My first app does not work! I just want the button to change the color of the screen when clicked.

Question

This is my first attempt sharing code. Any tips on how to do it correctly? I have the button connected to both Outlet and Action.

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var randomWordButton: UIButton! let colorProvider = BackGroundColorProvider()

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

@IBAction func showWord() {
    let randomColor = colorProvider.randomColor()
    view.backgroundColor = randomColor
}

}

// Separate File

import GameKit import UIKit

struct BackGroundColorProvider {

let colors = [
    UIColor(red: 90/255.0, green: 187/255.0, blue: 181/255.0, alpha: 1.0), // teal color
    UIColor(red: 222/255.0, green: 171/255.0, blue: 66/255.0, alpha: 1.0), //yellow color ]

func randomColor() -> UIColor {

let randomNumber = GKRandomSource.sharedRandom().nextInt(upperBound: colors.count)

return colors[randomNumber] } }

Answer 1 · 2017-02-19T20:33:12Z

February 19, 2017 8:33pm

To check the connection, first go to your Main.storyboard. Once there, make sure your Document Outline is open. If you are not sure what part that is, click the small box(hovering your curser over the box reveals it's name) down beside where it says View as: iPhone7(wC hR), to the left of those words. That will open the Document Outline, and it will show the View Controller Scene with a drop down menu, showing your views, buttons, labels and whatever else you have added to the view controller. When I create outlets or actions, I usually control-drag from this area (using the Assistant Editor) to my code. Sometimes when dragging from the item in the view controller, you can accidentally drag from a constraint, instead of the button or label.
Once you have the Document Outline open, highlight the Button, and open the Connections inspector, which is near the top right hand side of Xcode. It looks like a circle with an arrow pointing to the left inside of it. Now you will see if that button, or whatever you have selected in the Document Outline, is connected and what type of action it is connected too. You could just delete the action here, delete the action in your view controller code, and try again and see if that works. In terms of how to create the connection, there are a few different ways(which I won't get into here), I just tend to use the Document Outline and Assistant Editor, as I don't seem to run into problems this way. I have with others(i.e. accidentally dragging from a constraint instead of the actual button). Everyone has there own preference though. I don't know how to do screen-shots, otherwise I would post some of those to make it a bit more clear. If none of this helps, I would have to see the whole project and run it on my end to see what the error could be. You would have to have the project up on github for that though. But, if this is all the code you have so far, and this error keeps happening, maybe just create a new project, with your code like the two files I posted above, and the button in Storyboard. Mine worked just fine. Let me know if you figure it out, and I will do my best to help if I can.

Answer 2 · 2017-02-19T15:25:37Z

February 19, 2017 3:25pm

Hey Martel,

I was able to get this working in Xcode myself, going off the code you shared. My feeling is that your IBOutlet or IBAction is broken. I noticed that you have your function that changes background color called "showWord", which that function has nothing to do with. Did you change the name of your action AFTER you connected it? That would cause problems. Without seeing the whole project though, I can't tell what is causing your error.

Here is what my two files look like, and I just have one button hooked up in Storyboard:

import UIKit

class ViewController: UIViewController {

    let colorChanger = BackgroundColorProvider()

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @IBAction func changeColor(_ sender: Any) {
        let newColor = colorChanger.randomColor()
        view.backgroundColor = newColor
    }

}

and the second

import UIKit
import GameKit

struct BackgroundColorProvider {
    let colors = [
        UIColor(red: 90/255.0, green: 187/255.0, blue: 181/255.0, alpha: 1.0), // teal color
        UIColor(red: 222/255.0, green: 171/255.0, blue: 66/255.0, alpha: 1.0), //yellow color
    ]

    func randomColor() -> UIColor {
        let randomNumber = GKRandomSource.sharedRandom().nextInt(upperBound: colors.count)
        return colors[randomNumber]
    }
}

In the Main.storyboard file, select the button and checkout the Connections inspector to make sure it is connected right.

Hope this helps

Dan

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Martel Storm

Martel Storm

My first app does not work! I just want the button to change the color of the screen when clicked.

Martel Storm

Martel Storm

2 Answers

Dan Lindsay

Dan Lindsay

Martel Storm

Martel Storm

Dan Lindsay

Dan Lindsay

Martel Storm

Martel Storm