Handler用法

handler ：更新UI的機制，消息的處理機制

四種用法sendMessage、sendMessageDelayed、post(runnable)、postDelayed(Runnable,long)

 

post用法

    private android.os.Handler handler = new android.os.Handler();

    new Thread() {
            public void run() {
                try {
                    Thread.sleep(1000);
                    handler.post(new Runnable() {
                        @Override
                        public void run() {
                            text.setText("123");
                        }
                    });
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }.start();

 

sendMessage用法

    private android.os.Handler handler = new android.os.Handler() {
        @Override
        public void handleMessage(Message msg) {
            text.setText("" + msg.arg1);
        }
    };

   new Thread() {
            @Override
            public void run() {
                try {
                    Thread.sleep(1000);
                    Message message = new Message();
                    message.arg1 = 100;
　　　　　　　　　　　　//handler.sendMessage(XXX);對象能夠是int，也能夠是obj對象
　　　　　　　　　　　　//message.obj=Person; Person是一個實體類對象
                    handler.sendMessage(message);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }.start();    

 

加上一個本身寫的頁面自動滑動的demo , 不是最正確的，只是能夠用的。

    private Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case 1:
                    textView.setText("11111");
                    break;
                case 2:
                    textView.setText("22222");
                    break;
                default:
                    textView.setText("33333");
                    break;
            }
        }
    };

 

        button1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                new Thread() {
                    @Override
                    public void run() {
                        for (int i = 1; i < 10000; i++) {
                            try {
                                Message message = new Message();
                                message.what = i % 3;
                                handler.sendMessageDelayed(message, 1000);
                                sleep(1000);
                            } catch (Exception e) {
                                e.printStackTrace();
                            }
                        }
                    }
                }.start();
            }
        });