SwiftUI - 如何检查是否启用了暗模式? [英] SwiftUI - How do I check to see if dark mode is enabled?

问题描述

如何检查设备上的暗模式是否已启用.我想从视图中检查这个并有条件地显示或隐藏阴影.

How do I check to see if dark mode on the device is enabled. I want to check this from within a view and conditionally show or hide a shadow.

我以为我可以从环境中获取 colorScheme，但我想我错过了一些东西.

I thought I could jus get the colorScheme from the environment but I think I'm missing something.

struct FloatingAddButton : View {

    @Environment(\.colorScheme) var colorScheme 

    @Binding var openAddModal: Bool

    var body : some View {
        VStack {
            Spacer()
            HStack() {
                Spacer()
                Button(action: {

                    self.openAddModal = true

                }) {

                    ZStack {
                        Circle()
                            .foregroundColor(Color(RetroTheme.shared.appMainTint))
                            .frame(width: 50, height: 50, alignment: .center)
                        if(self.colorScheme == .light) {
                            .shadow(color: .secondary, radius: 5, x: 0, y: 0)
                        }

                        Image(systemName: "plus")
                            .foregroundColor(Color.white)
                    }

                } // End Button
            }
        }
    }

}

推荐答案

在我的代码中，我有一个简单的 View 扩展，它使代码更具可读性.有了它，我可以有条件地应用修饰符:

In my code, I have a simple View extension, that makes the code a lot more readable. With it, I can apply modifiers conditionally:

.conditionalModifier(self.colorScheme == .light, LightShadow())

完整的实现如下:

extension View {
    // If condition is met, apply modifier, otherwise, leave the view untouched
    public func conditionalModifier<T>(_ condition: Bool, _ modifier: T) -> some View where T: ViewModifier {
        Group {
            if condition {
                self.modifier(modifier)
            } else {
                self
            }
        }
    }
}

struct FloatingAddButton : View {

    @Environment(\.colorScheme) var colorScheme

    @Binding var openAddModal: Bool

    var body : some View {
        VStack {
            Spacer()
            HStack() {
                Spacer()
                Button(action: { self.openAddModal = true }) {

                    ZStack {
                        Circle()
                            .foregroundColor(Color(.red))
                            .frame(width: 50, height: 50, alignment: .center)
                            .conditionalModifier(self.colorScheme == .light, LightShadow())

                        Image(systemName: "plus")
                            .foregroundColor(Color.white)
                    }
                }

            } // End Button

        }
    }
}

struct LightShadow: ViewModifier {
    func body(content: Content) -> some View {
        content.shadow(color: .secondary, radius: 5, x: 0, y: 0)
    }
}

如果您想为 true 和 false 应用不同的修饰符，这是另一个扩展:

If you ever have a case where you want to apply different modifiers for true and false, here's another extension:

extension View {
    // Apply trueModifier if condition is met, or falseModifier if not.
    public func conditionalModifier<M1, M2>(_ condition: Bool, _ trueModifier: M1, _ falseModifier: M2) -> some View where M1: ViewModifier, M2: ViewModifier {
        Group {
            if condition {
                self.modifier(trueModifier)
            } else {
                self.modifier(falseModifier)
            }
        }
    }
}

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