使用 SwiftUI 在条件内显示警报
Display an Alert inside a conditional with SwiftUI
我知道 Alert
可以表示为 Button
的函数,但是 Alert
可以在条件语句中表示吗?如:
struct ContentView: View {
var body: some View {
Text("Hello World!")
}
}
if isValid {
//present alert
let alert = UIAlertController(title: "My Title", message: "This
is my message.", preferredStyle: UIAlertController.Style.alert)
alert.addAction(UIAlertAction(title: "OK", style:
UIAlertAction.Style.default, handler: nil))
self.present(alert, animated: true, completion: nil)
}
有了这个我得到
Value of type 'ContentView' has no member 'present'
我不确定你为什么要使用 UIKit。这是一个示例,说明当某些内容更改标志时如何显示警报。在这种情况下,一个两秒计时器:
import SwiftUI
class MyModel: ObservableObject {
@Published var isValid: Bool = false
init() {
DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(2)) {
self.isValid = true
}
}
}
struct ContentView: View {
@ObservedObject var model: MyModel = MyModel()
var body: some View {
VStack {
Text("Some text")
Text("Some text")
Text("Some text")
Text("Some text")
}.alert(isPresented: $model.isValid, content: {
Alert(title: Text("Title"),
message: Text("Message"),
dismissButton: .default(Text("OK")) { print("do something") })
})
}
}
我知道 Alert
可以表示为 Button
的函数,但是 Alert
可以在条件语句中表示吗?如:
struct ContentView: View {
var body: some View {
Text("Hello World!")
}
}
if isValid {
//present alert
let alert = UIAlertController(title: "My Title", message: "This
is my message.", preferredStyle: UIAlertController.Style.alert)
alert.addAction(UIAlertAction(title: "OK", style:
UIAlertAction.Style.default, handler: nil))
self.present(alert, animated: true, completion: nil)
}
有了这个我得到
Value of type 'ContentView' has no member 'present'
我不确定你为什么要使用 UIKit。这是一个示例,说明当某些内容更改标志时如何显示警报。在这种情况下,一个两秒计时器:
import SwiftUI
class MyModel: ObservableObject {
@Published var isValid: Bool = false
init() {
DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(2)) {
self.isValid = true
}
}
}
struct ContentView: View {
@ObservedObject var model: MyModel = MyModel()
var body: some View {
VStack {
Text("Some text")
Text("Some text")
Text("Some text")
Text("Some text")
}.alert(isPresented: $model.isValid, content: {
Alert(title: Text("Title"),
message: Text("Message"),
dismissButton: .default(Text("OK")) { print("do something") })
})
}
}