public void InitAndroid(Android.App.Activity context, Android.Content.Res.AssetManager assetMgr)
{
SDK_PlatformAndroid_InitAndroid(CoreObject, Android.Runtime.JNIEnv.Handle, assetMgr.Handle);
SDK_PlatformAndroid_SetAssetsFileNameCB(mGetAssetsRelativeFileName);
ExternalFilesDir = context.GetExternalFilesDir(null).AbsolutePath;//这个目录是app再sdcard下的沙箱目录，卸载后会被删除
//保留AssetManager
AssetManager = assetMgr;
}