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iOS

Posted by Akira Nagano
Akira Nagano
Courses Plus Student 1,481 Points

Random Color in FunFacts app

Hi,

I was just going through the fun facts app. I was trying to be creative but it didn't work for me. I changed the ColorModel code to the following hoping that it would generate a random color:

import UIKit

struct ColorModel {

    func randomColor() -> UIColor {
        let randomRed = CGFloat(Float(arc4random_uniform(255)))
        let randomGreen = CGFloat(Float(arc4random_uniform(255)))
        let randomBlue = CGFloat(Float(arc4random_uniform(255)))

        return UIColor(red: randomRed/255.0, green: randomGreen/255.0, blue: randomBlue/255.0, alpha: 1.0)
    }
}

The concept works on playground but when implementing into the FunFacts app, the app crash miserably,

Any suggestion?

Thanks,

Akira

2 Answers

Michael Hulet
Michael Hulet
47,913 Points

When I'm trying to make a random color in Swift, this is usually how I do it:

func randomColor() -> UIColor{
    func randomNumber() -> CGFloat{
        return CGFloat(drand48())
    }
    return UIColor(red: randomNumber(), green: randomNumber(), blue: randomNumber(), alpha: 1)
}

I use the drand48 function, which produces a Double between 0 and 1. The UIColor constructor is looking for multiple CGFloats between 0 and 1, so I just embed a small function called randomNumber that generates a random CGFloat between 0 and 1 inside of my main randomColor function, so I can reuse randomNumber inside of randomColor. Then, I just call randomNumber() for every argument of the UIColor constructor, and a random color is made

Perhaps a better, more object-oriented approach to this would be to split it up into extensions on both CGFloat and UIColor, like this:

extension CGFloat{
    static func random() -> CGFloat{
        return CGFloat(drand48())
    }
}

extension UIColor{
    static func random() -> UIColor{
        return UIColor(red: CGFloat.random(), green: CGFloat.random(), blue: CGFloat.random(), alpha: 1)
    }
}

This does exactly the same thing as the first example, but now you can call it in a simple, easy to find, and predictable line:

UIColor.random()
Akira Nagano
PLUS
Akira Nagano
Courses Plus Student 1,481 Points
Akira Nagano
Akira Nagano
Courses Plus Student 1,481 Points

Awesome, thank you very much for your help :D Will try that out!!