Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
1.9k views
in Technique[技术] by (71.8m points)

swift - Dynamically hiding view in SwiftUI

I'm trying to conditionally hide a DatePicker in SwiftUI. However, I'm having any issue with mismatched types:

var datePicker = DatePicker($datePickerDate)
if self.showDatePicker {
    datePicker = datePicker.hidden()
}

In this case, datePicker is a DatePicker<EmptyView> type but datePicker.hidden() is a _ModifiedContent<DatePicker<EmptyView>, _HiddenModifier>. So I cannot assign datePicker.hidden() to datePicker. I've tried variations of this and can't seem to find a way that works. Any ideas?

UPDATE

You can unwrap the _ModifiedContent type to get the underlying type using it's content property. However, this doesn't solve the underlying issue. The content property appears to just be the original, unmodified date picker.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

The simplest and most common way to hide a view is like the following:

struct ContentView: View {
    @State private var showText = true

    var body: some View {
        VStack {
            Button("Toggle text") {
                showText.toggle()
            }

            if showText {
                Text("Hello World!")
            }
        }
    }
}

This removes the Text view from the hierarchy when showText equals false. If you wish to have an option to preserve the space or want it as a modifier, see below.


I created an extension, so you can use a modifier, like so to hide the view:

Text("Hello World!")
    .isHidden(true)

Or for complete removal:

Text("Label")
    .isHidden(true, remove: true)

The extension below is also available on GitHub here if you want to use Swift Packages: GeorgeElsham/HidingViews.


Here is the code to create the View modifier:

I recommend you use this code in its own file (remember to import SwiftUI):

extension View {
    /// Hide or show the view based on a boolean value.
    ///
    /// Example for visibility:
    ///
    ///     Text("Label")
    ///         .isHidden(true)
    ///
    /// Example for complete removal:
    ///
    ///     Text("Label")
    ///         .isHidden(true, remove: true)
    ///
    /// - Parameters:
    ///   - hidden: Set to `false` to show the view. Set to `true` to hide the view.
    ///   - remove: Boolean value indicating whether or not to remove the view.
    @ViewBuilder func isHidden(_ hidden: Bool, remove: Bool = false) -> some View {
        if hidden {
            if !remove {
                self.hidden()
            }
        } else {
            self
        }
    }
}

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...