Taking a screenshot in Xamarin.Forms - xamarin

Question

I've looked at and tested extensively as this post. Below is the code for a screenshot button on PCL.
async void OnScreenshotButtonClicked(object sender, EventArgs args) {
var imageSender = (Image)sender;
var ScreenShot = DependencyService.Get<IScreenshotManager>().CaptureAsync();
await DisplayAlert("Image Saved", "The image has been saved to your device's picture album.", "OK");
}
So my question is how to turn byte[] into an image and save it to a device... For the life of me, I cannot figure out a way to save the image to the device. Any help would be greatly appreciated!!! Thanks!

Answer 1

Like Jason mentioned in the comments you can extend your code in the platform project by adding a File.WriteAllBytes(); line and save your file from right there.
Or you can decouple it and create another DependencyService. For instance create the IScreenshotService like: DependencyService.Get<IScreenshotService>().SaveScreenshot("MyScreenshot123", ScreenShot);
And create implementations like this:
PCL
public interface IScreenshotService
{
SaveScreenshot(string filename, byte[] imageBytes);`
}
iOS
[assembly: Xamarin.Forms.Dependency(typeof(ScreenshotService_iOS))]
 
namespace YourApp.iOS
{
    public class ScreenshotService_iOS: IScreenshotService
{
        public void SaveScreenshot(string filename, byte[] imageBytes)
        {
            var screenshot = new UIImage(NSData.FromArray(imageBytes));
            screenshot.SaveToPhotosAlbum((image, error) =>
            {
// Catch any error here
                if(error != null)
                    Console.WriteLine(error.ToString());
// If you want you can access the image here from the image parameter
            });
        }
    }
}
Android
[assembly: Xamarin.Forms.Dependency(typeof(Picture_Droid))]
 
namespace YourApp.Droid
{
    public class ScreenshotService_Android : IScreenshotService
{
        public void SaveScreenshot(string filename, byte[] imageBytes)
        {
            var dir = Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDcim);
            
var pictures = dir.AbsolutePath;
            
// You might want to add a unique id like GUID or timestamp to the filename, else you could be overwriting an older image
            string filePath = System.IO.Path.Combine(pictures, filename);
            try
            {
// Write the image
                File.WriteAllBytes(filePath, imageData);
// With this we add the image to the image library on the device
                var mediaScanIntent = new Intent(Intent.ActionMediaScannerScanFile);
                mediaScanIntent.SetData(Uri.FromFile(new File(filePath)));
                Xamarin.Forms.Forms.Context.SendBroadcast(mediaScanIntent);
            }
            catch(Exception e)
            {
                Console.WriteLine(e.ToString());
            }
        }
    }
}
Don't forget to add the appropriate permissions on the Android app (probably WRITE_EXTERNAL_STORAGE is enough)
Lastly you could look at third-party libraries like Splat for example.