如何让UIButton弹出菜单初始无选中项？附控件选择咨询

问题原因 #

你设置changesSelectionAsPrimaryAction = true后，系统会自动将UIMenu设为单选模式（等价于添加.singleSelection选项），这种模式下系统会强制选中第一个选项，哪怕你手动把所有UIAction的state设为.off也没用。

下面给出两种可行的完整方案，你可以根据场景选择：

方案一：UIButton + UIMenu（自定义单选逻辑） #

放弃系统自动的单选管理，手动维护选中状态，这样就能实现初始无选中的效果。

完整代码 #

import UIKit

class ViewController: UIViewController {
    // 保存选中的Action，初始为nil表示无选中
    private var selectedGenderAction: UIAction?
    
    private lazy var genderButton: UIButton = {
        let button = UIButton(type: .system)
        // 初始显示提示文本
        button.setTitle("Select Gender".localized, for: .normal)
        button.titleLabel?.font = UIFont.systemFont(ofSize: 16)
        button.frame = CGRect(x: 50, y: 200, width: 300, height: 44)
        // 允许点击弹出菜单
        button.showsMenuAsPrimaryAction = true
        return button
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        view.addSubview(genderButton)
        setupGenderMenu()
    }
    
    private func setupGenderMenu() {
        let genderTitles = ["Male".localized, "Female".localized]
        
        let genderActions = genderTitles.map { title in
            UIAction(title: title, state: .off) { [weak self] action in
                // 取消之前选中项的状态
                self?.selectedGenderAction?.state = .off
                // 设置当前项为选中
                action.state = .on
                self?.selectedGenderAction = action
                // 更新按钮标题为选中项
                self?.genderButton.setTitle(title, for: .normal)
            }
        }
        
        // 创建菜单时不要添加.singleSelection选项，避免系统强制选中第一项
        let menu = UIMenu(children: genderActions)
        genderButton.menu = menu
    }
}

优势 #

• 代码简洁，系统原生交互体验，适配iOS设计规范
• 无需额外处理键盘、选择器的显示逻辑

方案二：UITextField + UIPickerView #

适合需要更自定义样式，或者和表单其他输入控件风格统一的场景。

完整代码 #

import UIKit

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
    // 性别选项
    private let genderOptions = ["Male".localized, "Female".localized]
    // 保存选中的索引，初始为nil表示无选中
    private var selectedGenderIndex: Int?
    
    private lazy var genderTextField: UITextField = {
        let textField = UITextField()
        textField.placeholder = "Select Gender".localized
        textField.borderStyle = .roundedRect
        textField.font = UIFont.systemFont(ofSize: 16)
        textField.frame = CGRect(x: 50, y: 200, width: 300, height: 44)
        // 设置PickerView为输入视图
        textField.inputView = genderPickerView
        // 添加工具栏用于收起键盘
        textField.inputAccessoryView = createToolbar()
        return textField
    }()
    
    private lazy var genderPickerView: UIPickerView = {
        let picker = UIPickerView()
        picker.delegate = self
        picker.dataSource = self
        return picker
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        view.addSubview(genderTextField)
    }
    
    // 创建顶部工具栏
    private func createToolbar() -> UIToolbar {
        let toolbar = UIToolbar(frame: CGRect(x: 0, y: 0, width: view.bounds.width, height: 44))
        toolbar.barStyle = .default
        
        let doneButton = UIBarButtonItem(title: "Done".localized, style: .done, target: self, action: #selector(doneButtonTapped))
        let flexibleSpace = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
        
        toolbar.items = [flexibleSpace, doneButton]
        return toolbar
    }
    
    // MARK: - PickerView 代理方法
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }
    
    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return genderOptions.count
    }
    
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        return genderOptions[row]
    }
    
    func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
        selectedGenderIndex = row
        genderTextField.text = genderOptions[row]
    }
    
    // MARK: - 工具栏按钮点击事件
    @objc private func doneButtonTapped() {
        genderTextField.resignFirstResponder()
        // 如果用户未选择任何项，清空文本，保留placeholder
        if selectedGenderIndex == nil {
            genderTextField.text = nil
        }
    }
}

优势 #

• 高度可自定义：可以修改PickerView的行样式、添加图标，或者调整TextField的外观
• 适合表单场景，和其他输入控件风格统一

方案选择建议 #

• 如果只是需要简单的单选选择，优先用UIButton+UIMenu，开发效率更高
• 如果需要自定义界面或者融入表单，选择UITextField+UIPickerView更合适

内容的提问来源于stack exchange，提问作者Burhanuddin Sunelwala