android:format;//定義時(shí)間的格式如：hh:mm:ss
 setFormat("計(jì)時(shí):%s"); //設(shè)置顯示格式
 setFormat(String format);//設(shè)置顯示時(shí)間的格式。 
start();//開始計(jì)時(shí) 
stop();//停止計(jì)時(shí)

setBase（）;//設(shè)置基地時(shí)間，一般都是SystemClock.elapsedRealtime() 
setOnChronometerTickListener(Chronometer.OnChronometerTickListener listener);//當(dāng)計(jì)時(shí)器改變時(shí)調(diào)用

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:orientation="vertical" >
  <Chronometer
    android:id="@+id/chronometer"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
   />
  <Button
    android:id="@+id/chronometer_start"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="開始計(jì)時(shí)"
  />
  <Button
    android:id="@+id/chronometer_end"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="停止計(jì)時(shí)"
     
  />
  <Button
    android:id="@+id/chronometer_null"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="重新開始計(jì)時(shí)"
     
  />
</LinearLayout>

package com.test;
 
import android.app.Activity;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Chronometer;
 
public class ChronometerDemo extends Activity {
   
  private Chronometer chronometer;
   
  private Button button_start, button_end,button_bull;
   
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
     
    setContentView(R.layout.chronometer);
     
    chronometer =(Chronometer)findViewById(R.id.chronometer);
    button_start =(Button)findViewById(R.id.chronometer_start);
    button_end =(Button)findViewById(R.id.chronometer_end);
    button_bull =(Button)findViewById(R.id.chronometer_null);
     
    button_start.setOnClickListener(clickListener);
    button_end.setOnClickListener(clickListener);
    button_bull.setOnClickListener(clickListener);
  }
 
  private OnClickListener clickListener = new OnClickListener() {
     
    @Override
    public void onClick(View v) {
       
      switch (v.getId()) {
      case R.id.chronometer_start:
        //調(diào)用start()方法開始計(jì)時(shí)
        chronometer.start();
        button_start.setText("正在計(jì)時(shí)...");
        break;
      case R.id.chronometer_end:
        //調(diào)用stop()方法停止計(jì)時(shí)
        chronometer.stop();
        button_start.setText("繼續(xù)計(jì)時(shí)");
        break;
      case R.id.chronometer_null:
        //調(diào)用stop()方法停止計(jì)時(shí)
        chronometer.setBase(SystemClock.elapsedRealtime());
        chronometer.start();
        button_start.setText("正在計(jì)時(shí)...");
        break;
 
      default:
        break;
      }
    }
  };
}