参考Is there a way to get the installer source of android app in the native android的案例。您可以将以下代码放入MainActivity的OnCreate方法中：

string installpackage;
PackageManager package = this.PackageManager;
if(Build.VERSION.SdkInt > BuildVersionCodes.R)
{
      installpackage = package.GetInstallSourceInfo(this.PackageName).InitiatingPackageName;
}
else
{
      installpackage = package.GetInstallerPackageName(this.PackageName);
}
if (installpackage == "com.android.vending") // install from the google play

如果设备上未安装Play商店，我们可以检查Google Play服务包是否存在，该服务包安装在大多数Android设备上。我们可以使用PackageInfo类获取有关Google Play服务包的信息并检查是否已安装。[1][2][3]

try 
{ 
PackageInfo info = getPackageManager().getPackageInfo("com.google.android.gms", 0); 
// Google Play services is installed 
} 
catch (PackageManager.NameNotFoundException e)
{ 
// Google Play services is not installed 
}