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我想創建一個自定義渲染器，以便在用戶單擊按鈕時顯示上下文菜單。我有它在Android和UWP工作，但iOS更加困難。當我點擊按鈕時，所有內容都運行無誤，但不會顯示UIMenuController，儘管我無法再次單擊該按鈕，就好像包含該按鈕的視圖覆蓋了防止訪問該按鈕的屏幕。我嘗試將菜單控制器附加到按鈕ContextMenuView。iOS UIMenuController Xamarin Forms的自定義渲染器
這裏的風俗Xamarin形式查看 -
public class ContextMenuView : View
{
public EventHandler MenuRequested;
public void RequestMenu(object sender)
{
if(MenuRequested != null)
{
MenuRequested(sender, EventArgs.Empty);
}
}
}
的ContextMenuView從按鈕的點擊事件實例化Main.xaml。 Main.xaml由包含正在單擊的按鈕的AbsoluteLayout組成。下面是按鈕的單擊事件 -
private void ContextMenuButton_Clicked(object sender, EventArgs e)
{
System.Diagnostics.Debug.WriteLine("Click");
var button = sender as Button;
if (_popupMenu == null)
{
_popupMenu = new ContextMenuView();
Rectangle menuPosition = new Rectangle { X = button.X, Y = button.Y, Width = 50, Height = 50 };
_popupMenu.Layout(((Button)sender).Bounds);
AbsLayout.Children.Add(_popupMenu, menuPosition);
_popupMenu.IsVisible = true;
}
else
{
Rectangle menuPosition = new Rectangle { X = button.X, Y = button.Y + button.Height, Width = 50, Height = 50 };
_popupMenu.Layout(((Button)sender).Bounds);
}
_popupMenu.RequestMenu(sender);
}
而iOS的渲染 -
public class ContextMenuViewRendererIOS : ViewRenderer<ContextMenuView, UIView>
{
private UIView _nativeControl;
private ContextMenuView _xamarinControl;
private Xamarin.Forms.AbsoluteLayout _container;
private UIView _iosView;
private nfloat _height;
private nfloat _width;
protected override void OnElementChanged(ElementChangedEventArgs<ContextMenuView> e)
{
base.OnElementChanged(e);
if (Control == null)
{
if (e.NewElement != null)
{
_xamarinControl = e.NewElement;
_xamarinControl.MenuRequested += OnMenuRequested;
}
_height = UIScreen.MainScreen.Bounds.Height;
_width = UIScreen.MainScreen.Bounds.Width;
_nativeControl = new UIView(new CGRect(0, 0, _width, _height));
SetNativeControl(_nativeControl);
}
}
private void OnMenuRequested(object sender, EventArgs e)
{
try
{
var _menu = UIMenuController.SharedMenuController;
BecomeFirstResponder();
var iterm = new UIMenuItem("John", new ObjCRuntime.Selector("MenuItemAction:"));
_menu.MenuItems = new[] { iterm };
_menu.SetTargetRect(new CGRect(10, 10, 100, 100), _nativeControl);
_menu.MenuVisible = true;
}
catch (Exception ex)
{
throw;
}
}
[Export("MenuItemAction:")]
private void MenuItemAction(UIMenuController controller)
{
System.Diagnostics.Debug.WriteLine("MenuItemAction");
}
}
在此先感謝。