gistfile1.cs

// This file has been autogenerated from a class added in the UI designer.

using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using System.Linq;
using B2.Mobile.Common.iOS;
using BigTed;
using MonoTouch.Foundation;
using MonoTouch.UIKit;
using System.Threading;

namespace B2.Mobile.Common.Ui.iOS.Controller
{
    public class MediaCollectionViewController<THandler, TModel> : UICollectionViewController, IMediaCollectionViewController 
        where TModel : class, IMediaModel, new()  
        where THandler: CreateMediaDataHandler<TModel>
    {
        private readonly MediaCollectionDelegate<THandler, TModel> _delegate;
        private readonly int _parentId;
        private readonly THandler _dataHandler;
        private readonly bool _showDescriptionButton;
        private readonly bool _showBottomBarInsteadOfTop;
        private readonly string _albumName;
        private UIImagePickerControllerQualityType _videoQuality;
        private UILongPressGestureRecognizer _longPressGestureRecognizer;
        private UIImagePickerController _imagePicker;
        private AudioRecordingOverlay _audioRecordingOverlay;
        private AudioPlaybackOverlay _audioPlaybackOverlay;
        private ImagePickerControllerDelegate _imagePickerDelegate;
        private UIToolbar _toolbar;
        private PopoverInputController _popover;
        private CustomInputViewController _inputViewController;
        private UIBarButtonItem _cameraItem;
        private UIBarButtonItem _videoItem;
        private UIBarButtonItem _audioItem;

        public NSIndexPath DeleteIndexPath { get; set; }
        private string AlbumName { get { return _albumName; } }
        public string CurrentFullscreenPath { get; set; }

        private bool _readOnly;
        public bool ReadOnly { 
            get { return _readOnly; }
            set
            {
                _readOnly = value;
                _cameraItem.Enabled = !_readOnly;
                _audioItem.Enabled = !_readOnly;
                _videoItem.Enabled = !_readOnly;
            }
        }

        public bool Landscape
        {
            get { return InterfaceOrientation == UIInterfaceOrientation.LandscapeLeft || InterfaceOrientation == UIInterfaceOrientation.LandscapeRight; }
        }

        public VideoQuality VideoQuality 
        { 
            set { _videoQuality = GetVideoQuality(value); }
        }

        public List<MediaItem> MediaAndDescriptions { get; set; }

        public static UICollectionViewLayout GetLayout()
        {
            var imageLayout = new UICollectionViewFlowLayout
            {
                ScrollDirection = UICollectionViewScrollDirection.Vertical,
                SectionInset = new UIEdgeInsets(10, 10, 50, 10),
                MinimumInteritemSpacing = 10,
                MinimumLineSpacing = 1
            };

            return imageLayout;
        }

        public MediaCollectionViewController (int parentId, THandler dataHandler, string albumName, bool showDescription, bool showBottomBarInsteadOfTop) : base (GetLayout())
        {
            _albumName = albumName;
            _showDescriptionButton = showDescription;
            _showBottomBarInsteadOfTop = showBottomBarInsteadOfTop;
            _dataHandler = dataHandler;
            _parentId = parentId;
            _delegate = new MediaCollectionDelegate<THandler, TModel>(this);

            // CollectionBehavior
            InitializeCollectionView();
        }

        private UIImagePickerControllerQualityType GetVideoQuality(VideoQuality videoQuality)
        {
            switch (videoQuality)
            {
                case VideoQuality.High:
                    return UIImagePickerControllerQualityType.High;
                case VideoQuality.Medium:
                    return UIImagePickerControllerQualityType.Medium;
                case VideoQuality.Low:
                    return UIImagePickerControllerQualityType.Low;
                default:
                    throw new ArgumentOutOfRangeException();
            }
        }

        private void InitializeCollectionView()
        {
            CollectionView.Delegate = _delegate;
            CollectionView.ScrollEnabled = true;
            CollectionView.Bounces = true;
        }

        public override void ViewDidAppear(bool animated)
        {
            base.ViewDidAppear(animated);

            CurrentFullscreenPath = null;
        }

        public override void ViewDidLoad()
        {
            base.ViewDidLoad();

            // UI
            CollectionView.BackgroundColor = UIColor.White;

