatchActions.size() > 0) {
+      Map<String, Object> lastItem = mBatchActions.get(mBatchActions.size() - 1);
+      Object mustBeAction = lastItem.get(sKeyAction);
+      if (mustBeAction instanceof BasicGraphicAction) {
+        BasicGraphicAction lastAction = (BasicGraphicAction)mustBeAction;
+        postAllStashedGraphicAction(mCurrentBatchInstanceId, lastAction);
+      }
+    }
+
     if (action.mActionType == BasicGraphicAction.ActionTypeBatchEnd) {
         postAllStashedGraphicAction(instanceId,action);
         return;
@@ -155,6 +187,7 @@ public void postGraphicAction(final String instanceId, final BasicGraphicAction
             HashMap<String, Object> item = new HashMap<>(1);
             item.put(sKeyAction, action);
             mBatchActions.add(item);
+            mCurrentBatchInstanceId = instanceId;
             return;
         }
     }