public class MainActivity extends AppCompatActivity {

    private TextView textView;
    private String TAG = "MainActivity";
    private int i = 0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textView = (TextView) findViewById(R.id.textView);
    }
    public void onClick(View v){
        ++i;
        //建立新的執行緒
        new Thread(){
            @Override
            public void run() {
                super.run();
                doSendMsg();
            }
        }.start();
    }

    /*
     * 在子執行緒中做耗時操作，完成之後，通知Handler更新UI
     */
    private void doSendMsg(){
        try {
            Thread.sleep(1000);//模擬耗時操作
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        Message message = Message.obtain();
        message.arg1 = i;
        message.what = 1;
        mHandler.sendMessage(message);
    }

    Handler mHandler = new Handler(){
        /*
         * handleMessage接收訊息後進行相應的處理
         */
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            if(msg.what==1){
                textView.setText(msg.arg1+"");
            }
        }
    };
}