希望能帮到你。我正在使用 Xamarin for Visual Studio 2013。
我在 View Controller 上有一个 Collection View ，它将来自网络服务的数据加载到页面上的单元格中。这工作正常，数据在开始时正确显示。
滚动列表时，单元格会随机改变颜色。
任何人都可以看出为什么会发生这种情况吗？我们在此处 (CollectionView Highlights incorrect Cell When Scrolling) 上看到了示例，但似乎没有一个与此特定问题相关。
我很乐意澄清任何事情。
代码如下:
UIViewController
public partial class UIVCKitchenView : UIViewController
{
public static readonly EndpointAddress EndPoint = new EndpointAddress("");
private CateringServiceClient _client;
public List<KitchenViewWard> wards = new List<KitchenViewWard>();
public UIVCKitchenView (IntPtr handle) : base (handle)
{
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
InitializeHelloWorldServiceClient();
//todo:pass code from prefrences
_client.GetListAsync("01");
}
partial void TmpK_TouchUpInside(UIButton sender)
{
}
private static BasicHttpBinding CreateBasicHttp()
{
BasicHttpBinding binding = new BasicHttpBinding
{
Name = "basicHttpBinding",
MaxBufferSize = 2147483647,
MaxReceivedMessageSize = 2147483647
};
TimeSpan timeout = new TimeSpan(0, 0, 30);
binding.SendTimeout = timeout;
binding.OpenTimeout = timeout;
binding.ReceiveTimeout = timeout;
return binding;
}
private void InitializeHelloWorldServiceClient()
{
BasicHttpBinding binding = CreateBasicHttp();
_client = new CateringServiceClient(binding, EndPoint);
_client.GetKitchenWardListCompleted += _client_GetKitchenWardListCompleted;
}
void _client_GetKitchenWardListCompleted(object sender, GetKitchenWardListCompletedEventArgs e)
{
if (e.Error != null)
{
BeginInvokeOnMainThread(() =>
{
//Create Alert
var okAlertController = UIAlertController.Create("Problem", e.Error.Message, UIAlertControllerStyle.Alert);
//Add Action
okAlertController.AddAction(UIAlertAction.Create("Ok", UIAlertActionStyle.Default, null));
// Present Alert
PresentViewController(okAlertController, true, null);
});
}
else if (e.Cancelled)
{
// txtResult.Text = "Request was cancelled.";
}
else
{
List<KitchenWardList> _items = new List<KitchenWardList>(e.Result);
foreach (KitchenWardList item in _items)
{
KitchenViewWard _ward = new KitchenViewWard();
_ward.WardName = item.WardName;
_ward.WardStatus = item.WardStatus.ToString();
_ward.WardStatusId = Convert.ToInt32(item.WardStatus);
wards.Add(_ward);
}
BeginInvokeOnMainThread(() =>
{
UICVKitchenViewWards.RegisterClassForCell(typeof(UICVCKitchenViewWardsCell), UICVCKitchenViewWardsCell.CellID);
UICVKitchenViewWards.Source = new UICVCKitchenViewWardsSource(wards);
UICVKitchenViewWards.Delegate = new UICVKitchenViewWardsDelegate();
});
}
}
}
UICollectionViewSource 类 UIVCCKitchenViewWardsSource : UICollectionViewSource {
public UIStoryboard MainStoryboard
{
get { return UIStoryboard.FromName("Main", NSBundle.MainBundle); }
}
//Creates an instance of viewControllerName from storyboard
public UIViewController GetViewController(UIStoryboard storyboard, string viewControllerName)
{
return storyboard.InstantiateViewController(viewControllerName);
}
public List<KitchenViewWard> rows { get; set; }
public UICVCKitchenViewWardsSource(List<KitchenViewWard> _rows)
{
rows = _rows;
}
public override nint NumberOfSections(UICollectionView collectionView)
{
return 1;
}
public override nint GetItemsCount(UICollectionView collectionView, nint section)
{
return rows.Count;
}
public override bool ShouldHighlightItem(UICollectionView collectionView, NSIndexPath indexPath)
{
return true;
}
public override void ItemHighlighted(UICollectionView collectionView, NSIndexPath indexPath)
{
var cell = (UICVCKitchenViewWardsCell)collectionView.CellForItem(indexPath);
//cell.BackgroundColor = UIColor.Yellow;
}
public override void ItemUnhighlighted(UICollectionView collectionView, NSIndexPath indexPath)
{
//var renderer = Platform.GetRenderer(page);
var cell = (UICVCKitchenViewWardsCell)collectionView.CellForItem(indexPath);
var UIVCKitchenViewController = GetViewController(MainStoryboard, "UIVCKitchenView");
UIVCKitchenViewController.PerformSegue("seqShowKitchenDetails", this);
//cell.BackgroundColor = UIColor.Orange;
}
public override void ItemSelected(UICollectionView collectionView, NSIndexPath indexPath)
{
var cell = (UICVCKitchenViewWardsCell)collectionView.CellForItem(indexPath);
var UIVCKitchenViewController = GetViewController(MainStoryboard, "UIVCKitchenView");
UIVCKitchenViewController.PerformSegue("seqShowKitchenDetails", this);
}
public override UICollectionViewCell GetCell(UICollectionView collectionView, NSIndexPath indexPath)
{
var cell = (UICVCKitchenViewWardsCell)collectionView.DequeueReusableCell(UICVCKitchenViewWardsCell.CellID, indexPath);
cell.updateCell(rows[indexPath.Row]);
return cell;
}
}
UICollectionViewCell
public partial class UICVCKitchenViewWardsCell : UICollectionViewCell
{
public UILabel wardName;
public static NSString CellID = new NSString("UICVCKitchenViewWardsCell");
[Export("initWithFrame:")]
public UICVCKitchenViewWardsCell(CGRect frame)
: base(frame)
{
ContentView.BackgroundColor = new UIColor(225f / 255f, 225f / 255f, 225f / 255f, 1f);
ContentView.Layer.BorderWidth = 1.0f;
ContentView.Layer.BorderColor = new CGColor(0f / 255f, 134f / 255f, 255f / 255f);
wardName = new UILabel();
ContentView.AddSubviews(new UIView[] { wardName });
}
public void updateCell(KitchenViewWard ward)
{
wardName.Text = ward.WardName;
wardName.Frame = new CGRect(10, 25, ContentView.Bounds.Width - 20, 21);
switch (ward.WardStatusId)
{
case (int)WardOrderStatus.InProcess:
ContentView.BackgroundColor = new UIColor(255f / 255f, 204f / 255f, 0f / 255f, 1f);
break;
case (int)WardOrderStatus.Loaded:
ContentView.BackgroundColor = new UIColor(255f / 255f, 149f / 255f, 0f / 255f, 1f);
break;
case (int)WardOrderStatus.Nostatus:
break;
case (int)WardOrderStatus.OrderSent:
ContentView.BackgroundColor = new UIColor(90f / 255f, 200f / 255f, 250f / 255f, 1f);
break;
case (int)WardOrderStatus.Served:
ContentView.BackgroundColor = new UIColor(76f / 255f, 217f / 255f, 100f / 255f, 1f);
break;
default:
break;
}
}
}
最佳答案
在你的 UITableViewCell 子类中请覆盖 prepareForReuse()并将背景颜色设置为白色或任何默认值。
UITableViewCells 得到重用，因此当它们已经分配了颜色时，您将得到一个在出队时已经着色的单元格，而不是“新鲜”单元格。
关于c# - Xamarin CollectionView 在滚动时突出显示不正确的单元格，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41365299/