[英]Displaying a Sheet from multiple options in swiftUI
iOS14的后续问题引入 @State 绑定错误
我正在显示来自多个选项的模式表,具体取决于按下的按钮。 但是,现在在 iOS14 中,当工作表显示时,由于 selectedSpeaker/selectedMicrophone/selectedAmp 为零,我收到了一个致命错误。 我正在尝试更改为.sheet(item:, content:)
但我看不到如何实现枚举,然后传入适当的选定对象。 这是我之前做的:
enum ActiveSheet {
case speakerDetails, micDetails, ampDetails, settings
}
struct FavoritesView: View {
@State private var selectedSpeaker: Speaker?
@State private var selectedMicrophone: Microphone?
@State private var selectedAmp: Amplifier?
@State private var showingSheet = false
@State private var activeSheet: ActiveSheet = .settings
var body: some View {
List {
Button(action: {
self.activeSheet = .settings
self.showingSheet = true
}, label: { Text("Settings")})
Button(action: {
self.activeSheet = .micDetails
self.selectedMicrophone = microphones[0]
self.showingSheet = true
}, label: { Text("Mic 1")})
Button(action: {
self.activeSheet = .micDetails
self.selectedMicrophone = microphones[1]
self.showingSheet = true
}, label: { Text("Mic 2")})
Button(action: {
self.activeSheet = .speakerDetails
self.showingSheet = true
self.selectedSpeaker = speakers[0]
}, label: { Text("Speaker 1")})
Button(action: {
self.activeSheet = .speakerDetails
self.showingSheet = true
self.selectedSpeaker = speakers[1]
}, label: { Text("Speaker 2")})
//and so on for activeSheet = .ampDetails in the same way.
}
.sheet(isPresented: self.$showingSheet) {
if self.activeSheet == .speakerDetails {
SpeakerDetailView(speaker: self.selectedSpeaker!)
}
else if self.activeSheet == .micDetails {
MicDetailView(microphone: self.selectedMicrophone!)
}
else if self.activeSheet == .ampDetails {
AmpDetailView(amp: self.selectedAmp!)
} else if self.activeSheet == .settings {
SettingsView(showSheet: self.$showingSheet))
}
}
}
}
}
这是您的问题的另一种方法,它使用sheet(item:content:)
struct ContentView: View {
@State private var selectedSpeaker: Speaker?
@State private var selectedMicrophone: Microphone?
@State private var selectedAmp: Amplifier?
@State private var showSettingsSheet = false
var body: some View {
List {
settingsSection
microphonesSection
// more sections
}
}
var settingsSection: some View {
Button(action: {
self.showSettingsSheet = true
}) {
Text("Settings")
}
.sheet(isPresented: self.$showSettingsSheet) {
SettingsView()
}
}
@ViewBuilder
var microphonesSection: some View {
Button(action: {
self.selectedMicrophone = microphones[0]
}) {
Text("Mic 1")
}
Button(action: {
self.selectedMicrophone = microphones[1]
}) {
Text("Mic 2")
}
.sheet(item: self.$selectedMicrophone) {
MicDetailView(microphone: $0)
}
}
}
这样你也不需要enum ActiveSheet
。
您始终可以使用@Environment(\\.presentationMode)
关闭工作表,无需将变量传递给工作表(如SettingsView(showSheet: self.$showingSheet)
):
struct SettingsView: View {
@Environment(\.presentationMode) private var presentationMode
var body: some View {
Text("SettingsView")
.onTapGesture {
presentationMode.wrappedValue.dismiss()
}
}
}
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