public static boolean isAvilible(Context context, String packageName){
    //獲取packagemanager
    final PackageManager packageManager = context.getPackageManager();
    //獲取所有已安裝程序的包信息
    List<PackageInfo> packageInfos = packageManager.getInstalledPackages(0);
    //用於存儲所有已安裝程序的包名
    List<String> packageNames = new
 
 ArrayList<String>();
    //從pinfo中將包名字逐一取出，壓入pName list中
    if(packageInfos != null){
        for(int i = 0; i < packageInfos.size(); i++){
            String packName = packageInfos.get(i).packageName;
            packageNames.add(packName);
        }
    }
    //判斷packageNames中是否有目標程序的包名，有TRUE，沒有FALSE
 

    return packageNames.contains(packageName);
}

android檢測手機是否安裝某個app