如何通过代码触发SwiftUI DatePicker弹窗？

我有一个SwiftUI的DatePicker，正常点击日期文本（比如“Jan 11 2023”）时会弹出选择器。现在想实现：点击界面上其他按钮时，自动弹出这个DatePicker的选择器，请问有没有可行的实现方式？

我使用的DatePicker代码如下：

DatePicker("Jump to", selection: $date, in: dateRange, displayedComponents: [.date]) 

我测试了@rob mayoff的解决方案，但未成功。在Xcode 14.2、iPhone 14 iOS 16.2模拟器及真机上测试时，triggerDatePickerPopover()确实被调用，但始终执行不到button.accessibilityActivate()这一步。

测试代码如下：

import SwiftUI

struct ContentView: View {
  @State var date: Date = .now
  let dateRange: ClosedRange<Date> = Date(timeIntervalSinceNow: -864000) ... Date(timeIntervalSinceNow: 864000)

  var pickerId: String { "picker" }

  var body: some View {
    VStack {
      DatePicker(
        "Jump to",
        selection: $date,
        in: dateRange,
        displayedComponents: [.date]
      )
      .accessibilityIdentifier(pickerId)

      Button("Clicky") {
        triggerDatePickerPopover()
          print("Clicky Triggered")
      }
    }
    .padding()
  }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

extension NSObject {
  func accessibilityDescendant(passing test: (Any) -> Bool) -> Any? {

    if test(self) { return self }

    for child in accessibilityElements ?? [] {
      if test(child) { return child }
      if let child = child as? NSObject, let answer = child.accessibilityDescendant(passing: test) {
        return answer
      }
    }

    for subview in (self as? UIView)?.subviews ?? [] {
      if test(subview) { return subview }
      if let answer = subview.accessibilityDescendant(passing: test) {
        return answer
      }
    }

    return nil
  }
}


extension NSObject {
  func accessibilityDescendant(identifiedAs id: String) -> Any? {
    return accessibilityDescendant {
      // For reasons unknown, I cannot cast a UIView to a UIAccessibilityIdentification at runtime.
      return ($0 as? UIView)?.accessibilityIdentifier == id
      || ($0 as? UIAccessibilityIdentification)?.accessibilityIdentifier == id
    }
  }
    
    func buttonAccessibilityDescendant() -> Any? {
       return accessibilityDescendant { ($0 as? NSObject)?.accessibilityTraits == .button }
     }
}

extension ContentView {
  func triggerDatePickerPopover() {
    if
      let scene = UIApplication.shared.connectedScenes.first as? UIWindowScene,
      let window = scene.windows.first,
      let picker = window.accessibilityDescendant(identifiedAs: pickerId) as? NSObject,
      let button = picker.buttonAccessibilityDescendant() as? NSObject
    {
        print("triggerDatePickerPopover")
      button.accessibilityActivate()
    }
  }
}

更新记录 #

• 更新2：按照调试指引操作后发现，即使代码完全一致，检查器中仍缺少accessibility标识符，暂时不清楚原因。
• 更新3：@rob mayoff的解决方案其实非常有效！如果使用时遇到问题，可以稍等片刻，可能是设备或模拟器正在准备无障碍功能导致的延迟。

内容的提问来源于stack exchange，提问作者Legolas Wang