Swift UIButton 和 IBAction 在 Objective C 中崩溃

Question

我正在创建一个我用 Swift 编写的可达性警报，并在最初用目标 C 编写的应用程序中被调用。我的所有 bridged-header-.h 设置正确。当我单击在 Swift 中创建的 UIButton 和同样用 swift 编写的 IBAction 时，问题就发生了。下面是错误和代码。有没有办法防止这种崩溃？

由于未捕获的异常“NSInvalidArgumentException”而终止应用程序，原因：“-[NSNotificationQueue buttonTapped:]：无法识别的选择器已发送到实例 0x7ae602d0”

//  NetworkErrorView.swift


import Foundation
import UIKit



@objc class NetworkErrorView: NSObject {

    var xCoordinate:CGFloat = 0
    var yCoordinate: CGFloat = 0
    var width: CGFloat = 0
    var height: CGFloat = 0
    var reTryButton = UIButton()


func renderAlertView() -> UIView  {

    let alert = UIAlertView()
    alert.title = "Connection Failed"
    alert.message = "Your device is not connected to the Internet. Please try again later."
    alert.addButtonWithTitle("OK")
    alert.show()
    return alert

    }


func renderReTryButton() -> UIView {

    var buttonImage = UIImage(named: "Btn-Try-Again@2x.png")
    reTryButton.addTarget(self, action: Selector("buttonTapped:"), forControlEvents: UIControlEvents.TouchUpInside)
    reTryButton.setBackgroundImage(buttonImage, forState: UIControlState.Normal)
    reTryButton.frame = CGRect(x: 18, y: 470, width: 290, height: 30)
    println("stopes here")
    return reTryButton

    }


   @IBAction func buttonTapped (sender: AnyObject!) {

    let alertView = UIAlertView()
    alertView.title = "Connection Failed"
    alertView.message = "Your device is not connected to the Internet. Please try again later."
    alertView.addButtonWithTitle("OK")
    alertView.show()

    }

func render() -> UIView {

    var networkErrorView = UIView()

    let screenSize: CGRect = UIScreen.mainScreen().bounds

    let screenWidth = screenSize.width;

    let screenHeight = screenSize.height;

if screenHeight == 480 {

    xCoordinate = 0

    yCoordinate = 74

    width = 320

    height = 361

    var imgNoConnection = UIImage(named: "Noconnectionz.png")
    networkErrorView = UIImageView(image: imgNoConnection)

    }

else if screenHeight == 568 {

    xCoordinate = 0

    yCoordinate = 74

    width = 320

    height = 443

    var imgNoConnection = UIImage(named: "Noconnection@2x.png")
    networkErrorView = UIImageView(image: imgNoConnection)

    }

    return networkErrorView

}

}

这是我在 Objective C 中调用它的地方

Swift *connectivity = [[Swift alloc]init];
bool swiftConnected = [connectivity reachability];

if (!swiftConnected)  {
    NetworkErrorView *networkErrorView = [[NetworkErrorView alloc]init];
    [networkErrorView renderAlertView];
     UIView *subView = [networkErrorView render];
    [super.view addSubview: subView];
    [super.view addSubview:[networkErrorView renderReTryButton]];

    } 
   }

Answer 1

这是你的问题：

[networkErrorView renderAlertView];
 UIView *subView = [networkErrorView render];

您的函数renderAlertView 没有副作用，也就是说，它所做的只是创建一个 UIView 并将其返回给您。但是即使它没有副作用，你仍然在调用它而不将它分配给某个东西。

我不太确定 render 做了什么（请向我们展示它的代码！），但我的猜测是它不会返回任何内容，它只是呈现 networkErrorView，但您将其分配为UIView。所以，我想你想要更像这样的东西：

UIView *subView = [networkErrorView renderAlertView];
[subView render];