Question

我正在尝试在iOS Swift应用中使用ActionSheetStringPicker。我无法弄清楚如何使用完成块或成功操作。这是我的代码：

func pickerDone()
{
    println("Here I am!")
}

override func touchesBegan(touches: NSSet, withEvent event: UIEvent)
{
    var selected = 0
    let done: ActionStringDoneBlock = {(picker: ActionSheetStringPicker!, selectedIndex: NSInteger!, selectedValue : AnyObject!) in
        println(selectedIndex)
    }

    var touch = touches.anyObject() as UITouch

    if touch.view is UILabel
    {
        var picker = ActionSheetStringPicker(title: "Select an attachment", rows: attachmentsList, initialSelection: 0, doneBlock: done, cancelBlock: nil, origin: touch.view)
        picker.showActionSheetPicker()
    }
}

响应触摸的元素是UILabel，名为attachmentLabel，我想根据ActionSheetStringPicker中的选择更改文本。但是，当我进入完成块时，每当我尝试访问传入的三个参数以外的任何内容时，我都会收到EXC_BAD_ACCESS错误。如果我尝试使用pickerDone函数作为成功操作，则仅在调用时调用我定义函数不带任何参数。

我可以为完成块找到的所有示例仅打印出参数的值。我需要一个示例，说明如何将选择器中的信息返回到我的UI。

我试图弄清楚如何捕获变量以便在我的闭包中使用，但是我得到了相同的EXC_BAD_ACCESS错误。我尝试捕获一个本地，但这不起作用：

var selected = 0
let done: ActionStringDoneBlock = {(picker: ActionSheetStringPicker!, selectedIndex: NSInteger!, selectedValue : AnyObject!) in
    selected = selectedIndex
}

然后我尝试捕获自己，但这也不起作用：

let done: ActionStringDoneBlock = {[weak self](picker: ActionSheetStringPicker!, selectedIndex: NSInteger!, selectedValue : AnyObject!) in
    self?.attachmentLabel.text = self?.attachmentsList[selectedIndex]
    return
}

Answer 1

我是ActionSheetPicker的所有者。我没有尝试使用touchesBegan overriding，但它应该是相同的。

我尝试将代码从touchesBegan包装到@IBAction并且它有效（点击完成后打印索引）：

@IBAction func doneBlockInvokeByDoneClicked(sender: UIButton) {
        var selected = 0
        let done: ActionStringDoneBlock = {(picker: ActionSheetStringPicker!, selectedIndex: NSInteger!, selectedValue : AnyObject!) in
            println(selectedIndex)
        }

        var picker = ActionSheetStringPicker(title: "Select an attachment", rows: ["One", "Two", "A lot"], initialSelection: 0, doneBlock: done, cancelBlock: nil, origin: sender.superview!.superview)

        picker.showActionSheetPicker()

    }

以下是从完成块运行函数的示例：

func pickerDone()
{
    println("Here I am!")
}

@IBAction func functionInvokeByDoneCicked(sender: UIButton) {
    var picker = ActionSheetStringPicker(title: "title", rows: ["1","2"], initialSelection: 0, target: self, successAction: "pickerDone", cancelAction: nil, origin: sender.superview!.superview)

    picker.showActionSheetPicker()
}

您的origin参数可能存在问题。检查touch.view是否为主视图。

无法弄清楚如何在Swift中使用闭包

1 个答案: