如果要将约束作为UIPickerView的子视图添加，则需要向UIToolBar添加约束吗？

Question

我正在尝试以编程方式向我的UIPickerView添加一个简单的“完成”按钮，而不使用情节提要。

[当我尝试将toolBar添加为UIPickerView的子视图时，工具栏甚至不显示，并且出现一些与约束相关的错误。

关于如何将按钮添加到PickerView的任何想法？

这是我的代码段：

var timerImage = UIButton()
var timer = Timer()
var timerDisplayed = 0
let image1 = UIImage(named: "stopwatch")
let timePicker = UIPickerView()
let timeSelect : [String] = ["300","240","180","120","90","60","45","30","15"]

let toolBar = UIToolbar()
let doneButton = UIBarButtonItem(title: "Done", style: .plain, target: self, action: #selector(ThirdViewController.dismissKeyboard))

func pickerViewConstraints(){
    timePicker.anchor(top: nil, leading: view.safeAreaLayoutGuide.leadingAnchor, bottom: view.safeAreaLayoutGuide.bottomAnchor, trailing: view.safeAreaLayoutGuide.trailingAnchor)
}

@objc func timeClock(){
    toolBar.setItems([doneButton], animated: true)
    toolBar.sizeToFit()
    toolBar.isTranslucent = false
    toolBar.isUserInteractionEnabled = true
    toolBar.barStyle = .default

    view.addSubview(timePicker)
    timePicker.addSubview(toolBar)
    pickerViewConstraints()
    timePicker.backgroundColor = .white

    DispatchQueue.main.async {
        self.timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(self.Action), userInfo: nil, repeats: true)
        self.timerImage.setImage(nil, for: .normal)
    }
}

Answer 1

不，您不需要添加约束。它可以像：

let space = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
let doneButton = UIBarButtonItem(title: buttonTitle, style: .done, target: self, action: #selector(doneButtonAction))
let cancelButton = UIBarButtonItem(title: cancelTitle, style: .plain, target: self, action: #selector(cancelButtonAction))
let barAccessory = UIToolbar(frame: CGRect(x: 0, y: 0, width: view.frame.width, height: 44))
barAccessory.barStyle = .default
barAccessory.isTranslucent = true
barAccessory.barTintColor = .blue
barAccessory.setItems([cancelButton, space, doneButton], animated: false)
picker.addSubview(barAccessory)
self.view.bringSubviewToFront(picker)

希望有帮助...

Answer 2

看来这只是几个小问题。这是我之前做过的方法：

    override func viewDidLoad() {
    super.viewDidLoad()

    createToolbar()
}
    // Toolbar for "done"
    func createToolbar() {
        let toolBar = UIToolbar()
        toolBar.sizeToFit()


        let doneButton = UIBarButtonItem(title: "Done", style: .plain, target: self, action: #selector(PageOneViewController.dismissKeyboard))

        toolBar.setItems([doneButton], animated: false)
        toolBar.isUserInteractionEnabled = true

        // Makes toolbar apply to text fields
        educationText.inputAccessoryView = toolBar
        politicalText.inputAccessoryView = toolBar
        drinkingText.inputAccessoryView = toolBar
        heightText.inputAccessoryView = toolBar
        schoolInput.inputAccessoryView = toolBar
    }

@objc func dismissKeyboard() {
        view.endEditing(true)
    }

似乎您没有从技术上“调用”工具栏/完成按钮，除非我只是没有看到代码的那部分。另外，我还在函数内部嵌套了“完成”代码。

[如果您正在使用文本字段，那么您应该能够遵循“ educationText.inputAccessoryView = toolBar”格式，将上述所有代码应用于每个文本字段（教育，政治，饮酒等）。我希望这有帮助！祝你好运。

Answer 3

您需要为选择器视图设置UIPickerViewDelegate类型的委托。在此委托中，实现委托方法pickerView：viewForRow：forComponent：reusingView

为您的选择器项目提供自定义视图。

对于您提供的自定义视图，可以根据需要进行设计，包括添加按钮。