android判断一个Service是否存在

public static boolean isServiceExisted(Context context, String className) {
    ActivityManager activityManager = (ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);
    List serviceList =activityManager.getRunningServices(Integer.MAX_VALUE);
    if(!(serviceList.size() > 0)) {
		return false;
	}
	for(int i = 0; i < serviceList.size(); i++) {
		RunningServiceInfo serviceInfo = serviceList.get(i);
		ComponentName serviceName = serviceInfo.service;
		if(serviceName.getClassName().equals(className)) {
			return true;
		}
	} 
	return false;
}