Switching Views Programmatically in Swift

Question

I am trying to switch to the second view by pressing the "feeling lucky" button. When I try out my simulator and press it, it just goes to a black screen. How could I fix this?

@IBAction func FeelingLuckyPress(sender: UIButton) {

    let secondViewController:SecondViewController = SecondViewController()

    self.presentViewController(secondViewController, animated: true, completion: nil)
}

Bethlehem

Where is SecondViewController supposed to get its view from? To put it another way, what you have done so that this view should not be a black screen? Explain. Describe. – Corkhill

Here are the ways a view controller gets its view. If you don't use one of them, the view controller's view is empty and black: apeth.com/iOSBook/ch19.html#_view_controller_and_view_creation – Corkhill

Answer 1

You can add a segue between the two scenes in your storyboard by control dragging from the view controller icon at the top of the first scene to the second scene:

You can then select that segue and give it a unique storyboard identifier, and then you can just perform the segue using that identifier:

performSegue(withIdentifier: "SegueToSecond", sender: self)

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Alternatively, you can do something like:

guard let controller = storyboard?.instantiateViewController(withIdentifier: "Second") as? SecondViewController else {
    return
}
present(controller, animated: true) // or `show(controller, sender: self)`

where “Second” is a storyboard identifier I specified for that destination scene in Interface Builder.

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By the way, there are alternatives if you are creating your destination scene programmatically or using NIBs, but storyboards are more common, so I focused on that in my examples above.

Bron