Android计时器chronometer使用实例讲解

package com.example.android.apis.view;// Need the following import to get access to the app resources, since this// class is in a sub-package.import com.example.android.apis.R;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 {  Chronometer mChronometer;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.chronometer);    Button button;    mChronometer = (Chronometer) findViewById(R.id.chronometer);    // Watch for button clicks.    button = (Button) findViewById(R.id.start);    button.setOnClickListener(mStartListener);//对应的是开始计时    button = (Button) findViewById(R.id.stop);    button.setOnClickListener(mStopListener); //对应的是停止计时    button = (Button) findViewById(R.id.reset);    button.setOnClickListener(mResetListener);//对应的是重新置数    button = (Button) findViewById(R.id.set_format);    button.setOnClickListener(mSetFormatListener);//对应的是设置时间的显示格式    button = (Button) findViewById(R.id.clear_format);    button.setOnClickListener(mClearFormatListener);//对应的是使用非格式的计时显示功能  }  View.OnClickListener mStartListener = new OnClickListener() {    public void onClick(View v) {      mChronometer.start();    }  };  View.OnClickListener mStopListener = new OnClickListener() {    public void onClick(View v) {      mChronometer.stop();     }  };  View.OnClickListener mResetListener = new OnClickListener() {    public void onClick(View v) {      mChronometer.setBase(SystemClock.elapsedRealtime());    }  };  View.OnClickListener mSetFormatListener = new OnClickListener() {    public void onClick(View v) {      mChronometer.setFormat("Formatted time (%s)");    }  };  View.OnClickListener mClearFormatListener = new OnClickListener() {    public void onClick(View v) {      mChronometer.setFormat(null);    }  };}