Xamarin iOS 8, UICollectionView - Ошибка в requeable UICollectionViewCell

Question

У меня возникли проблемы с реализацией UICollectionView в моем UIViewController. Это дает мне ошибку в GetCellFailed to marshal the Objective-C object 0x137622db0 (type: ParkXApp_iOS_FamilyCollectionCell). Could not find an existing managed instance for this object, nor was it possible to create a new managed instance (because the type 'ParkXApp_iOS.FamilyCollectionCell' does not have a constructor that takes one IntPtr argument)..

Я реализовал рядом с кодом MonoTouch образца: monotouch sample simple UICollectionView

это мой код:

using System; 
using UIKit; 
using CoreGraphics; 
using System.Collections.Generic; 
using ObjCRuntime; 
using Foundation; 

namespace ParkXApp_iOS 
{ 
public class FamilyView : UIViewController 
{ 
    nfloat navBarHeight; 
    nfloat viewWidth; 
    nfloat viewHeight; 


    public FamilyView() 
    { 
    } 

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

     Draw(); 
    } 

    public void Draw() { 

     // clean the screen before (re)drawing it 
     foreach (var subView in this.View.Subviews) { 
      subView.RemoveFromSuperview(); 
     } 
     this.NavigationItem.SetRightBarButtonItem(null, true); 


     // set background 
     this.View.BackgroundColor = new UIColor((nfloat)0.99, (nfloat)0.99, (nfloat)0.99, 1); 


     // get viewWidth and viewHeight for drawing relative to the screen 
     navBarHeight = this.NavigationController.NavigationBar.Frame.GetMaxY(); 
     viewWidth = UIScreen.MainScreen.Bounds.Width; 
     viewHeight = UIScreen.MainScreen.Bounds.Height - navBarHeight; 

     UICollectionViewFlowLayout flowLayout = new UICollectionViewFlowLayout(); 
     flowLayout.ItemSize = new CGSize (100, 100); 
     flowLayout.ScrollDirection = UICollectionViewScrollDirection.Vertical; 
     flowLayout.SectionInset = new UIEdgeInsets (20, 20, 20, 20); 

     UICollectionView collectionView = new FamilyCollectionView (flowLayout).CollectionView; 
     collectionView.Frame = new CGRect (0, navBarHeight, viewWidth, viewHeight); 
     collectionView.ContentInset = new UIEdgeInsets (50, 0, 0, 0); 

     this.View.AddSubview (collectionView); 


    } 
} 


public class FamilyCollectionView : UICollectionViewController 
{ 

    List<string> familyMembers; 

    public FamilyCollectionView (UICollectionViewLayout layout) : base (layout) { 

     familyMembers = new List<string>(); 

     for (int i = 0; i < 5; i++) { 
      familyMembers.Add ("tom"); 
     } 


     CollectionView.RegisterClassForCell (typeof(FamilyCollectionCell), "FamilyCollectionCell"); 

     UIMenuController.SharedMenuController.MenuItems = new UIMenuItem[] { 
      new UIMenuItem ("Custom", new Selector ("custom")) 
     }; 
    } 

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

    public override nint GetItemsCount (UICollectionView collectionView, nint section) 
    { 
     return familyMembers.Count; 
    } 

    public override UICollectionViewCell GetCell (UICollectionView collectionView, Foundation.NSIndexPath indexPath) 
    { 
     try { 
     var cell = (FamilyCollectionCell)collectionView.DequeueReusableCell ("FamilyCollectionCell", indexPath); 

     cell.nameLabel.Text = familyMembers [indexPath.Row]; 

     return cell; 
     } catch (Exception ex) { 
      Console.WriteLine (ex.Message); 
     } 
     return null; 
    } 

    public override void ItemHighlighted (UICollectionView collectionView, NSIndexPath indexPath) 
    { 
     var cell = collectionView.CellForItem (indexPath); 
     cell.ContentView.BackgroundColor = UIColor.Yellow; 
    } 

    public override void ItemUnhighlighted (UICollectionView collectionView, NSIndexPath indexPath) 
    { 
     var cell = collectionView.CellForItem (indexPath); 
     cell.ContentView.BackgroundColor = UIColor.White; 
    } 

    public override bool ShouldHighlightItem (UICollectionView collectionView, NSIndexPath indexPath) 
    { 
     return true; 
    } 



} 

public class FamilyCollectionCell : UICollectionViewCell 
{ 
    public UILabel nameLabel; 

    public FamilyCollectionCell (CGRect frame) : base (frame) 
    { 
     BackgroundColor = UIColor.Orange; 

     ContentView.Layer.BorderColor = UIColor.LightGray.CGColor; 
     ContentView.Layer.BorderWidth = 2.0f; 
     ContentView.BackgroundColor = UIColor.White; 
     ContentView.Transform = CGAffineTransform.MakeScale (0.8f, 0.8f); 

     nameLabel = new UILabel(); 
     nameLabel.Text = "name"; 
     nameLabel.SizeToFit(); 
     nameLabel.Center = ContentView.Center; 

     ContentView.AddSubview (nameLabel); 


    } 

    [Export("custom")] 
    void Custom() 
    { 
     Console.WriteLine ("some code in the cell"); 
    } 

    public override bool CanPerform (Selector action, NSObject withSender) 
    { 
     if (action == new Selector ("custom")) 
      return true; 
     else 
      return false; 
    } 
} 
} 

Чтобы проверить это, вы должны быть в состоянии скопировать и вставить код и запустить его в растворе , Он полностью независим.

Заранее благодарен!

Answer 1

Вам нужно добавить следующее:

[Export ("initWithFrame:")] 

в вас клетке, как так

public class FamilyCollectionCell : UICollectionViewCell 
{ 
    public UILabel nameLabel; 

    [Export ("initWithFrame:")] // ADDED HERE 
    public FamilyCollectionCell (CGRect frame) : base (frame) 
    { 
     BackgroundColor = UIColor.Orange; 

     ContentView.Layer.BorderColor = UIColor.LightGray.CGColor; 
     ContentView.Layer.BorderWidth = 2.0f; 
     ContentView.BackgroundColor = UIColor.White; 
     ContentView.Transform = CGAffineTransform.MakeScale (0.8f, 0.8f); 

     nameLabel = new UILabel(); 
     nameLabel.Text = "name"; 
     nameLabel.SizeToFit(); 
     nameLabel.Center = ContentView.Center; 

     ContentView.AddSubview (nameLabel); 


    } 

    [Export("custom")] 
    void Custom() 
    { 
     Console.WriteLine ("some code in the cell"); 
    } 

    public override bool CanPerform (Selector action, NSObject withSender) 
    { 
     if (action == new Selector ("custom")) 
      return true; 
     else 
      return false; 
    } 
} 

Кроме того, что это интересный способ добавления в CollectionView в ViewController. Есть ли необходимость в FamilyView? Может быть, лучше добавить navbar в контроллер коллекции?