Android之Handler消息处理

主要用途

• 未来某时做某事
• 线程间通信

package com.example.test0508;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;

import com.example.test0508.util.ToastUtil;

public class HandlerActivity extends AppCompatActivity {

    private Handler mHandler;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_handler);
        


        //直观的线程通信
        mHandler = new Handler(){
            @Override
            public void handleMessage(Message msg) {
                super.handleMessage(msg);
                switch (msg.what){
                    case 1:
                        ToastUtil.showMessage(HandlerActivity.this,"线程通信成功");
                        break;
                }
            }
        };
        //延时五秒后跳转到另一个activity
        mHandler.postDelayed(new Runnable() {
            @Override
            public void run() {
                Intent intent = new Intent(HandlerActivity.this,EventActivity.class);
                startActivity(intent);
            }
        }, 5000);

        new Thread(){
            @Override
            public void run() {
                super.run();
                Message message = new Message();
                message.what = 1;
                mHandler.sendMessage(message);
            }
        }.start();
    }
}

布局文件随便写