setOnClickPendingIntent()方法将绑定PendingIntent以响应按钮单击事件.

示例代码如下：

private void showControllerInNotification() {       
    PendingIntent pendingIntent = null;
    Intent intent = null;


    //Inflate a remote view with a layout which you want to display in the notification bar.
    if (mRemoteViews == null) {
        mRemoteViews = new RemoteViews(getPackageName(),R.layout.notification_control_bar);
    }   

    //Define what you want to do after clicked the button in notification.
    //Here we launcher a service by an action named "ACTION_STOP" which will stop the music play.
    intent = new Intent(ACTION_STOP);       
    pendingIntent = PendingIntent.getService(getApplicationContext(),REQUEST_CODE_STOP,intent,PendingIntent.FLAG_UPDATE_CURRENT);

    //In R.layout.notification_control_bar,there is a button view identified by bar_btn_stop
    //We bind a pendingIntent with this button view so when user click the button,it will excute the intent action.
    mRemoteViews.setOnClickPendingIntent(R.id.bar_btn_stop,pendingIntent);

    //Create the notification instance.
    mNotification = new NotificationCompat.Builder(getApplicationContext())
            .setSmallIcon(R.drawable.ic_launcher).setOngoing(true)
            .setWhen(System.currentTimeMillis())                
            .setContent(mRemoteViews)
            .build();

    //Show the notification in the notification bar.
    mNotifiManager.notify(NOTIFICATION_ID,mNotification);      
}

更新1：

响应操作的服务是这样的：

public class MediaPlayerService extends Service {

    public static final String ACTION_STOP="xxx.yyy.zzz.ACTION_STOP";
    public static final String ACTION_PLAY="xxx.yyy.zzz.ACTION_PLAY";
    public static final String ACTION_PAUSE="xxx.yyy.zzz.ACTION_PAUSE";

@Override
public int onStartCommand(Intent intent,int flags,int startId) {
    if (intent != null) {
        String action = intent.getAction();         
        if (!TextUtils.isEmpty(action)) {
            if (action.equals(ACTION_PLAY)) {
                startPlay();
            }else if(action.equals(ACTION_PAUSE)) {
                pausePlay();
            }else if(action.equals(ACTION_STOP)) {
                stopPlay();
            }
        }
    }
    return super.onStartCommand(intent,flags,startId);
}
private void stopPlay(){
    // do the play work here
}
private void stopPause(){
    // do the pause work here
}
private void stopPlay(){
    // do the stop work here
}

}

在清单中注册服务：

<service
        android:name="xxx.yyy.zzz.MusicPlayService"
        android:exported="false" >
        <intent-filter>
            <action android:name="xxx.yyy.zzz.ACTION_PLAY" />
            <action android:name="xxx.yyy.zzz.ACTION_PAUSE" />
            <action android:name="xxx.yyy.zzz.ACTION_STOP" />
            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </service>

对于音乐播放控件,您可以从here复制一些有用的代码sinppets.