android的HandlerMessage机制*

Posted 2021-07-03 月疯

handler的写法： 

private Handler mHandler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            switch (msg.what){
                case 0:
                
                    break;

                case 1:
                    String json = (String) msg.obj;
                    content.setText(json);
                   
                    break;
            }
        }
    };

message的写法：

class MyThread extends Thread {
        @Override
        public void run() {
            isDownloading = true;
            Log.d(TAG,"MyThread start run");
            //发送消息给mHander
            mHandler.sendEmptyMessage(MSG_DOWN_START);
            try { //让线程睡眠3s。
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            Message msg = new Message();
            msg.what = MSG_DOWN_SUCCESS;
            //msg.arg1 = 111;  可以设置arg1、arg2、obj等参数，传递这些数据
            //msg.arg2 = 222; msg.obj = obj;
            mHandler.sendMessage(msg);
            isDownloading = false;
            Log.d(TAG,"MyThread stop run");
        }
    }

这就是简单的演示过程。