这是 unwind segue的完美情况。

将它放在你的第一个viewController（你想要返回的那个）中：

Put this in your first viewController (the one you want to return to):

@IBAction func backFromVC3(_ segue: UIStoryboardSegue) {
    print("We are back in VC1!")
}

然后在第3个viewController的Storyboard中， control -drag从你的按钮到viewController顶部的退出图标，从弹出窗口中选择 backFromVC3 。

Then in the Storyboard in your 3rd viewController, control-drag from your button to the exit icon at the top of the viewController and choose backFromVC3 from the pop-up.

现在，当用户按下VC3中的按钮时，VC3和VC2将被解雇，你将返回VC1。

Now, when the user presses the button in VC3, both VC3 and VC2 will be dismissed and you will return to VC1.

如果你没有使用Storyboard，你可以解雇viewControllers码。下面是一个按钮处理程序的代码，用于解除两个级别的viewController：

If you are not using Storyboards, you can dismiss the viewControllers with code. Here is code for a button's handler to dismiss two levels of viewController:

func doDismiss(_ sender: UIButton) {
    // Use presentingViewController twice to go back two levels and call
    // dismissViewController to dismiss both viewControllers.
    self.presentingViewController?.presentingViewController?.dismiss(animated: true, completion: nil)
}