The application may be doing too much work on its main thread.

最近學習handler中的回調：handler.callback。出現異常

I/Choreographer: Skipped 179 frames!  The application may be doing too much work on its main thread.

意思是：主線程中有耗時操作，主線程受不了了。原因是我在重寫callback的handleMessage方法時，模擬了延時操作。實際在開發中，這種情況是萬萬不可的，解決辦法是實現android的兩大原則：

1. 不要！不要在主線程（UI線程）中執行耗時操作，如網絡請求，數據庫操作等。應另開線程操作，實現方式有1) 自開線程new Thread；2) runOnUIThread; 3) post方法以及4) 異步AsyncTask

2. 一定！一定要在主線程（UI線程）中修改控件的狀態。否則會報：Only the original thread that created a view hierarchy can touch its views

 

這里順便給出handler的回調機制實現

代碼實現：

1. 實例化消息message

        // declare a message
        Message message = new Message();
        message.obj = "Don't call me, I'll call you";

2. 實例化Handler.Callback，重寫handleMessage方法

        // declare a callback obj
        Handler.Callback callback = new Handler.Callback() {
            @Override
            public boolean handleMessage(Message msg) {
                // make a pause
                SystemClock.sleep(3_000); // 就是這里出了問題，這是個耗時操作，應扔到另一個線程中

                // <code to be executed during callback>
                Log.d("TOM", "Don't call me, I'll call you");
                return true;
            }
        };    

3. 發送消息

        // send message
        new Handler(callback).sendMessage(message);

參考鏈接：

http://stackoverflow.com/questions/14678593/the-application-may-be-doing-too-much-work-on-its-main-thread