我有一个包含 8 个部分的 UIcollectionView。每个部分都有一个专用数组作为数据源。我想在按下按钮时向每个部分添加一个项目。 UICollectionView 滚动方向设置为水平，因为我希望这些部分是垂直方向。 Xcode 项目(Xib 和 Objective-C)中的一切工作正常，如此屏幕截图所示(红色项目是按下按钮时添加的项目)。
当我在 Xamarin ios 中执行相同的实现时，按下按钮后布局变得一团糟，如下所示。
我的代码如下
public partial class GridViewController : UIViewController
{
CVSource source;
int MAX_NUMBER_OF_ROWS = 4;
public GridViewController(IntPtr handle) : base(handle)
{
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
// Perform any additional setup after loading the view, typically from a nib.
//this.collectionView.SetNeedsDisplay();
this.collectionView.RegisterClassForCell(typeof(ItemCell), ItemCell.CellId);
source = new CVSource();
this.collectionView.DataSource = source;
}
partial void AddButtonPressed(UIButton sender)
{
Console.WriteLine("Add button pressed");
MAX_NUMBER_OF_ROWS = MAX_NUMBER_OF_ROWS + 1;
source.AddItem();
collectionView.Layer.RemoveAllAnimations();
collectionView.ReloadData();
ViewDidLayoutSubviews();
}
public override void ViewDidLayoutSubviews()
{
base.ViewDidLayoutSubviews();
collectionView.Frame = new CoreGraphics.CGRect(collectionView.Frame.Location.X, collectionView.Frame.Location.Y, collectionView.Frame.Size.Width, MAX_NUMBER_OF_ROWS * 40);
btnAdd.Frame = new CoreGraphics.CGRect(btnAdd.Frame.Location.X, collectionView.Frame.Location.Y + collectionView.Frame.Size.Height + 10, btnAdd.Frame.Size.Width, btnAdd.Frame.Size.Height);
}
public override void DidReceiveMemoryWarning()
{
base.DidReceiveMemoryWarning();
// Release any cached data, images, etc that aren't in use.
}
数据源类
class CVSource : UICollectionViewSource
{
List<string> arr1 = new List<string> { "40", "30"};
List<string> arr2 = new List<string> { "25", "22" };
List<string> arr3 = new List<string> { "35", "67" };
List<string> arr4 = new List<string> { "26", "12" };
List<string> arr5 = new List<string> { "27", "21", };
List<string> arr6 = new List<string> { "12", "45" };
List<string> arr7 = new List<string> { "34", "67" };
List<string> arr8 = new List<string> { "21", "44", };
public override nint NumberOfSections(UICollectionView collectionView)
{
return 8;
}
public override nint GetItemsCount(UICollectionView collectionView, nint section)
{
if ((int)section == 0)
return arr1.Count;
else if ((int)section == 1)
return arr2.Count;
else if ((int)section == 2)
return arr3.Count;
else if ((int)section == 3)
return arr4.Count;
else if ((int)section == 4)
return arr5.Count;
else if ((int)section == 5)
return arr6.Count;
else if ((int)section == 6)
return arr7.Count;
else if ((int)section == 7)
return arr8.Count;
return 0;
}
public override UICollectionViewCell GetCell(UICollectionView collectionView, Foundation.NSIndexPath indexPath)
{
var itemCell = (ItemCell)collectionView.DequeueReusableCell(ItemCell.CellId, indexPath);
if (indexPath.Section == 0)
{
itemCell.SetText(arr1[indexPath.Row]);
}
else if (indexPath.Section == 1)
{
itemCell.SetText(arr2[indexPath.Row]);
}
else if (indexPath.Section == 2)
{
itemCell.SetText(arr3[indexPath.Row]);
}
else if (indexPath.Section == 3)
{
itemCell.SetText(arr4[indexPath.Row]);
}
else if (indexPath.Section == 4)
{
itemCell.SetText(arr5[indexPath.Row]);
}
else if (indexPath.Section == 5)
{
itemCell.SetText(arr6[indexPath.Row]);
}
else if (indexPath.Section == 6)
{
itemCell.SetText(arr7[indexPath.Row]);
}
else if (indexPath.Section == 7)
itemCell.SetText(arr8[(indexPath.Row)]);
return itemCell;
}
public override void ItemSelected(UICollectionView collectionView, NSIndexPath indexPath)
{
Console.WriteLine("Row selected "+ indexPath.Row);
}
public void AddItem()
{
arr1.Add("0");
arr2.Add("0");
arr3.Add("0");
arr4.Add("0");
arr5.Add("0");
arr6.Add("0");
arr7.Add("0");
arr8.Add("0");
}
}
ItemCell 类
public partial class ItemCell : UICollectionViewCell
{
public static readonly NSString CellId = new NSString("ItemCell");
public static UITextField txtFld;
[Export("initWithFrame:")]
public ItemCell(CGRect frame) : base(frame)
{
BackgroundView = new UIView { BackgroundColor = UIColor.Orange };
SelectedBackgroundView = new UIView { BackgroundColor = UIColor.Green };
ContentView.Layer.BorderColor = UIColor.LightGray.CGColor;
ContentView.Layer.BorderWidth = 2.0f;
ContentView.BackgroundColor = UIColor.White;
ContentView.Transform = CGAffineTransform.MakeScale(0.8f, 0.8f);
txtFld = new UITextField() { Frame = new CGRect(5.0, 5.0, 60.0, 30.0), KeyboardType = UIKeyboardType.DecimalPad };
}
}
我不是 Xamarin 开发人员，感谢 Xamarin 专家的任何评论/建议
最佳答案
也许你错过了 UICollectionViewLayout 为 collectionView 设置，你可以为 collectionView 设置 GridLayout 试试看。
this.collectionView.SetCollectionViewLayout(new GridLayout(), true); //add CollectionViewLayout
this.collectionView.RegisterClassForCell(typeof(ItemCell), ItemCell.CellId);
GridLayout 继承自 Xamrarin iOS 中的 UICollectionViewFlowLayout:
public class GridLayout : UICollectionViewFlowLayout
{
public GridLayout ()
{
}
public override bool ShouldInvalidateLayoutForBoundsChange (CGRect newBounds)
{
return true;
}
public override UICollectionViewLayoutAttributes LayoutAttributesForItem (NSIndexPath path)
{
return base.LayoutAttributesForItem (path);
}
public override UICollectionViewLayoutAttributes[] LayoutAttributesForElementsInRect (CGRect rect)
{
return base.LayoutAttributesForElementsInRect (rect);
}
}
效果:
尝试共享代码后，效果如下:
与您的代码的不同之处仅在于:
public ViewController (IntPtr handle) : base (handle)
{
collectionView = new UICollectionView(new CGRect(0, 0, UIScreen.MainScreen.Bounds.Size.Width, 300), new GridLayout());
collectionView.RegisterClassForCell(typeof(ItemCell), ItemCell.CellId);
//collectionView.SetCollectionViewLayout(new GridLayout(), true);
collectionView.BackgroundColor = UIColor.Blue;
source = new CVSource();
collectionView.DataSource = source;
View.AddSubview(collectionView);
button = new UIButton(new CGRect(150, 400, 100, 50));
button.SetTitle("Hello", UIControlState.Normal);
button.BackgroundColor = UIColor.Red;
View.AddSubview(button);
button.TouchUpInside += Button_TouchUpInside;
}
注意:我使用代码创建 Interface ，并为 CollectionView 设置 GridLayout 。这里是 sample link .
关于ios - UICollectionView 与 Xamarin Native 中的部分布局问题，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/59772684/