            // Kamera und andere Picker
            _cameraItem = new UIBarButtonItem(UIBarButtonSystemItem.Camera, ButtonCameraClicked);
            _videoItem = new UIBarButtonItem(UIImage.FromBundle("Images/film-7.png"), UIBarButtonItemStyle.Plain, ButtonVideoClicked);
            _audioItem = new UIBarButtonItem(UIImage.FromBundle("Images/microphone-7.png"), UIBarButtonItemStyle.Plain, ButtonAudioClicked);
            var spaceItem = new UIBarButtonItem(UIBarButtonSystemItem.FixedSpace) { Width = 20.0f };

            // Prüfen ob eine Kamera vorhanden ist (z.B. Simulator)
            if (!UIImagePickerController.IsSourceTypeAvailable(UIImagePickerControllerSourceType.Camera))
            {
                _cameraItem.Enabled = false;
                _videoItem.Enabled = false;
            }

            if (!_showBottomBarInsteadOfTop && NavigationItem != null)
            {
                NavigationItem.RightBarButtonItem = _cameraItem;
            }
            else if (_showBottomBarInsteadOfTop)
            {
                var y = View.Frame.Height - 44;
                _toolbar = new UIToolbar(new RectangleF(0, y, View.Frame.Width, 44));
                _toolbar.AutoresizingMask = UIViewAutoresizing.FlexibleTopMargin | UIViewAutoresizing.FlexibleWidth;
                _toolbar.Translucent = false;
                View.AddSubview(_toolbar);

                _toolbar.Items = new[] { _cameraItem, spaceItem, _videoItem, spaceItem, _audioItem };
            }

            // Layout
            EdgesForExtendedLayout = UIRectEdge.None;


            // Cell Klasse registrieren
            CollectionView.RegisterClassForCell (typeof(ImageDescriptionCell), new NSString("imagePortraitCell"));
            CollectionView.RegisterClassForCell (typeof(ImageDescriptionCell), new NSString("imageLandscapeCell"));

            // Gesten Registrieren
            _longPressGestureRecognizer = new UILongPressGestureRecognizer(LongPressOnCell);
            CollectionView.AddGestureRecognizer(_longPressGestureRecognizer);

            // Datasource
            MediaAndDescriptions = new List<MediaItem>();

            // Bilder laden
            LoadMediaAndDescriptions();
        }

        public override void DidRotate(UIInterfaceOrientation fromInterfaceOrientation)
        {
            base.DidRotate(fromInterfaceOrientation);

            //LoadMediaAndDescriptions();
            CollectionView.ReloadData();
        }

        private void LongPressOnCell(UIGestureRecognizer gestureRecognizer)
        {
            if (ReadOnly)
                return;

            if (gestureRecognizer.State != UIGestureRecognizerState.Began)
                return;

            DeleteIndexPath = CollectionView.IndexPathForItemAtPoint(gestureRecognizer.LocationInView(CollectionView));
            if (DeleteIndexPath == null)
                return;

            var cell = CollectionView.CellForItem(DeleteIndexPath);
            if (cell == null)
                return;

            cell.BecomeFirstResponder();

            var deleteMenuItem = new UIMenuItem("Löschen", new MonoTouch.ObjCRuntime.Selector("deleteCellSelector"));
            var menuController = UIMenuController.SharedMenuController;
            menuController.MenuItems = new[] { deleteMenuItem };
            menuController.SetTargetRect(cell.Frame, cell.Superview);
            menuController.SetMenuVisible(true, true);
        }

        [Export("deleteCellSelector")]
        public void DeleteCellSelector()
        {
            var selectedItem = MediaAndDescriptions[DeleteIndexPath.Row];
            var model = _dataHandler.Get(i => i.ParentId == _parentId && i.Pfad == selectedItem.Pfad);
            _dataHandler.Delete(model);

            LoadMediaAndDescriptions();
        }

        public void ButtonCameraClicked(object sender, EventArgs eventArgs)
        {
            if (_imagePicker == null)
            {
                _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, () => { Thread.Sleep(2000); });
        }

        public void ButtonVideoClicked(object sender, EventArgs eventArgs)
        {
            if (!AudioHelper.IsAudioRecordingAvailable())
            {
                new UIAlertView("Audio", "Der Zugriff auf das Mikrofon wurde verweigert. Bitte in den Geräteeinstellungen zulassen, ansonsten enthält das Video keinen Ton", null, "Schliessen").Show();

