package de.bvb.test;

import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import java.lang.ref.WeakReference;

public class MainActivity extends Activity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        new Thread(new Runnable() {

            @Override

            public void run() {

                //3.子线程中发送消息

                handler.sendEmptyMessage(1);

            }

        }).start();

    }

    @Override

    protected void onDestroy() {

        super.onDestroy();

        //4.在onDestroy把消息对象从消息队列移除

        handler.removeCallbacksAndMessages(null);

    }

    //2.创建handler的实例

    private Handler handler = new MyHandler(this);

    //1.创建静态的自定义Handler类

    static class MyHandler extends Handler {

        private WeakReference<Activity> mWeakReference;

        //传入activity,加上弱引用

        public MyHandler(Activity activity) {

            mWeakReference = new WeakReference<>(activity);

        }

        //在handleMessage处理业务

        @Override

        public void handleMessage(Message msg) {

            Activity activity = mWeakReference.get();

            if (activity != null) {

                switch (msg.what) {

                    case 1:

                        break;

                    default:

                        break;

                }

            }

        }

    }

}