1：服务端使用PHP

复制代码 代码如下:
<?php
echo date('Y-m-d H:i:s');
?>

2：activity_main.xml

复制代码 代码如下:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">

<Button
android:id="@+id/btn_click"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button Start"/>

<TextView
android:id="@+id/tv_show"
android:layout_below="@id/btn_click"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world"
android:textSize="28sp"/>

<Button
android:id="@+id/btn_stop"
android:layout_below="@id/tv_show"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button Stop"/>

</RelativeLayout>

3:MainActivity.java

HttpHelper.getStringFromNet2(param)此方法见：

复制代码 代码如下:
public class MainActivity extends Activity {
private Button btnClick=null;
private Button btnStop=null;
private TextView tvShow=null;
private String info="";
private Timer timer=null;

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

btnClick=(Button)findViewById(R.id.btn_click);
btnStop=(Button)findViewById(R.id.btn_stop);
tvShow=(TextView)findViewById(R.id.tv_show);

timer=new Timer();

btnClick.setOnClickListener(new OnClickListener(){
public void onClick(View view){
timer.scheduleAtFixedRate(new MyTask(), 100, 2000);
}
});

btnStop.setOnClickListener(new OnClickListener(){
public void onClick(View view){
timer.cancel();
}
});

}

Handler myHandler=new Handler(){
public void handleMessage(Message msg){
if(info!=""){
tvShow.setText(info);
}
}
};

private class MyTask extends TimerTask{
public void run(){
String param="http://192.168.0.116/android/time.php";
info=HttpHelper.getStringFromNet2(param);
myHandler.obtainMessage(100).sendToTarget();
}
}
}

4:运行结果：