Question

我正在尝试将UITapGestureRecognizer附加到UIAlertController的视图，但是识别事件永远不会触发。

我正在Xamarin中对此进行编码，但我觉得该问题也适用于本机代码。

InvokeOnMainThread(() =>

    var alert = new UIAlertController();
    alert.Title = "My Title";
    alert.Message = "My Message";

    UITapGestureRecognizer tapGestureRecognizer = new 
        UITapGestureRecognizer((gesture) =>
        {
            //I never get here
        });

    alert.View.AddGestureRecognizer(tapGestureRecognizer);
    alert.View.UserInteractionEnabled = true;

    this.PresentViewController(alert, true, null);
});

理想情况下，我想在用户触摸弹出窗口时关闭警报，但是我似乎无法检测到手势。

在尝试显示警报之前和之后，我都尝试添加识别器。

Answer 1

解决方案：

要通过单击背景视图关闭UIAlertController，可以在弹出tapGestureRecognizer时将UIAlertController添加到屏幕上的最后一个视图，检查以下代码：

public partial class ViewController : UIViewController
{
    public ViewController (IntPtr handle) : base (handle)
    {
    }

    public override void ViewDidLoad ()
    {
        base.ViewDidLoad ();
        // Perform any additional setup after loading the view, typically from a nib.

        var alert = new UIAlertController();
        alert.Title = "My Title";
        alert.Message = "My Message";

        UIAlertAction ac1 = UIAlertAction.Create("123",UIAlertActionStyle.Cancel,null);

        alert.AddAction(ac1);

        this.PresentViewController(alert, true, addGesOnBackGround);
    }

    public void addGesOnBackGround() {

        UIView backView = new UIView();

        Array arrayViews = UIApplication.SharedApplication.KeyWindow.Subviews;

        if (arrayViews.Length >0)
        {
            backView = arrayViews.GetValue(arrayViews.Length-1) as UIView;               
        }

        UITapGestureRecognizer tapGestureRecognizer = new
         UITapGestureRecognizer((gesture) =>
         {
             //I never get here
             this.DismissViewControllerAsync(true);

         });

        backView.AddGestureRecognizer(tapGestureRecognizer);
        backView.UserInteractionEnabled = true;
    }

}

UIAlertController上的UITapGestureRecognizer未触发

1 个答案: