方法重复问题 # review by 孙凯

@@ -38,10 +38,6 @@ export default class Message extends Component {
         );
     }
 
-    componentWillUnmount() {
-        this.viewDidAppear && this.viewDidAppear.remove();
-    }
-
     trigggePullToRefresh() {
         if (Platform.OS === 'ios') {
             this.timer = TimerMixin.setTimeout(() => {
@@ -53,6 +49,7 @@ export default class Message extends Component {
     }
 
     componentWillUnmount() {
+        this.viewDidAppear && this.viewDidAppear.remove();
         this.timer && TimerMixin.clearTimeout(this.timer);
     }