如何获取在 UIAlertController Swift 的警报中选择的项目的索引

Question

我将使用 UIAlertController 让用户选择一项。 要选择的项目如下：

let arraySelect = ["NewYork", "Washington", "Seoul", "Tokyo", "Peking", "Sidney", ... ]

   let alert = UIAlertController(title: nil, message: nil, preferredStyle: .Alert)

        // Add items in array to Alert
        for var i = 0; i < arraySelect.count; i++ {
            alert.addAction(UIAlertAction(title: arrayBibleVersions[i], style: .Default, handler: {(_) in }))
        }

        // Add cancel button.    
        alert.addAction(UIAlertAction(title: "취소", style: .Cancel, handler: {(_) in }))

        self.presentViewController(alert, animated: false, completion: nil)

当用户触摸一个项目时，我必须获取用户触摸的项目的索引。 但我不知道如何获取索引.. 请帮帮我。

Answer 1

我解决了我的问题如下：

    let arraySelect = ["NewYork", "Washington", "Seoul", "Tokyo", "Peking", "Sidney", ... ]

    let alert = UIAlertController(title: nil, message: nil, preferredStyle: .Alert)

    let closure = { (action: UIAlertAction!) -> Void in
        let index = alert.actions.indexOf(action)

        if index != nil {
            NSLog("Index: \(index!)")
        }
    }

    for var i = 0; i < arrayBibleVersions.count; i++ {
        alert.addAction(UIAlertAction(title: arrayBibleVersions[i][1], style: .Default, handler: closure))
    }

    alert.addAction(UIAlertAction(title: "cancel", style: .Cancel, handler: {(_) in }))

    self.presentViewController(alert, animated: false, completion: nil)

Answer 2

这就是我在 Swift 4 / iOS11 中解决它的方法

projects.forEach { project in
    alertController.addAction(
        UIAlertAction(title: project.name, style: .default, handler: { action in
            if let index = alertController.actions.index(where: { $0 === action }) {
                self.showProject(project: projects[index])
            }
        })
    )
}

Answer 3

我也有同样的问题，找到下面的方法救了我。

但注意如果数组中的项相同，它将返回第一项的索引。

幸运的是，在这种情况下它是有效的，因为我们创建了动作并使用动作进行搜索。

extension Array where Self.Element : Equatable {

    ...

    @inlinable public func index(of element: Element) -> Int?

    ...

}

它在 Swift 4 中工作

    let arraySelect = ["NewYork", "Washington", "Seoul", "Tokyo", "Peking", "Sidney"]

    let alert = UIAlertController(title: nil, message: nil, preferredStyle: .alert)

    // Add items in array to Alert
    for name in arraySelect {
        alert.addAction(UIAlertAction(title: name, style: .default, handler: {(action) in
            // print idx that user selected
            if let idx = alert.actions.index(of: action) {
                print("idx = \(idx)")
            }

        }))
    }

    // Add cancel button.
    alert.addAction(UIAlertAction(title: "취소", style: .cancel, handler: {(_) in }))

    self.present(alert, animated: true, completion: nil)

Answer 4

这很好用：

var arraySelect = ["NewYork", "Washington", "Seoul", "Tokyo", "Peking", "Sidney"]

let alert = UIAlertController(title: nil, message: nil, preferredStyle: .Alert)

let closure = { (action: UIAlertAction!) -> Void in
    let index = alert.actions.indexOf(action)

    if index != nil {
        NSLog("Index: \(index!)")
    }
}

for field in arraySelect {
    alert.addAction(UIAlertAction(title: field, style: .Default, handler: closure))
}

alert.addAction(UIAlertAction(title: "cancel", style: .Cancel, handler: {(_) in }))

self.presentViewController(alert, animated: false, completion: nil)

Answer 5

当用户选择一个动作时执行块。

    // Add cancel button.    
    alert.addAction(UIAlertAction(title: "취소", style: .Cancel, handler: {(_) in 
        //your code
    }))

Answer 6

func FirefoxAhri(){
    let optionMenu = UIAlertController(title: "title", message: "message", preferredStyle: UIAlertControllerStyle.ActionSheet)

    let action1 = UIAlertAction(title: "Yes", style: UIAlertActionStyle.Destructive){
        action -> Void in
        //do stuff on click Yes
    }

    let action2 = UIAlertAction(title: "No", style: UIAlertActionStyle.Destructive){
        action -> Void in
        //do stuff on click No
    }

    let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel) { action -> Void in
        print("Cancel")
        // do nothing if you don't want. alert closes automatically
    }

    optionMenu.addAction(action1)
    optionMenu.addAction(action2)
    optionMenu.addAction(cancelAction)
    self.presentViewController(optionMenu, animated: true, completion: nil)
}