                //                else if (UIDevice.CurrentDevice.IsiOS8())
                //                {
                //                    var alert = new UIAlertView("Zugriff Verweigert", "Der Zugriff auf das Mikrofon wurde verweigert. Bitte in den Geräteeinstellungen zulassen", null, "Schliessen", "Einstellungen");
                //                    alert.Clicked += (sender, e) => 
                //                    {
                //                        if (e.ButtonIndex == 1 && UIApplication.SharedApplication.CanOpenUrl(NSUrl.FromString(UIApplication.OpenSettingsUrlString)))
                //                        {
                //
                //                        }
                //                    };
                //                    alert.Show();
                //                }
            }

            const UIImagePickerControllerSourceType cameraType = UIImagePickerControllerSourceType.Camera;
            if(HasVideoSupport())
            {
                _imagePicker = new UIImagePickerController();
                _imagePicker.SourceType = cameraType;
                _imagePicker.MediaTypes = new []{"public.movie"} ;
                _imagePicker.VideoQuality = _videoQuality;
                _imagePicker.Delegate = new VideoImagePickerDelegate(this);

                PresentViewController(_imagePicker, true, null);
            }
            else
            {
                using (var alert = new UIAlertView("Video", "Videoaufnahme wird nicht unterstützt.", null, "Schliessen", null))
                {
                    alert.Show();
                }
            }
        }

        private bool HasVideoSupport()
        {
            var cameraType = UIImagePickerControllerSourceType.Camera;
            var cameraSupport = UIImagePickerController.IsSourceTypeAvailable(cameraType);
            return (cameraSupport) && UIImagePickerController.AvailableMediaTypes(cameraType).Contains("public.movie");
        }

        public void PlayAudio(string pfad)
        {
            _audioPlaybackOverlay = new AudioPlaybackOverlay(pfad, View.Bounds);
            _audioPlaybackOverlay.AutoresizingMask = ~UIViewAutoresizing.None;
            View.AddSubview(_audioPlaybackOverlay);
        }

        public void ButtonAudioClicked(object sender, EventArgs eventArgs)
        {
            if (!AudioHelper.IsAudioRecordingAvailable())
            {
                new UIAlertView("Zugriff Verweigert", "Der Zugriff auf das Mikrofon wurde verweigert. Bitte in den Geräteeinstellungen zulassen", null, "Schliessen").Show();

                //                else if (UIDevice.CurrentDevice.IsiOS8())
                //                {
                //                    var alert = new UIAlertView("Zugriff Verweigert", "Der Zugriff auf das Mikrofon wurde verweigert. Bitte in den Geräteeinstellungen zulassen", null, "Schliessen", "Einstellungen");
                //                    alert.Clicked += (sender, e) => 
                //                    {
                //                        if (e.ButtonIndex == 1 && UIApplication.SharedApplication.CanOpenUrl(NSUrl.FromString(UIApplication.OpenSettingsUrlString)))
                //                        {
                //
                //                        }
                //                    };
                //                    alert.Show();
                //                }

                return;
            }

            var filename = string.Format("{0}_{1}", _albumName, DateTime.Now.ToString("yyyy-MM-dd_HH-mm-ss.aac"));
            _audioRecordingOverlay = new AudioRecordingOverlay(filename, View.Bounds);
            _audioRecordingOverlay.AutoresizingMask = ~UIViewAutoresizing.None;
            _audioRecordingOverlay.ClosedAction = AudioRecordingClosed;
            View.AddSubview(_audioRecordingOverlay);
        }

        private void AudioRecordingClosed(string path)
        {
            UIApplication.SharedApplication.IdleTimerDisabled = false;

            if (string.IsNullOrWhiteSpace(path))
                return;

            BTProgressHUD.Show("Audio wird gespeichert...");
            MediaSaved(path, MediaType.Audio);
        }

        private void MediaSaved(string assetUrl, MediaType mediaTyp)
        {
            BTProgressHUD.Dismiss();

            if (assetUrl != null)
            {
                _dataHandler.CreateMediaModel(assetUrl, _parentId, mediaTyp);

