提前感谢您提供的任何建议。我有一个在 SwiftUI 中构建的自定义下拉菜单:
struct PhoneTypeDropdown: View {
let phoneTypes:[PhoneType] = [.Cell, .Work, .Landline]
@State var isExpanded: Bool
var body : some View {
VStack (spacing: 0) {
HStack {
Text("select type").font(.footnote)
Spacer()
Image(systemName: Constants.Design.Image.IconString.ChevronDown)
.resizable()
.frame(width: Constants.Design.Measurement.DropDownIconWidth,
height: Constants.Design.Measurement.DropDownIconHeight)
}
.padding(Constants.Design.Measurement.PadMin)
.background(Constants.Design.Colors.LightGrey)
.cornerRadius(Constants.Design.Measurement.CornerRadius)
.onTapGesture {
self.isExpanded.toggle()
}
if isExpanded {
VStack (spacing: 0){
ForEach(0 ..< phoneTypes.count) { i in
Button(self.phoneTypes[i].description, action: {
print("button tapped")
self.isExpanded.toggle()
})
.buttonStyle(DropDownButtonStyle())
if i != self.phoneTypes.count - 1 {
Divider()
.padding(.vertical, 0)
.padding(.horizontal, Constants.Design.Measurement.Pad)
.foregroundColor(Constants.Design.Colors.DarkGrey)
}
}
}.background(Constants.Design.Colors.LightGrey)
.cornerRadius(Constants.Design.Measurement.CornerRadiusMin)
.padding(.top, Constants.Design.Measurement.PadMin)
}
}.frame(width: Constants.Design.Measurement.PhoneTypeFieldWidth)
.cornerRadius(Constants.Design.Measurement.CornerRadius)
}
}
当我在我看来使用它时,我曾计划将它用作这样的叠加层:
VStack(spacing: 0) {
ProfileField(text: phone1,
label: Constants.Content.PrimaryPhone,
position: .Justified)
.overlay(
PhoneTypeDropdown(isExpanded: expandDropdown1)
.padding(.top, 32) //FIXME: Fix this hard-coded value.
.padding(.trailing, Constants.Design.Measurement.PadMax),
alignment: .topTrailing
)
}
然而,虽然上面的代码会在点击并展开下拉框时触发,但点击下拉框内的任何Button
对象都不会执行任何操作。然后我尝试使用ZStack
这样的实现下拉框:
ZStack(alignment: .topTrailing) {
ProfileField(text: phone1,
label: Constants.Content.PrimaryPhone,
position: .Justified)
PhoneTypeDropdown(isExpanded: expandDropdown1)
.padding(.top, 32) //FIXME: Fix this hard-coded value.
.padding(.trailing, Constants.Design.Measurement.PadMax)
}
下拉框工作得很好,可以按预期展开和折叠。但是,现在,当它展开时,它会向下推表单的其余部分,而不是根据需要放置在表单的顶部。
ZStack
那么我的问题是:当在 a 中使用下拉对象而不是将其合并到overlay
a 中的视图中时,什么会导致我的按钮操作正确触发VStack
?