.Net Maui, ability to access external sd card

Question

With the removal of read and write permissions to external storage, is there any way to access external SD cards?

My app normally relies on being able to automatically backup data to external SD cards in the event the tablet dies or is broken.

Is there any built in functionality to allow this in .Net Maui so it will still be accpeted by the Play Store?

These are custom binary files.

This is mainly for Android devices, but I would like to add to iOS as well as they can take thumb drives.

Answer 1

Hello,

I assume I have to find a way to write some platform specific code to ask for this permission?

Yes, this permission needs to open the android application settings page, then grand this permission by users.

You can use Conditional compilation for android platform code.

For example, you want to request this permission in the button click event. you can popup a SnackBar, tell user about this permission needed and let user to click.

private void OnCounterClicked(object sender, EventArgs e)
        {
#if ANDROID
            var activity=Platform.CurrentActivity;
            if (Android.OS.Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.R)
            {
                if (!Android.OS.Environment.IsExternalStorageManager)
                {
                    Google.Android.Material.Snackbar.Snackbar.Make(activity.FindViewById(Android.Resource.Id.Content), "Permission needed!", Google.Android.Material.Snackbar.Snackbar.LengthIndefinite)
                            .SetAction("Settings", new MyClickHandler()).Show();
                }
 
            }
#endif
        }

Next, you need to implement the Android.Views.View.IOnClickListener interface for SnackBar. It will open the application settings page; user need to grand the manager external permission.

#if ANDROID
    internal class MyClickHandler : Java.Lang.Object, Android.Views.View.IOnClickListener
    {

 
        public void OnClick(Android.Views.View v)
        {
            try
            {
 
                Android.Net.Uri uri = Android.Net.Uri.Parse("package:" + Platform.CurrentActivity.ApplicationInfo.PackageName);
               Android.Content.Intent intent = new Android.Content.Intent(Android.Provider.Settings.ActionManageAppAllFilesAccessPermission, uri);
                Platform.CurrentActivity.StartActivity(intent);
            }
            catch (Exception ex)
            {
                Android.Content.Intent intent = new Android.Content.Intent();
                intent.SetAction(Android.Provider.Settings.ActionManageAppAllFilesAccessPermission);
                Platform.CurrentActivity.StartActivity(intent);
            }
        }
    }
 
#endif

In the end, please open the AndroidManifest.xml and add <uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" /> permission.

Best Regards,

Leon Lu

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