ios - 异步回调中的递归(Swift)

Question

下面是一些代码，它旨在使手机振动(异步)，等待此任务完成，然后立即使其再次振动:

func vibrate() {
    AudioServicesPlayAlertSound(SystemSoundID(kSystemSoundID_Vibrate))
    AudioServicesAddSystemSoundCompletion(SystemSoundID(kSystemSoundID_Vibrate), nil, nil, { (soundId, clientData) -> Void in
        self.vibrate()
    }, nil)
}

Xcode 给出以下错误:

A C function pointer cannot be formed from a closure that captures context

如何从这个异步函数内部递归？

Answer 1

我正在努力寻找您问题的解决方案，我偶然发现了这个线程:https://forums.swift.org/t/a-c-function-pointer-cannot-be-formed-from-a-local-function-that-captures-context-on-swift-package/9388/6

我确实将 vibrate() 方法封装到一个新的结构中，如下所示:

import AudioToolbox
import CoreAudioKit

struct Vibrator {
    static func vibrate() {
        AudioServicesPlayAlertSound(SystemSoundID(kSystemSoundID_Vibrate))
        AudioServicesAddSystemSoundCompletion(SystemSoundID(kSystemSoundID_Vibrate), nil, nil, { (soundId, clientData) in
            Vibrator.vibrate()
        }, nil)
    }
}

当然可以这样调用它:Vibrator.vibrate()。瞧!

希望对您有所帮助!