[英]SwiftUI - TabBar Button Change
嗨,我正在学习 SwiftUI,在尝试构建应用程序时遇到了问题。 我的问题是如何制作一个在活动时更改systemImage
的选项卡栏(当主页按钮处于活动状态时,它显示“home.fill”,当用户按下搜索按钮时,主页按钮变为“主页”)。
如果您看到我可以在下面的代码中做出任何改进,我们也将不胜感激。 谢谢你,祝你有美好的一天,并保持安全。
import SwiftUI
struct ContentView: View {
@State private var fullScreenCover = false
init() {
UITabBar.appearance().isTranslucent = false
}
var body: some View {
VStack {
ForEach(0..<6) { num in
Spacer()
}
HStack {
Spacer()
Button(action: {}, label: {
Image(systemName: "message")
.font(.system(size: 20))
})
.padding(.horizontal, 15)
}
.foregroundColor(Color("Reverse"))
.padding(.vertical, 8)
TabView {
Main_Home()
.tabItem {
Image(systemName: "house")
.font(.system(size: 30))
}
Main_Search()
.tabItem {
Image(systemName: "magnifyingglass")
.font(.system(size: 30))
}
Main_AddContent()
.tabItem {
Image(systemName: "plus.viewfinder")
.font(.system(size: 30))
}
Main_Message()
.tabItem {
Image(systemName: "pencil.circle.fill")
.font(.system(size: 30))
}
Main_Profile()
.tabItem {
Image(systemName: "person.crop.circle")
.font(.system(size: 30))
}
}
.accentColor(Color("Reverse"))
}
.background(Color("Normal"))
.edgesIgnoringSafeArea(.all)
}
}
这是一个自定义ViewModifier
,可用于添加选项卡项:
public struct TabViewItem<SelectionValue>: ViewModifier where SelectionValue: Hashable {
@Binding private var selectedIndex: SelectionValue
private let index: SelectionValue
private let text: String
private let imageName: String
public init(selectedIndex: Binding<SelectionValue>, index: SelectionValue, text: String, imageName: String) {
self._selectedIndex = selectedIndex
self.index = index
self.text = text
self.imageName = imageName
}
public func body(content: Content) -> some View {
content
.tabItem {
image
Text(text)
}
.tag(index)
}
private var image: some View {
guard selectedIndex == index else {
return Image(systemName: imageName)
}
let imageName = self.imageName + ".fill"
if let uiImage = UIImage(systemName: imageName) {
return Image(uiImage: uiImage)
}
return Image(systemName: self.imageName)
}
}
public extension View {
func tabItem<Selection>(
_ text: String,
imageName: String,
index: Selection,
selection: Binding<Selection>
) -> some View where Selection: Hashable {
modifier(TabViewItem(selectedIndex: selection, index: index, text: text, imageName: imageName))
}
}
然后,创建TabView
就更简单了:
struct ContentView: View {
@State private var selectedTab = 3
var body: some View {
TabView(selection: $selectedTab) {
Text("Main_Home")
.tabItem("Home", imageName: "house", index: 1, selection: $selectedTab)
Text("Main_Search")
.tabItem("Search", imageName: "magnifyingglass", index: 2, selection: $selectedTab)
Text("Main_AddContent")
.tabItem("AddContent", imageName: "plus.viewfinder", index: 3, selection: $selectedTab)
Text("Main_Message")
.tabItem("Message", imageName: "pencil.circle", index: 4, selection: $selectedTab)
Text("Main_Profile")
.tabItem("Profile", imageName: "person.crop.circle", index: 5, selection: $selectedTab)
}
}
}
注意:上述实现是出于通用目的 - 如果您不需要某些部分(如选项卡中的text
),只需将其删除或使其成为可选。
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