Request camera permissions xamarin forms - xamarin.forms

Question

I have an app that needs permissions for the camera, this is well implemented, but asks for permission on the home screen (splash). What I would like is to appear after logging in or on a specific page (Is this possible?). And as I could implement the same for IOS, I thank you very much for your help and have a great day.
Thanks for you help.
Here my code
MainActivity.cs
const int requestCameraId = 0;
const int requestStorageId = 1;
const int requestId = 2;
readonly string[] permissions =
{
Android.Manifest.Permission.Camera,
Android.Manifest.Permission.ReadExternalStorage,
Android.Manifest.Permission.WriteExternalStorage,
Android.Manifest.Permission.Internet,
Android.Manifest.Permission.ForegroundService,
Android.Manifest.Permission.RequestCompanionUseDataInBackground,
Android.Manifest.Permission.RequestCompanionRunInBackground,
Android.Manifest.Permission.StatusBar,
Android.Manifest.Permission.Vibrate,
Android.Manifest.Permission.Flashlight
};
public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Android.Content.PM.Permission[] grantResults)
{
switch (requestCode)
{
case requestCameraId:
{
if (grantResults[0] == (int)Android.Content.PM.Permission.Granted)
{
Toast.MakeText(this, "Permiso concedido para la camara", ToastLength.Short).Show();
}
else
{
//Permission Denied :(
Toast.MakeText(this, "Permiso denegado para la camara", ToastLength.Short).Show();
}
}
break;
case requestStorageId:
{
if (grantResults[0] == (int)Android.Content.PM.Permission.Granted)
{
Toast.MakeText(this, "Permiso concedido para el almacenamiento", ToastLength.Short).Show();
}
else
{
//Permission Denied :(
Toast.MakeText(this, "Permiso denegado para el almacenamiento", ToastLength.Short).Show();
}
}
break;
}
}
async Task GetCameraPermissionAsync()
{
const string permission = Manifest.Permission.Camera;
if (CheckSelfPermission(permission) == (int)Android.Content.PM.Permission.Granted)
{
//TODO change the message to show the permissions name
Toast.MakeText(this, "Permisos para la camara listos", ToastLength.Short).Show();
return;
}
if (ShouldShowRequestPermissionRationale(permission))
{
//set alert for executing the task
AlertDialog.Builder alert = new AlertDialog.Builder(this);
alert.SetTitle("Permisos necesarios");
alert.SetMessage("La aplicación necesita acceder a la camara para tomar una fotografía del trabajo terminado");
alert.SetPositiveButton("Conceder permiso", (senderAlert, args) =>
{
RequestPermissions(permissions, requestCameraId);
});
alert.SetNegativeButton("Cancelar", (senderAlert, args) =>
{
Toast.MakeText(this, "Cancelado", ToastLength.Short).Show();
});
Dialog dialog = alert.Create();
dialog.Show();
return;
}
}
async Task GetStoragePermissionAsync()
{
const string permission = Manifest.Permission.ReadExternalStorage;
if (CheckSelfPermission(permission) == (int)Android.Content.PM.Permission.Granted)
{
//TODO change the message to show the permissions name
Toast.MakeText(this, "Permisos para leer carpetas listos", ToastLength.Short).Show();
return;
}
if (ShouldShowRequestPermissionRationale(permission))
{
//set alert for executing the task
AlertDialog.Builder alert = new AlertDialog.Builder(this);
alert.SetTitle("Permisos necesarios");
alert.SetMessage("La aplicación necesita acceder a sus archivos para subir una imagen con el trabajo terminado");
alert.SetPositiveButton("Conceder permiso", (senderAlert, args) =>
{
RequestPermissions(permissions, requestStorageId);
});
alert.SetNegativeButton("Cancelar", (senderAlert, args) =>
{
Toast.MakeText(this, "Cancelado", ToastLength.Short).Show();
});
Dialog dialog = alert.Create();
dialog.Show();
return;
}
}
async Task GetPermissionsAsync()
{
await GetCameraPermissionAsync();
await GetStoragePermissionAsync();
RequestPermissions(permissions, requestId);
}
async Task TryToGetPermissions()
{
if ((int)Build.VERSION.SdkInt >= 23)
{
await GetPermissionsAsync();
return;
}
}
protected async override void OnCreate(Bundle savedInstanceState)
{
await TryToGetPermissions();
TabLayoutResource = Resource.Layout.Tabbar;
ToolbarResource = Resource.Layout.Toolbar;
base.OnCreate(savedInstanceState);
Xamarin.Essentials.Platform.Init(this, savedInstanceState);
// RequestPermissions(permissions, requestId);
global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
LoadApplication(new App());
Xamarin.Forms.Application.Current.On<Xamarin.Forms.PlatformConfiguration.Android>().UseWindowSoftInputModeAdjust(WindowSoftInputModeAdjust.Resize);
CreateNotificationFromIntent(Intent);
//notificationServiceIntent = new Intent(this.BaseContext, typeof(PDANotificationService));
//StartService(notificationServiceIntent);
WireUpLongRunningTask();
var message = new StartLongRunningTaskMessage();
MessagingCenter.Send(message, "StartLongRunningTaskMessage");
}

Answer 1

As #Jason said, your code requests permission on main Activity create, so as soon as you open your app, it will ask for all the permissions you listed. You need to request permission separately.
Say camera permission:
if (CheckSelfPermission(Manifest.Permission.Camera) != (int)Permission.Granted)
{
//request permission
}else
{
//call camera
}
And OnRequestPermissionsResult will be called after user granted/denied the permission request, you can check the result and call camera if the permission was granted.
Please refer to this for detail workflow about permission.