ios - UIAlertView 不工作是 Xamarin.iOS

Question

我针对 Android 和 iOS 的 Xamarin.native 项目。我无法在 Xamarin.iOS 中显示警报；以下代码在 Xamarin.Android 上运行良好。

在 PCL 中:

public interface IDialogProvider
{
    void ShowMessage(string title, string message, string dismissButtonTitle, Action dismissed);
    void Confirm(string title, string message, string okButtonTitle, string dismissButtonTitle, Action confirmed, Action dismissed);
}

======================================

在 Xamarin.iOS 中

public class TouchDialogProvider : IDialogProvider
{
    public void ShowMessage(string title, string message, string dismissButtonTitle, Action dismissed)
    {
        var alert = UIAlertController.Create(title, message, UIAlertControllerStyle.Alert);
        alert.AddAction(UIAlertAction.Create(dismissButtonTitle, UIAlertActionStyle.Default,
        action => { if (null != dismissed) { dismissed.Invoke(); } }));
    }

public void Confirm(string title, string message, string okButtonTitle, string dismissButtonTitle, Action confirmed, Action dismissed)
{
    var alertView = new UIAlertView(title, message, null, dismissButtonTitle, okButtonTitle);
    alertView.Clicked += (object sender, UIButtonEventArgs e) => {
    if (e.ButtonIndex == 1 & null != confirmed)
        { confirmed.Invoke(); }
        if (e.ButtonIndex == 0 & null != dismissed)
            { dismissed.Invoke(); } };
    alertView.Show();
    }
}

Answer 1

您永远不会在 ShowMessage 方法中显示 View Controller :

public void ShowMessage(string title, string message, string dismissButtonTitle, Action dismissed)
{
    var alert = UIAlertController.Create(title, message, UIAlertControllerStyle.Alert);
    alert.AddAction(UIAlertAction.Create(dismissButtonTitle, UIAlertActionStyle.Default,
    action => { if (null != dismissed) { dismissed.Invoke(); } }));
    var rootVC = UIApplication.SharedApplication.Windows[0].RootViewController;
    rootVC.PresentViewController(alert, true, null);
}

另一个 Confirm 方法应该从 UIAlertView 更改为 UIAlertController，因为 UIAlertView 自 iOS 9 以来已被弃用。