Handler使用

一、前言：

Handler是android为我们封装的一套消息处理的机制，也是一套子线程用来更新UI的机制

1、Java使用：

public class MainActivity extends AppCompatActivity {

    private Handler mHandler = new Handler();
    private MyRunnable mr = new MyRunnable();
    private int index = 0;

    class MyRunnable implements Runnable {
        public void run() {
            index++;
            Log.d("8888","====index: "+index);
            mHandler.postDelayed(mr, 1000);
        }
    }

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mHandler.postDelayed(mr, 1000);
    }
}

//移除handler
mHandler.removeCallbacks(mr )

2、Kotlin使用：

   var handler: Handler = Handler()
    //执行
    handler.postDelayed(this, 100)

    var runnable: Runnable = object : Runnable {
    override fun run() {
        //操作事件 
        .........
       //延迟1秒
       handler.postDelayed(this, 1000)
      }
  }

//移除handler
handler.removeCallbacks(runnable)