如何在 SwiftUI 中的 class 內的計時器中運行來自視圖的操作？

Question

我想在我的 class 中運行一個Void動作，這個動作來自我的視圖，目前它是第一次運行，然后拋出EXC_BAD_ACCESS錯誤。 我知道我在兩者之間遺漏了一些東西，但找不到它，需要幫助。

---

struct ContentView: View {
    
    @StateObject var customTimer: CustomTimer = CustomTimer()

    var body: some View {
        
        VStack(spacing: 30.0) {
            
            Button("start timer") {
                
                customTimer.timerFunction(action: { print("Hello") })
                customTimer.startTimer(timeInterval: 1.0) //<<: Thread 1: EXC_BAD_ACCESS (code=1, address=0x4d555460)
     
            }
            
            Button("stop timer") {
                
                customTimer.stopTimer()
     
            }
            
        }
        .font(Font.body.bold())

    }

}

---

class CustomTimer: ObservableObject {
    
    private var timer: Timer = Timer()

    func startTimer(timeInterval: Double) {

        timer = Timer.scheduledTimer(timeInterval: timeInterval, target: self, selector: #selector(timerFunction), userInfo: nil, repeats: true)
        RunLoop.current.add(timer, forMode: .common)
        timer.tolerance = 0.0

    }
    
    func stopTimer() { timer.invalidate() }

    @objc func timerFunction(action: () -> Void) { action() }

}

Answer 1

我發現了問題，我應該為此定義一個閉包，如下所示：

var action: () -> Void = {}

如果您發現有任何改進，請告訴我，謝謝

---

struct ContentView: View {
    
    @StateObject var customTimer: CustomTimer = CustomTimer()

    var body: some View {
        
        VStack(spacing: 30.0) {
            
            Button("start timer") {

                customTimer.action = { print("Hello") }
                customTimer.startTimer(timeInterval: 1.0)
     
            }
            
            Button("stop timer") {
                
                customTimer.stopTimer()
     
            }
            
        }
        .font(Font.body.bold())

    }

}

---

class CustomTimer: ObservableObject {
    
    private var timer: Timer = Timer()
    
    var action: () -> Void = {}

    func startTimer(timeInterval: Double) {

        timer = Timer.scheduledTimer(timeInterval: timeInterval, target: self, selector: #selector(timerFunction), userInfo: nil, repeats: true)
        RunLoop.current.add(timer, forMode: .common)
        timer.tolerance = 0.0

    }
    
    func stopTimer() { timer.invalidate() }

    @objc private func timerFunction() { action() }

}