                LoadMediaAndDescriptions(); 
            }
            else
            {
                // Todo Show Error
            }
        }

        private void LoadMediaAndDescriptions()
        {
            MediaAndDescriptions.Clear();

            var medien = _dataHandler.GetAll(i => i.ParentId == _parentId);

            foreach (var media in medien)
            {
                UIImage image = null;
                if (media.MediaTyp == MediaType.Image || media.MediaTyp == MediaType.Video)
                {
                    image = ImageHelper.GetImage(media.Pfad, true);

                    if (image == null)
                    {
                        _dataHandler.Delete(media);
                        continue;
                    }
                }
                else if (media.MediaTyp == MediaType.Audio)
                {
                    image = UIImage.FromBundle("Images/audio.png");

                    if (!File.Exists(media.Pfad))
                    {
                        _dataHandler.Delete(media);
                        continue;
                    }
                }

                var mediaItem = new MediaItem { Id = media.Id, Beschreibung = media.Bezeichnung, Bild = image, MediaTyp = media.MediaTyp, Pfad = media.Pfad };
                MediaAndDescriptions.Add(mediaItem);
            }

            CollectionView.ReloadData();
        }

        public override int NumberOfSections(UICollectionView collectionView)
        {
            return 1;
        }

        public override int GetItemsCount(UICollectionView collectionView, int section)
        {
            return MediaAndDescriptions.Count;
        }

        public override UICollectionViewCell GetCell(UICollectionView collectionView, NSIndexPath indexPath)
        {
            var cell = (Landscape)
                ? collectionView.DequeueReusableCell(new NSString("imageLandscapeCell"), indexPath) as ImageDescriptionCell
                : collectionView.DequeueReusableCell(new NSString("imagePortraitCell"), indexPath) as ImageDescriptionCell; ;

            //var cell = collectionView.DequeueReusableCell(new NSString("imageCell"), indexPath) as ImageDescriptionCell;
            if (cell == null)
                return new UICollectionViewCell();

            var data = MediaAndDescriptions[indexPath.Row];

            cell.ShowMediaDescriptionButton = _showDescriptionButton;
            cell.MediaItem = data;
            cell.Image = data.Bild;
            cell.Icon = GetMediaIcon(data.MediaTyp);
            cell.ReadOnly = ReadOnly;
            cell.Controller = this;
            cell.HasDescription = !string.IsNullOrWhiteSpace(data.Beschreibung);

            return cell;
        }

        private UIImage GetMediaIcon(MediaType mediaType)
        {
            switch (mediaType)
            {
                case MediaType.Image:
                    return UIImage.FromBundle("Images/camera-7.png");
                case MediaType.Video:
                    return UIImage.FromBundle("Images/film-7.png");
                case MediaType.Audio:
                    return UIImage.FromBundle("Images/microphone-7.png");
                default:
                    throw new ArgumentOutOfRangeException();
            }
        }

        public void SaveDescriptionAction(string description)
        {
            if (string.IsNullOrWhiteSpace(CurrentFullscreenPath))
                return;

            var model = _dataHandler.Get(i => i.ParentId == _parentId && i.Pfad == CurrentFullscreenPath);
            if (model == null)
                return;

            model.Version = DateTime.Now;
            model.Bezeichnung = description;
            _dataHandler.InsertOrUpdate(model);
            _dataHandler.UpdateParentVersion(_parentId);

            LoadMediaAndDescriptions();
        }

        public class ImagePickerControllerDelegate : UIImagePickerControllerDelegate
        {
            private readonly MediaCollectionViewController<THandler, TModel> _controller;

            public ImagePickerControllerDelegate(MediaCollectionViewController<THandler, TModel> controller)
            {
                _controller = controller;
            }

            public override void Canceled(UIImagePickerController picker)
            {
                picker.DismissViewController(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);
            }
        }

        public class VideoImagePickerDelegate : UIImagePickerControllerDelegate
        {
            MediaCollectionViewController<THandler, TModel> _controller;
            public VideoImagePickerDelegate(MediaCollectionViewController<THandler, TModel> controller)
            {
                _controller = controller; 
            }

            public override void Canceled (UIImagePickerController picker)
            {
                picker.DismissViewController(true, null);
            }

