CODEWITHSUNDEEP
iosxamarin.iosxamarinios8uiimagepickercontroller
dannyyy
dannyyy

Reputation: 1784

UIImagePickerController show black screen for every second shot

On all iOS 8 devices I'm facing a new issue when I'm using the UIImagePickerController (on iOS 7 it's working fine). The first shot works as expected. When I try to to take another photo the UIImagePickerController appears but shows a black screen.

All the controls such as switch camera, cancel and take photo button are available and working. If I try to make the second photo and touch the button I get a correct preview of the taken photo. If I save that photo and try to make another one all behaves as expected. Only the fourth photo has the same issue again. And so on...

This is my code:

public void ButtonCameraClicked(object sender, EventArgs eventArgs)
{
    _imagePickerDelegate = new ImagePickerControllerDelegate(this);
    _imagePicker = new UIImagePickerController();
    _imagePicker.ImagePickerControllerDelegate = _imagePickerDelegate;

    if (UIImagePickerController.IsSourceTypeAvailable(UIImagePickerControllerSourceType.Camera))
        _imagePicker.SourceType = UIImagePickerControllerSourceType.Camera;
    else
        _imagePicker.SourceType = UIImagePickerControllerSourceType.PhotoLibrary;

    PresentViewController(_imagePicker, true, null);
}

public override void FinishedPickingMedia(UIImagePickerController picker, NSDictionary info)
{
    BTProgressHUD.Show("Bild wird gespeichert...");
    var image = (UIImage)info.ObjectForKey(new NSString("UIImagePickerControllerOriginalImage"));
    image.SaveToCustomPhotosAlbum(info[UIImagePickerController.MediaMetadata] as NSDictionary, _controller.AlbumName, _controller.MediaSaved);
    picker.DismissViewController(true, null);
}

I've already googled a lot an tried the following things without any success

Initializing just once

if (_imagePicker == null)
{
    _imagePickerDelegate = new ImagePickerControllerDelegate(this);
    _imagePicker = new UIImagePickerController();
    _imagePicker.ImagePickerControllerDelegate = _imagePickerDelegate;
}

Or using a completion block

PresentViewController(_imagePicker, true, () => { });

PresentViewController(_imagePicker, true, () => { Thread.Sleep(300); });

Or synchronising to main thread

InvokeOnMainThread(() => { ... });` 
`NSOperationQueue.MainQueue.AddOperation(() => { ... });

The whole code file is available on: https://gist.github.com/anonymous/83a855d44d697235849b

Upvotes: 2

Views: 1545

Answers (1)

ClintL
ClintL

Reputation: 1453

I tried everything you tried and then decided to go a different route. The Xamarin.Mobile component on the component store not only provides a cross platform implementation of camera but in my testing was not subject to the same iOS 7+ black preview screen problem.

Sample Usage from https://components.xamarin.com/gettingstarted/xamarin.mobile

using Xamarin.Media;
using System.Threading;
using System.Threading.Tasks;
//...


var picker = new MediaPicker();
MediaPickerController controller = picker.GetTakePhotoUI (new StoreCameraMediaOptions {
   Name = "test.jpg",
   Directory = "MediaPickerSample"
});

// On iPad, you'll use UIPopoverController to present the controller
PresentViewController (controller, true, null);

controller.GetResultAsync().ContinueWith (t => {
// Dismiss the UI yourself
   controller.DismissViewController (true, () => {
    //might want to add if(t.Result.Status = task.enumstatus.rantocompletion)
    //or camera cancels will throw exceptions
    MediaFile file = t.Result;
    });

}, TaskScheduler.FromCurrentSynchronizationContext());

Upvotes: 0

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