Question

我正在尝试在调用gameOver()时添加警报。 “'警报'初始化程序的结果未使用”。如何初始化我创建的警报？

func gameOver() {
    round = 0
    score = 0
    self.changeTarget()
}

解决方案尝试：

func gameOver() {
    round = 0
    score = 0
    self.changeTarget()
    Alert(title: Text("Game Over"),
    message: Text("Thanks for playing"),
    dismissButton: Alert.Button.default( Text("Play Again")))
}

Answer 1

在SwiftUI框架中，您可以使用多种选项来实现Alert，例如：

func alert<Item>(item: Binding<Item?>, content: (Item) -> Alert) -> some View where Item : Identifiable

以下是使用第一个选项的简单示例：

struct GameOverAlert: View {

    @State private var round = 0
    @State private var score = 0
    @State private var restartGame = false // variable for showing alert

    var body: some View {

        VStack {

            Text("round: \(round)")
            Text("score: \(score)")

            HStack { // used this style just for brevity
                Button(action: { self.score += 1 }) { Text("add score") }
                Button(action: { self.gameOver() }) { Text("over game") }
            }
            Spacer() // only for presenting result

        }
        .alert(isPresented: $restartGame) {
            Alert(title: Text("Your score is \(score)"), dismissButton: .default(Text("Play again")) {
                self.playAgain()
            })
        }


    }

    // described logic here, but it should be in some ViewModel, etc
    private func gameOver() {
        restartGame = true
    }

    private func playAgain() {
        score = 0
        round = 0
    }

}

使用上面的代码，您将实现以下目标：

Answer 2

这最终显示了游戏警告。

.alert(isPresented: $alertIsVisible) { () -> Alert in
    let roundedValue = sliderValueRounded()
    if self.round == 5 {
        return Alert(title: Text("Game Over"), message: Text("Your score was \(score)."), dismissButton: .default(Text("Play Again")) {
        self.startOver()
        })
    } else {
    return Alert(title: Text(alertTitle()), message: Text("The slider's value is \(roundedValue). \n" + "You scored \(pointsForCurrentRound()) points!"), dismissButton: .default(Text("Play Again")){
        self.changeTarget()
        self.round += 1
        })}
}

如何使用SwiftUI在函数内初始化警报？

2 个答案: