xamarin android broadcast receiver not working for ActionMediaMounted.

Question

Hi there

I want to be able to see when a user has mounted/removed an external drive from an android app. (It will primarily be a USB device).
I want to be able to only save data to the USB and not on the device itself.

I thought I would see if a device is mounted and if it is use the provided drive. If no device is found and the user attempts to save, then display an error asking them to plug a drive in.

Trying to find the directory for removable storage on android has proven more difficult then anticipated.

I have created an ActionMediaMounted broadcast receiver, but it never fires.
I have also created an ActionPowerConnected and ActionsPowerDisconnected broadcast receiver and these also don't seem to fire.

I figure I am probably missing some kind of permission or manifest update.

Below is an example of the Action power broadcast receiver.

[BroadcastReceiver(Enabled = true, Exported = true)]  
    [IntentFilter(new[] { Android.Content.Intent.ActionPowerConnected, Android.Content.Intent.ActionPowerDisconnected })]  
    public class PowerConnectedBroadcastReceiver : BroadcastReceiver  
    {  
        public override void OnReceive(Context context, Intent intent)  
        {  
            Toast.MakeText(context, "Received intent!", ToastLength.Short).Show();  
        }  
    }  

This is my broadcast receiver for the device mounted:

    [BroadcastReceiver(Enabled = true, Exported = true)]  
    [IntentFilter(new[] { Android.Content.Intent.ActionMediaMounted})]  
    public class ExternalStorageBroadcastReceiver : BroadcastReceiver  
    {  
        private static string TAG = "ExternalStorageBroadcastReceiver";  
  
        public override void OnReceive(Context context, Intent intent)  
        {  
            Toast.MakeText(context, $"USB plugged in fired", ToastLength.Long).Show();  
            string action = intent.Action;  
  
            if (!string.IsNullOrEmpty(action))  
            {  
                Log.Info(TAG, $"got action which is :{action}");  
                Toast.MakeText(context, $"got action which is :{action}", ToastLength.Long).Show();  
            }  
            else  
            {  
                Log.Info(TAG, "no action has been found");  
                Toast.MakeText(context, $"no action has been found", ToastLength.Long).Show();  
            }  
              
            if(Android.Content.Intent.ActionMediaMounted.Equals(action))  
            {  
                Log.Info(TAG, $"Received media mounted : {action}");  
                Toast.MakeText(context, $"Received media mounted : {action}", ToastLength.Long).Show();  
  
                if (intent != null && intent.Data != null)  
                {  
                    string mediaPathLocation = intent.Data.Path;  
  
                    if(!string.IsNullOrEmpty(mediaPathLocation))  
                    {  
                        Log.Info(TAG, $"The media uri location is : {mediaPathLocation}");  
                        Toast.MakeText(context, $"The media uri location is : {mediaPathLocation}", ToastLength.Long).Show();  
  
                       
                    }  
                }  
            }  
        }  
    }  

I read the documentation from android that said some system broadcasts would be stopped, but there is a list of excluded and the mediamounted is within that
https://developer.android.com/guide/components/broadcast-exceptions

The toasts do not display on my device.

Any ideas would be appreciatd.

Many thanks

Answer 1

Hello,

You need to add this property IntentFilter.AddDataScheme("file"); to receive the broadcast.

Would the following code helpful for you? Your early feedback will be highly appreciated.

   private void RegisterRec()  
   {  
       IntentFilter intentFilter = new IntentFilter(Intent.ActionMediaMounted);  
       intentFilter.Priority = 1000;  
       intentFilter.AddDataScheme("file");  
       RegisterReceiver(new ExternalStorageBroadcastReceiver(), intentFilter);  
   }  

Best Regards,

Alec Liu.

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