Delete before shut down! c# android

Question

I want to delete all file in camera folder of my internal smartphone's storage before it goes off!

How can i do?

    namespace App1
{
    [Activity(Label = "App1", MainLauncher = true, Icon = "@drawable/icon")]
    public class MainActivity : Activity
    {
        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);        
           SetContentView (Resource.Layout.Main);

            Button delete = FindViewById<Button>(Resource.Id.deleteid);

             delete.Click += delegate
             {
                 File dir = new File(Environment.GetExternalStoragePublicDirectory(Environment.DirectoryDcim), "/Camera");

                 if (dir.IsDirectory)
                  {
                       int i = 0;
                       string[] children = dir.List();
                          while ( i < children.Length)
                       {
                        var file = new File(dir, children[i]).Delete();


                           i++;
                       }

                      Toast.MakeText(this, "The folder exist", ToastLength.Short).Show();
                  }

                  else
                  {
                      Toast.MakeText(this, "Not Works", ToastLength.Short).Show();
                  }
             };
        }
    }

}

I tried to use this code to delete the content of folder but the app crashes.

Answer 1

You need to create receiver for listen a shutdown event. For this needs you should implement class Service and don't foget to add following lines in manifest file:

<action android:name="android.intent.action.ACTION_SHUTDOWN" />
<action android:name="android.intent.action.QUICKBOOT_POWEROFF" />

Also, for delete users data, make shure that you have permissions to do that:

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />