如何在 Swift 3 中转换 ++ 或 -- ？ [复制]

Question

我尝试将以下代码转换为 Swift 3 并收到此奇怪错误“无法将 Bool 类型的值转换为预期的参数类型 Int”。当我摆脱“++”时，问题就出现了。我还链接到我想完全转换的堆栈溢出问题。谢谢！这是之前的代码和我尝试转换的代码：

之前的代码

func previousTrack() {
if currentTrack-- < 0 {
    currentTrack = (playerItems.count - 1) < 0 ? 0 : (playerItems.count - 1)
} else {
    currentTrack--
}

playTrack()

}

转换后的代码

@IBAction func didTapPreviousButton(_ sender: UIButton) {
    if currentTrack += 1 < 0 {  // Issue occurs here
        currentTrack = (urlPlayerItems.count - 1) < 0 ? 0 : (urlPlayerItems.count - 1)
    } else {
        currentTrack -= 1
    }

    playTrack()

}

Original question I want to convert to Swift 3

编辑：

@IBAction func didTapPreviousButton(_ sender: UIButton) {
    if (currentTrack - 1) <= 0 {
        currentTrack = (urlPlayerItems.count - 1) < 0 ? 0 : (urlPlayerItems.count - 1)
    } else {
        currentTrack -= 1
    }

    playTrack()

}



@IBAction func didTapNextButton(_ sender: UIButton) {
    if (currentTrack + 1) >= urlPlayerItems.count {
        currentTrack = 0
    } else {
        currentTrack += 1
    }

    playTrack()
}

Answer 1

你想要什么恕我直言

@IBAction func didTapPreviousButton(_ sender: UIButton) {
    currentTrack -= 1
    if currentTrack < 0 {
        currentTrack = (urlPlayerItems.count - 1) < 0 ? 0 : (urlPlayerItems.count - 1)
    }

    playTrack()
}

正确替换 POSTFIX（无用）

@IBAction func didTapPreviousButton(_ sender: UIButton) {
    if currentTrack < 0 {
        currentTrack -= 1
        currentTrack = (urlPlayerItems.count - 1) < 0 ? 0 : (urlPlayerItems.count - 1)
    }

    playTrack()
}