Is there a way to use the camera functions in Xamarin Forms without downloading any extra NuGet Packages? - xamarin.forms

Question

I am currently building a project which allows the user to take a photo of something and use that photo. I was wondering if there were any other methods out there that does not require me to download any Plugins or NuGet Packages?

Answer 1

You need to create a ICameraPickerService in Xamarin Forms :
public interface IPhotoPickerService
{
Task<byte[]> GetImageStreamAsync();
}
In iOS , create the CameraPickerService :
[assembly: Dependency(typeof(CameraPickerService))]
namespace DependencyServiceDemos.iOS
{
public class CameraPickerService: ICameraPickerService
{
TaskCompletionSource<byte[]> taskCompletionSource;
UIImagePickerController imagePicker;
public Task<byte[]> GetImageStreamAsync()
{
// Create and define UIImagePickerController
imagePicker = new UIImagePickerController
{
SourceType = UIImagePickerControllerSourceType.Camera,
MediaTypes = UIImagePickerController.AvailableMediaTypes(UIImagePickerControllerSourceType.Camera)
};
// Set event handlers
imagePicker.FinishedPickingMedia += OnImagePickerFinishedPickingMedia;
imagePicker.Canceled += OnImagePickerCancelled;
// Present UIImagePickerController;
UIWindow window = UIApplication.SharedApplication.KeyWindow;
var viewController = window.RootViewController;
viewController.PresentModalViewController(imagePicker, true);
// Return Task object
taskCompletionSource = new TaskCompletionSource<byte[]>();
return taskCompletionSource.Task;
}
void OnImagePickerFinishedPickingMedia(object sender, UIImagePickerMediaPickedEventArgs args)
{
UIImage image = args.EditedImage ?? args.OriginalImage;
if (image != null)
{
// Convert UIImage to .NET Stream object
NSData data;
if (args.ReferenceUrl.PathExtension.Equals("PNG") || args.ReferenceUrl.PathExtension.Equals("png"))
{
data = image.AsPNG();
}
else
{
data = image.AsJPEG(1);
}
Stream stream = data.AsStream();
UnregisterEventHandlers();
// Set the Stream as the completion of the Task
taskCompletionSource.SetResult(data.ToArray());
}
else
{
UnregisterEventHandlers();
taskCompletionSource.SetResult(null);
}
imagePicker.DismissModalViewController(true);
}
void OnImagePickerCancelled(object sender, EventArgs args)
{
UnregisterEventHandlers();
taskCompletionSource.SetResult(null);
imagePicker.DismissModalViewController(true);
}
void UnregisterEventHandlers()
{
imagePicker.FinishedPickingMedia -= OnImagePickerFinishedPickingMedia;
imagePicker.Canceled -= OnImagePickerCancelled;
}
}
}
Not forgetting to add permission in Info.plist :
<key>NSCameraUsageDescription</key>
<string>Use Camera</string>
In addition , iOS need to run in a physical device.
In Android , create the CameraPickerService :
[assembly: Dependency(typeof(CameraPickerService))]
namespace DependencyServiceDemos.Droid
{
public class CameraPickerService : ICameraPickerService
{
public Task<byte[]> GetImageStreamAsync()
{
// Define the Intent for getting images
Intent getImageByCamera = new Intent("android.media.action.IMAGE_CAPTURE");
// Start the camera (resumes in MainActivity.cs)
MainActivity.Instance.StartActivityForResult(
getImageByCamera,
MainActivity.PickImageId);
// Save the TaskCompletionSource object as a MainActivity property
MainActivity.Instance.PickImageTaskCompletionSource = new TaskCompletionSource<byte[]>();
// Return Task object
return MainActivity.Instance.PickImageTaskCompletionSource.Task;
}
}
}
Adding permission in AndroidMainfest.xml :
<uses-permission android:name= "android.permission.CAMERA" />
<uses-permission android:name= "android.permission.WRITE_EXTERNAL_STORAGE" />
Get Image data in MainActivity :
public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
{
internal static MainActivity Instance { get; private set; }
public int CAMERA_JAVA_REQUEST_CODE = 1;
protected override void OnCreate(Bundle savedInstanceState)
{
TabLayoutResource = Resource.Layout.Tabbar;
ToolbarResource = Resource.Layout.Toolbar;
base.OnCreate(savedInstanceState);
Instance = this;
global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
LoadApplication(new App());
DependencyService.Register<ITextToSpeechService, TextToSpeechService>();
}
// Field, property, and method for Picture Picker
public static readonly int PickImageId = 1000;
public TaskCompletionSource<byte[]> PickImageTaskCompletionSource { set; get; }
protected override void OnActivityResult(int requestCode, Result resultCode, Intent intent)
{
base.OnActivityResult(requestCode, resultCode, intent);
if (requestCode == PickImageId)
{
if ((resultCode == Result.Ok) && (intent != null))
{
Bundle bundle = intent.Extras;
Bitmap bitmap = (Bitmap)bundle.Get("data");
//// Set the Stream as the completion of the Task
MemoryStream memoryStream = new MemoryStream();
bitmap.Compress(Bitmap.CompressFormat.Jpeg, 50, memoryStream);
PickImageTaskCompletionSource.SetResult(memoryStream.ToArray());
}
else
{
PickImageTaskCompletionSource.SetResult(null);
}
}
}
}
Finally , show image in ContentPage of Forms :
async void OnPickPhotoButtonClicked(object sender, EventArgs e)
{
(sender as Button).IsEnabled = false;
byte[] data = await DependencyService.Get<IPhotoPickerService>().GetImageStreamAsync();
MemoryStream stream = new MemoryStream(data);
if (stream != null)
{
image.Source = ImageSource.FromStream(() => stream) ;
}
(sender as Button).IsEnabled = true;
}
The effect :
Note : If want to pick a Photo from the Picture Library, you can have a look at this official document .