小编典典

如何在Swift中将TextField添加到UIAlertController

swift

我正在尝试显示UIAlertController带有的UITextView。当我添加行时:

    //Add text field
    alertController.addTextFieldWithConfigurationHandler { (textField) -> Void in
    }

我收到一个Runtime错误:

致命错误:解开Optional值时意外发现nil

    let alertController: UIAlertController = UIAlertController(title: "Find image", message: "Search for image", preferredStyle: .Alert)

    //cancel button
    let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel) { action -> Void in
        //cancel code
    }
    alertController.addAction(cancelAction)

    //Create an optional action
    let nextAction: UIAlertAction = UIAlertAction(title: "Search", style: .Default) { action -> Void in
        let text = (alertController.textFields?.first as! UITextField).text
        println("You entered \(text)")
    }
    alertController.addAction(nextAction)

    //Add text field
    alertController.addTextFieldWithConfigurationHandler { (textField) -> Void in
        textField.textColor = UIColor.greenColor()
    }
    //Present the AlertController
    presentViewController(alertController, animated: true, completion: nil)

ViewController通过呈现在我的内部IBAction

我已经从这里下载了代码,并且工作正常。我将该方法复制并粘贴到我的代码中,但它中断了。最后一行的 自我 存在没有影响。


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2020-07-07

共1个答案

小编典典

因此,我开始检查看看我的代码与工作代码之间可能有什么不同。我注意到我的ViewController扩展了

UITextFieldDelegate

显然这意味着我需要设置任何子UITextView的委托:

alertController.addTextFieldWithConfigurationHandler { (textField) -> Void in
    searchTextField = textField
    searchTextField?.delegate = self //REQUIRED
    searchTextField?.placeholder = "Enter your search terms"
}
2020-07-07