UIAlertController 操作 sheet 中的 UIPickerView 未显示任何数据

Question

我正在尝试以编程方式创建 UIPickerView 并在操作中显示它的行 sheet。但是，似乎没有任何效果。这是类似的非工作代码的简化示例：

import UIKit

class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {

    let array = ["one","two","three","four","five"]
    var controller: UIAlertController?
    var pickerView = UIPickerView(frame: CGRectMake(0, 15, 304, 0))

    @IBOutlet weak var button: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()

        controller = UIAlertController(title: "Choose Category", message: "\n\n\n\n\n\n\n\n", preferredStyle: .ActionSheet)
        let doneAction = UIAlertAction(title: "Done", style: .Default, handler: nil)
        controller!.addAction(doneAction)

        pickerView.delegate = self
        pickerView.dataSource = self
    }

   @IBAction func buttonPressed(sender: AnyObject) {
        controller!.view.addSubview(self.pickerView)
        self.presentViewController(controller!, animated: true, completion: nil)
    }

    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
        return 1
    }

    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return array.count
    }

    func pickerView(pickerView: UIPickerView, rowHeightForComponent component: Int) -> CGFloat {
        return 50.0
    }

    func pickerView(pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusingView view: UIView?) -> UIView {
        let view = UIView(frame: CGRectMake(0, 0, 100, 70))

        let label = UILabel(frame: CGRectMake(50, 5, 100, 60))
        label.text = array[row] as String

        view.insertSubview(label, atIndex: 1)

        return view
    }
}

按下按钮时，这是输出：

如您所见，操作 sheet 未填充数组值。在我升级到 iOS 9 和 Swift 2.0 之前，这一切都正常工作。我已经使用 print 来确保调用了 pickerView 方法，甚至使用 print 来检查 label 和 view 的值，它们就在那里。任何人都可以指导我的方向或解释导致它不显示的原因吗？

另外：另一个奇怪的事情是如何调用这些方法。如果我按一次按钮，这是发生的每个方法调用的顺序：

numberOfComponentsInPickerView:
numberOfComponentsInPickerView:
rowHeightForComponent:
rowHeightForComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfComponentsInPickerView:
numberOfRowsInComponent:
viewForRow:
viewForRow:
numberOfComponentsInPickerView:
rowHeightForComponent:
rowHeightForComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
numberOfRowsInComponent:
viewForRow:
viewForRow:
viewForRow:
viewForRow:
viewForRow:

Answer 1

您不应该修改 UIAlertController 的视图层次结构。即使您可以让它以这种方式工作，您也有可能在更新时随时冒着 Apple 破坏它的风险，并且您必须不断寻找新的解决方法才能使其工作。您可能需要考虑将选择器放入视图控制器中并将其呈现为 UIModalPresentationPopover。如果您将它与响应器子类一起使用，例如文本字段或您制作的自定义子类，您还可以使用选择器制作一个看起来像动作 sheet 的视图，并将其设置为 inputView响应者。

UIAlertController 操作 sheet 中的 UIPickerView 未显示任何数据

UIPickerView within UIAlertController action sheet is not displaying any data

ios

swift

uipickerview

uialertcontroller