Android app主線程UI更新間歇性崩潰的問題

　　對App進行開發測試時，偶爾出現app崩潰的問題。日誌以下：

10-25 18:44:52.935  15290-15290/com.zzq.cnblogs E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.zzq.cnblogs, PID: 15290
    java.lang.IllegalStateException: The content of the adapter has changed but ListView did not receive a notification. Make sure the content of your adapter is not modified from a background thread, but only from the UI thread. Make sure your adapter calls notifyDataSetChanged() when its content changes. [in ListView(16908298, class com.handmark.pulltorefresh.library.PullToRefreshListView$InternalListViewSDK9) with Adapter(class android.widget.HeaderViewListAdapter)]
            at android.widget.ListView.layoutChildren(ListView.java:1555)
            at android.widget.AbsListView.onLayout(AbsListView.java:2089)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
            at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
            at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
            at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
            at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
            at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1055)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
            at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:1043)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
            at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.support.v7.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:437)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
            at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
            at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
            at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
            at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
            at android.view.View.layout(View.java:14845)
            at android.view.ViewGroup.layout(ViewGroup.java:4631)
            at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2026)
            at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1783)
            at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1039)
            at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5648)
            at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
            at android.view.Choreographer.doCallbacks(Choreographer.java:574)
            at android.view.Choreographer.doFrame(Choreographer.java:544)
            at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.j

　　其中

The content of the adapter has changed but ListView did not receive a notification. Make sure the content of your adapter is not modified from a background thread, but only from the UI thread.

　　由異常的提示能夠看出，在一個後臺線程更新了UI界面，而UI界面必須由UI線程進行更新。然而，Android提供了幾種更新UI線程的方法。下面用Handler的方式更新UI，作個簡單的修改便可。更多關於UI線程更新的方法見：http://gqdy365.iteye.com/blog/2112471

　　一、添加一個Handler屬性

    private Handler handlerListView = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            Bundle bundle = (Bundle) msg.obj;
            int refreshType = (int) bundle.get("refreshType");
            LinkedList<Article> list = (LinkedList<Article>) bundle.get("article");
            for (Article article : list){
                if (REFRESH_TYPE_UP == refreshType){
                    listData.add(article);
                }else if (REFRESH_TYPE_DOWN == refreshType){
                    listData.add(0, article);
                }
            }

            pullToRefreshView.onRefreshComplete();
            adapter.notifyDataSetChanged();
        }
    };

　　二、將直接更新UI內容的部分

　　pullToRefreshView.onRefreshComplete();
　　adapter.notifyDataSetChanged();

　　改爲

    Message msg = new Message();
    Bundle bundle = new Bundle();
    bundle.putInt("refreshType", refreshType);
    bundle.putSerializable("article", addList);
    msg.obj = bundle;
    handlerListView.sendMessage(msg);

　　將修改的數據發給handler去處理，而不是直接操做listview的adapter。

　　此外還能夠考慮使用activity的runOnUiThread方法進行更新。