            public override void FinishedPickingMedia (UIImagePickerController picker, NSDictionary info)
            {
                var mediaUrlKey = new NSString("UIImagePickerControllerMediaURL");
                var mediaPath = (NSUrl) info.ObjectForKey(mediaUrlKey);
                if(mediaPath != null)
                {
                    if(UIVideo.IsCompatibleWithSavedPhotosAlbum(mediaPath.Path))
                    {
                        BTProgressHUD.Show("Video wird gespeichert...");
                        VideoHelper.SaveToCustomPhotosAlbum(mediaPath, _controller.AlbumName, _controller.MediaSaved);
                    }
                    else
                    {
                        using (var alert = new UIAlertView("Video", "Video konnte nicht gespeichert werden", null, "Schliessen", null))
                        {
                            alert.Show();
                        }
                    }
                }
                _controller.DismissViewController(true, null);
            }
        }

        public void ShowDescription(MediaItem mediaItem, UICollectionViewCell cell)
        {
            var textField = new MultiLineTextField();
            textField.AutoresizingMask = ~UIViewAutoresizing.None;
            textField.Text = mediaItem.Beschreibung;
            textField.ReadOnly = ReadOnly;
            textField.Bounces = false;
            textField.AutocapitalizationType = UITextAutocapitalizationType.Sentences;

            var imageDescriptionCell = (ImageDescriptionCell)cell;

            if (UIDevice.CurrentDevice.ModelHardware() == IOSHardware.iPad)
            {
                // In einem Popover anzeigen
                _popover = PopoverInputController.GetPopoverController(textField, "Beschreibung", () => ClosedDescription(imageDescriptionCell), null, imageDescriptionCell.ReadOnly);
                _popover.PopoverContentSize = new SizeF(400, 400);
                _popover.ShowNavigationBar = true;
                _popover.PresentFromRect(cell.Bounds, cell, UIPopoverArrowDirection.Any, true);
            }
            else // Bei unbekannten oder iPhone / iPod immer Model anzeigen
            {
                _inputViewController = CustomInputViewController.GetController(textField, "Beschreibung", () => ClosedDescription(imageDescriptionCell));

                // In einem neuen Navigation-Dialog anzeigen
                if (NavigationController != null)
                    NavigationController.PushViewController(_inputViewController, true);
                else
                    new UIAlertView("Beschreibung", "Beschreibung konnte nicht angezeigt werden, weil kein NavigationController vorliegt", null, "Schliessen", null).Show();
            }
        }

        private void ClosedDescription(ImageDescriptionCell cell)
        {
            if (_popover != null && _popover.Canceled)
                return;

            MultiLineTextField textField = null;
            if (_popover != null && _popover.View != null)
                textField = _popover.View as MultiLineTextField;
            else if (_inputViewController != null && _inputViewController.View != null)
                textField = _inputViewController.InputView as MultiLineTextField;

            if (textField == null)
                return;

            cell.MediaItem.Beschreibung = textField.Text;

            var mediaModel = _dataHandler.Get(cell.MediaItem.Id);
            mediaModel.Bezeichnung = cell.MediaItem.Beschreibung;
            _dataHandler.InsertOrUpdate(mediaModel);

            CollectionView.ReloadData();
        }
    }

    public class MediaItem
    {
        public string Beschreibung {get;set;}
        public string Pfad {get;set;}
        public UIImage Bild { get; set; }
        public MediaType MediaTyp {get;set;}
        public int Id { get; set; }
    }

    public class MediaCollectionDelegate<THandler, TModel> : UICollectionViewDelegateFlowLayout 
        where TModel : class, IMediaModel, new()  
        where THandler: CreateMediaDataHandler<TModel>
    {
        private readonly MediaCollectionViewController<THandler, TModel> _controller;

        public MediaCollectionDelegate(MediaCollectionViewController<THandler, TModel> controller)
        {
            _controller = controller;
        }

        public override void ItemSelected(UICollectionView collectionView, NSIndexPath indexPath)
        {
            var mediaItem = _controller.MediaAndDescriptions[indexPath.Row];
            _controller.DeleteIndexPath = indexPath;
            _controller.CurrentFullscreenPath = mediaItem.Pfad;

            if (mediaItem.MediaTyp == MediaType.Image)
            {
                var fullScreenImage = ImageHelper.GetImage(_controller.CurrentFullscreenPath, false);
                var fullScreenImageViewController = new FullScreenImageViewController
                {
                    Image = fullScreenImage,
                    Text = _controller.MediaAndDescriptions[indexPath.Row].Beschreibung,
                    SaveDescriptionAction = _controller.SaveDescriptionAction,
                    DeleteAction = DeleteSelectedMedia,
                    ReadOnly = _controller.ReadOnly
                };

