在swiftui中按钮的触摸动作播放音频

Posted 2023-02-24

【中文标题】在swiftui中按钮的触摸动作播放音频

【英文标题】：Play audio on touch down action of button in swiftui

【发布时间】：2020-08-09 06:00:57

【问题描述】：

我想在按下按钮时播放音频（一旦单击它）而不是 SwiftUI 中的触摸释放。我该如何实现？

我的代码如下所示：

struct PressedButtonStyle: ButtonStyle 
    let touchDown: () -> ()
    func makeBody(configuration: Self.Configuration) -> some View 
        configuration.label
            .foregroundColor(configuration.isPressed ? Color.gray : Color.blue)
            .background(configuration.isPressed ? self.handlePressed() : Color.clear)
    

    private func handlePressed() -> Color 
        touchDown()
        return Color.clear
    

 

struct DemoPressedButton: View 
    @State var audioPlayer: AVAudioPlayer!

    var body: some View 
        Button("Demo") 
            print(">> tap up")
        
        .buttonStyle(PressedButtonStyle 
            print(">> tap down")
            let sound = Bundle.main.path(forResource: "filename", ofType: "wav")
            self.audioPlayer = try! AVAudioPlayer(contentsOf: URL(fileURLWithPath: sound!)) // receives warning about changing state while updating view
            self.audioPlayer.play() // breaks 
        )
    

调用 self.audioPlayer.play() 时代码中断。 自定义着陆代码来自此链接：SwiftUI button action as soon as button is clicked not on click release

【参考方案1】：

这是一个可能的方法的演示。使用 Xcode 11.4 / ios 13.4 测试

注意：你应该在它播放时保持对AVAudioPlayer的引用并更好地跟踪它的状态，所以这更适合在一些帮助类（比如视图模型）中做

class PlayViewModel 
    private var audioPlayer: AVAudioPlayer!
    func play() 
        let sound = Bundle.main.path(forResource: "filename", ofType: "wav")
        self.audioPlayer = try! AVAudioPlayer(contentsOf: URL(fileURLWithPath: sound!))
        self.audioPlayer.play()
    


struct DemoPressedButton: View 
    let vm = PlayViewModel()

    var body: some View 
        Button("Demo") 
            print(">> tap up")
        
        .buttonStyle(PressedButtonStyle 
            print(">> tap down")
            self.vm.play()
        )
    

【讨论】：

看起来有点老套，makeBody 的 ButtonStyle 应该返回静态的东西。预计将在.on... 方法中执行操作。我会谨慎使用这个解决方案。