Merge branch 'flutter_1.5_upgrade_opt' of...

Merge branch 'flutter_1.5_upgrade_opt' of https://github.com/alibaba/flutter_boost into flutter_1.5_upgrade_opt

android/src/main/java/com/idlefish/flutterboost/FlutterViewContainerManager.java

@@ -121,8 +121,9 @@ public class FlutterViewContainerManager implements IContainerManager {
         }
 
         int requestCode = 0;
-        if (urlParams.containsKey("requestCode")) {
-            requestCode = Integer.valueOf((String)urlParams.remove("requestCode"));
+        final Object v = urlParams.remove("requestCode");
+        if(v != null) {
+            requestCode = Integer.valueOf(String.valueOf(v));
         }
 
         final String uniqueId = ContainerRecord.genUniqueId(url);