                _controller.NavigationController.PushViewController(fullScreenImageViewController, true);
            }
            else if (mediaItem.MediaTyp == MediaType.Video)
            {
                var fullScreenVideoController = new FullScreenVideoViewController(new NSUrl(mediaItem.Pfad)) {ReadOnly = _controller.ReadOnly};
                fullScreenVideoController.DeleteAction = DeleteSelectedMedia;

                _controller.NavigationController.PushViewController(fullScreenVideoController, true);
            }
            else if (mediaItem.MediaTyp == MediaType.Audio)
            {
                _controller.PlayAudio(mediaItem.Pfad);
            }
        }

        private void DeleteSelectedMedia()
        {
            _controller.DeleteCellSelector();
        }

        public override SizeF GetSizeForItem(UICollectionView collectionView, UICollectionViewLayout layout, NSIndexPath indexPath)
        {
            float x;
            if (UIDevice.CurrentDevice.ModelHardware() == IOSHardware.iPad)
            {
                if (_controller.Landscape)
                {
                    x = collectionView.Bounds.Width / 6;
                }
                else
                {
                    x = collectionView.Bounds.Width / 5;
                }
            }
            else
            {
                if (_controller.Landscape)
                {
                    x = collectionView.Bounds.Width / 4;
                }
                else
                {
                    x = collectionView.Bounds.Width / 3;
                }
            }

            return new SizeF(x, x+40);
        }
    }
    
    public class ImageDescriptionCell : UICollectionViewCell
    {
        private UIButton _iconView;
        private UIButton _descriptionIconView;
        private UIImageView _imageView;
        private bool _hasDescription;
        //private UILabel _textLabel;

        [Export ("initWithFrame:")]
        public ImageDescriptionCell (RectangleF frame) : base (new RectangleF(frame.X, frame.Y, frame.Width, frame.Height))
        {
            InitializeUi();
        }

        private void InitializeUi()
        {
            BackgroundColor = UIColor.Clear;

            // Image
            //var imageBounds = new RectangleF(0, 0, ContentView.Bounds.Width, ContentView.Bounds.Height);
            _imageView = new UIImageView(new RectangleF(Bounds.X, Bounds.Y, Bounds.Width, Bounds.Height - 40));
            //_imageView.BackgroundColor = UIColor.Green;
            _imageView.AutoresizingMask = ~UIViewAutoresizing.None;
            //_imageView.AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleBottomMargin;
            _imageView.ContentMode = UIViewContentMode.ScaleAspectFit;
            ContentView.AddSubview(_imageView);

            // Beschreibung
            //var labelHeight = UIFont.SystemFontOfSize(UIFont.SystemFontSize).LineHeight + 10;
            //var textBounds = new RectangleF(10, ContentView.Bounds.Height - (labelHeight + 10), ContentView.Bounds.Width - 20, labelHeight);
            //_textLabel = new UILabel(textBounds);
            //_textLabel.AutoresizingMask = UIViewAutoresizing.FlexibleWidth | UIViewAutoresizing.FlexibleTopMargin;
            //_textLabel.TextAlignment = UITextAlignment.Center;
            //_textLabel.BackgroundColor = UIColor.FromRGBA(255, 255, 255, 220);
            //_textLabel.Layer.CornerRadius = 5.0f;
            //_textLabel.TextColor = UIColor.FromRGBA(0, 0, 0, 127);
            //_textLabel.Font = UIFont.ItalicSystemFontOfSize(UIFont.SystemFontSize);
            //ContentView.AddSubview(_textLabel);

            // Icon Button
            var iconFrame = new RectangleF(0, 0, 32, 32);
            _iconView = new UIButton(UIButtonType.RoundedRect);
            _iconView.Frame = iconFrame;
            _iconView.AutoresizingMask = UIViewAutoresizing.FlexibleRightMargin | UIViewAutoresizing.FlexibleBottomMargin;
            _iconView.ContentMode = UIViewContentMode.ScaleAspectFit;
            _iconView.BackgroundColor = UIColor.FromRGBA(255, 255, 255, 191);
            _iconView.Layer.CornerRadius = 5.0f;
            ContentView.AddSubview(_iconView);

