How to get Image inside drawable folder as byte array or bitmap in code behind in Xamarin

Question

Im trying to get an image, "stupidshit.png", that's in my drawable folder of my android projekt as byte array or bitmap in the Code behind of a ContenPage. I tried literally everything. Nothing is working for me...

Have you tried using `BitmapFactory.DecodeResource(Resources, Int32)` ? — hardartcore, Oct 07 '21 at 08:06
Check this answer: https://stackoverflow.com/questions/41780588/bitmapfactory-decoderesource-does-not-recognise-drawables — hardartcore, Oct 07 '21 at 08:15
Do you know what is `Context`? You need a valid `Context` object in order to get a `Resources` object and pass it to `BitmapFactory`. — hardartcore, Oct 07 '21 at 08:27
@hardartcore i tried Android.App.Application.Context but that doesnt have getResource... Im completely lost right now tbh... I dont know where to get a valid context object... — Kajot, Oct 07 '21 at 08:32
You need a `Context` object from an `Activity` or `Application` class if you have one declared. Where are you trying to call that? In what class? — hardartcore, Oct 07 '21 at 08:36
@hardartcore I have a ContentPage and that ContentPage has a Button. When I click the Button I want to get the picture for further usage. — Kajot, Oct 07 '21 at 08:38
Here is how to get Context in Xamarin Forms: https://stackoverflow.com/questions/25613225/get-current-activity-from-application-context-monoandroid/25614348 — hardartcore, Oct 07 '21 at 08:47
I dont understand that... there is not Forms.Context that i could assign the current activity into... — Kajot, Oct 07 '21 at 09:01

score 0 · Answer 1 · answered Oct 08 '21 at 08:28

I have a ContentPage and that ContentPage has a Button. When I click the Button I want to get the picture for further usage.

You can use DependencyService to achieve this function.

please refer to the following code:

1.create an interface in form :

public interface InGetImageService
{
     Bitmap GetBitmap();
}

2.implement interface in android:

[assembly: Dependency(typeof(GetImageService))]
namespace DependencyServiceDemos.Droid
{
    public class GetImageService : InGetImageService
    {
        public Bitmap GetBitmap()
        {
            string imagefileName = "water.png";
            // Remove the file extention from the image filename
            imagefileName = imagefileName.Replace(".jpg", "").Replace(".png", "");

            // Retrieving the local Resource ID from the name
            int id = (int)typeof(Resource.Drawable).GetField(imagefileName).GetValue(null);

            // Converting Drawable Resource to Bitmap
            var originalImage = BitmapFactory.DecodeResource(MainActivity.Instance.Resources, id);

            return originalImage;
        }
    }
}

3.call the following code when clicking button in ContentPage:

Bitmap bitmap =   DependencyService.Get<InGetImageService>().GetBitmap();

Note:

The MainActivity.Instance is a variable in MainActivity in android,please refer to the following code:

public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
{
    internal static MainActivity Instance { get; private set; }

    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        Instance = this;// assign a value

        global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
        LoadApplication(new App());
    }
}

How to get Image inside drawable folder as byte array or bitmap in code behind in Xamarin

1 Answers1