Handler handler = new Handler();
Runnable runnable = new Runnable() {

@Override
public void run() {
//你要做的事
//......
System.out.println(Thread.currentThread().getName());
handler.postDelayed(runnable, 1000);
}
};

<SPAN style="FONT-FAMILY: Courier New">package com.example.demoactivity;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class TimerActivity extends Activity{
Handler handler = new Handler();
Runnable runnable = new Runnable() {

@Override
public void run() {
System.out.println("update...");
handler.postDelayed(runnable, 1000);
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.timer);

Button mButtonStart = (Button) findViewById(R.id.button1);
Button mButtonStop = (Button) findViewById(R.id.button2);

mButtonStart.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
handler.post(runnable);
}
});

mButtonStop.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
handler.removeCallbacks(runnable);
}
});
}

}</SPAN><SPAN style="FONT-FAMILY: Georgia, 'Times new roman', Times, san-serif">
</SPAN>