            // Media description button
            //var descriptionIconFrame = new RectangleF(ContentView.Bounds.Width - 5 - 32, ContentView.Bounds.Height - 5 - 32, 32, 32);
            var descriptionIconFrame = new RectangleF(5, Bounds.Height - 5 - 32, Bounds.Width - 10, 32);
            _descriptionIconView = new UIButton(UIButtonType.RoundedRect);
            _descriptionIconView.Frame = descriptionIconFrame;
            _descriptionIconView.AutoresizingMask = UIViewAutoresizing.FlexibleRightMargin | UIViewAutoresizing.FlexibleBottomMargin;
            _descriptionIconView.ContentMode = UIViewContentMode.ScaleAspectFit;
            _descriptionIconView.Layer.CornerRadius = 5.0f;

            if (UIDevice.CurrentDevice.ModelHardware() == IOSHardware.iPad)
                _descriptionIconView.SetTitle("Beschreibung", UIControlState.Normal);

            _descriptionIconView.ImageEdgeInsets = new UIEdgeInsets(0, 0, 0, 10);
            _descriptionIconView.TitleEdgeInsets = new UIEdgeInsets(0, 10, 0, 0);
            _descriptionIconView.TouchUpInside += ShowDescription;
            ContentView.AddSubview(_descriptionIconView);
        }

        private PointF GetIconPoint(SizeF size)
        {
            if (size.Height > size.Width)
            {
                // Portrait
                var frameBorder = (ContentView.Frame.Width - (size.Width / (size.Height / ContentView.Frame.Height))) / 2;
                var x = frameBorder + 5 + 16;
                var y = 5;

                return new PointF(x, y);
            }
            else
            {
                // Portrait
                var x = 5;
                var frameBorder = (ContentView.Frame.Height - (size.Height / (size.Width / ContentView.Frame.Width))) / 2;
                var y = frameBorder + 5 - 16;

                return new PointF(x, y);
            }
        }

        private void ShowDescription(object sender, EventArgs e)
        {
            Controller.ShowDescription(MediaItem, this);
        }

        public bool HasDescription
        {
            get { return _hasDescription; }
            set
            {
                _hasDescription = value;
                var icon = (_hasDescription) ? UIImage.FromBundle("Images/document-7.png") : UIImage.FromBundle("Images/document-empty-7.png");
                _descriptionIconView.SetImage(icon, UIControlState.Normal);
            }
        }

        public IMediaCollectionViewController Controller { get; set; }

        public override bool CanBecomeFirstResponder
        {
            get
            {
                return true;
            }
        }

        public UIImage Image 
        {
            set 
            {
                if (_imageView != null)
                {
                    if (value != null)
                    {
                        //var image = value.Scale(new SizeF(Bounds.Width, Bounds.Height));
                        _imageView.Image = value;

                        var point = GetIconPoint(value.Size);
                        _iconView.Frame = new RectangleF(point, new SizeF(32, 32));
                    }
                }
            }
        }

        public bool ReadOnly { get; set; }

        public MediaItem MediaItem { get; set; }

        public bool ShowMediaDescriptionButton { get; set; }

        public UIImage Icon
        {
            set
            {
                _iconView.SetImage(value, UIControlState.Normal);
            }
        }
    }

    public interface IMediaCollectionViewController
    {
        void ShowDescription(MediaItem mediaItem, UICollectionViewCell cell);
    }
}

I saw this in StackExchange but can't comment yet.

http://stackoverflow.com/questions/26508857/uiimagepickercontroller-show-black-screen-for-every-second-shot

I'm experiencing this same exact issue (iOS 8.1 on iPhone 6). Even a dead simple test app does it. The built-in Messages app also has the same behavior. Open Messages and take a picture inside the app to send to someone. Then immediately take another one. I'm seeing a black screen, and sometimes even the previous photo I took instead of the live preview! Also of note, I'm only able to reproduce the problem on my iPhone 6. My iPhone 5s doesn't seem to have the same behavior.

Did you find a solution for your problem ? indeed i have an app which launch the camera. On iphone 6 version 8.1.2, i have users reporting that when taking a photo, the first one is ok but when trying the second time, they get a black screen, they recover once they restart the app but fall in the same situation when taking again a second photo. What's strange is that other users did not report the issue with same iphone and test condition ! i am launching the camera from a tool bar button (bottom).