如何使用Swift关闭ios中的viewController

Question

I have a viewController which contains only an imageview. I want to present it whenever there is a loading in the application like fetching data from a webservice. So I have created a function in my loaderViewController as

func showLoading(viewController:UIViewController) {
    viewController.presentViewController(LoadingViewController(), animated: false, completion: nil)
}

This is working as expected, when I call this function when desired like below

var loader = LoadingViewController()
loader.showLoading(self)

It show me the viewController with image.

But Now want to dismiss this viewController when desired but I am not able to do so, This is what I have tried so far, I created another function in my LoaderViewController as

func dismissLoader() {
    let load = LoadingViewController()
    load.dismissViewControllerAnimated(true) {
        print("Dismissing Loader view Controller")
    }
}

But its not working and the viewController is not disappering from the screen.

Please guide me

Answer 1

You don't have to create a new instance of your loader and call dismissViewControllerAnimated(_:Bool) on it.

Just call

self.dismissViewControllerAnimated(true)

on your viewController

So, your function will be

func dismissLoader() {

    dismissViewControllerAnimated(true) {
        print("Dismissing Loader view Controller")
    }
}

Answer 2

在Swift 3中，您可以执行以下操作。

self.dismiss(animated: true)

Answer 3

不要每次都let load = YASLoadingViewController() ，你创建不同的控制器做一次，然后只使用load来解雇或呈现

Answer 4

self.dismissViewControllerAnimated(false, completion: nil)

Answer 5

Your code has many flaws. The way you trying to achieve this is not a good practice. However ,If you want a quick fix, and just want to modify your existing method do this,

func dismissLoader() {
    self.dismissViewControllerAnimated(true) 
    print("Dismissing Loader view Controller")
}

And when you're presenting a new LoadingViewController , keep a reference to it, so you can call above method.

Anyways, above code should work even without you holding a reference, since iOS delegate this method back to it's parent ViewController of it's hierarchy, if there's no presented ViewController available on the called ViewController.

Answer 6

You have to store a link for LoadingViewController in parent view controller:

var loader: LoadingViewController?

func showLoadingIn(viewController: UIViewController) {
   loader = LoadingViewController() // create new instance before presentation
   viewController.presentViewController(loader!, animated: false, completion: nil)
}

func dismissLoader() {
    loader?.dismissViewControllerAnimated(true) {
        print("Dismissing Loader view Controller") 
    }
}