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package net.zjs.xianxing;import androidx.appcompat.app.AppCompatActivity;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.view.View;import android.widget.TextView;import java.text.SimpleDateFormat;import java.util.Date;public class shuji extends AppCompatActivity { private Thread thread; private Handler handler; private TextView tvTime; private SimpleDateFormat sdf; private boolean anniu; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //利用布局资源文件设置用户界面 setContentView(R.layout.activity_shuji); //通过资源标识获得控件实例 tvTime = findViewById(R.id.tv_time); //实例化简单日期格式化对象 sdf = new SimpleDateFormat("hh:mm:ss"); tvTime.setText(sdf.format(new Date())); //创建消息处理器,送的消息进行处理,更新主界面元素(标签)的内容 handler = new Handler(){ public void handleMessage(Message msg){ super.handleMessage(msg); if(msg.what ==0x0001){ tvTime.setText(sdf.format(new Date())); } } }; //创建线程,定时发送消息 } public void doStart(View view){ anniu =true; thread = new Thread(new Runnable() { @Override public void run() { while(anniu){ //向主线程发送消息 handler.sendEmptyMessage(0x001); //让线程睡眠500毫秒 try { Thread.sleep(500); }catch (InterruptedException e){ e.printStackTrace(); } } } }); //启动线程 thread.start(); } public void doStop(View view){ anniu = false; thread =null; } protected void onDestroy(){ super.onDestroy(); //销毁线程 thread = null; }}
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