防止在PositiveButton上關閉UIAlertView點擊

Question

我正在使用Xamarin.Forms開發移動應用程序。我有要求在對話框中獲得輸入。所以，我已經使用UIAlertView來獲取文本輸入，如下所示。

我需要防止從UIAlertView中收盤按鈕的點擊。即使在啓動操作之後，我仍需要保留UIAlertView對話框。

任何人都可以幫助我嗎？

問候，

卡菲基恩

Answer 1

您可以創建此使用XIB文件，但是如果你不反對的對話框關閉並重新打開它應該遇到驗證問題，那麼下面將一個自定義的UIView工作正常。

編輯：調整爲允許您傳回驗證消息，作爲UIAlertView上的主要消息。

private string message = string.Empty(); 

public void recursiveDialog() 
{ 
    string input = string.Empty(); 

    if(message == string.Empty()) { message = "Please enter the view name"} 

    var alert = UIAlertController.Create ("Save View", message, UIAlertControllerStyle.Alert); 

    alert.AddTextField ((field) => { 
    field.Placeholder = "view name";}); 

    alert.AddAction (UIAlertAction.Create ("Cancel", UIAlertActionStyle.Cancel, null)); 

    alert.AddAction (UIAlertAction.Create ("Save", UIAlertActionStyle.Default, action => { 
       input = alert.TextFields[0].Text 
    })); 

    if (alert.PopoverPresentationController != null) 
     alert.PopoverPresentationController.BarButtonItem = myItem; 

    PresentViewController (alert, animated: true, 
    action => { 

     // when a dialog is selected and returns, run validation 

     if(input == [whatever you want to use to validate it against]) 
     { 
        // it failed because it already exists for example so change our message 

        message = "That view name already exists, try again."; 

      // already exists, so re-run method. 
      recursiveDialog(); 
     } 
     else 
     { 
      // doesn't alread exist so carry on with whatever you want to do with the name provided. 

        // clear your message variable 
        message = string.Empty(); 
     } 
    }); 
}