安卓怎么判断手机里面是否含有某个app

/** * 检查手机上是否安装了指定的软件 * @param context * @param packageName：应用包名 * @return */public static boolean isAvilible(Context context, String packageName){    //获取packagemanager    final PackageManager packageManager = context.getPackageManager();    //获取所有已安装程序的包信息    List<PackageInfo> packageInfos = packageManager.getInstalledPackages(0);    //用于存储所有已安装程序的包名    List<String> packageNames = new ArrayList<String>();    //从pinfo中将包名字逐一取出，压入pName list中    if(packageInfos != null){        for(int i = 0; i < packageInfos.size(); i++){            String packName = packageInfos.get(i).packageName;            packageNames.add(packName);        }    }    //判断packageNames中是否有目标程序的包名，有TRUE，没有FALSE    return packageNames.contains(packageName);}