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iOS Build a Simple iPhone App with Swift Creating a Data Model Finishing Up Our Model

Michael Henry
Michael Henry
14,601 Points
Posted by Michael Henry
Michael Henry
14,601 Points

Extending random color generation...help please!!!

Hi all,

I am trying to take the random number generation in this exercise one step further by generating a random number for each of the red, blue, and green color channels and combining them to make a completely random, new UIColor each time the button is pressed. What am I doing wrong? Also, how could I make this code more efficient? I feel as if I should not be writing these functions repeatedly.

Thanks for any help. Here is my code...

import Foundation
import UIKit

func redColor () -> Double {
    var unsignedArrayCount = UInt32(256)
    var unsignedRandomNumber = arc4random_uniform(unsignedArrayCount)
    var randomRedNumber = Double(unsignedRandomNumber)/255.0

    return randomRedNumber
}

func greenColor () -> Double {
    var unsignedArrayCount = UInt32(256)
    var unsignedRandomNumber = arc4random_uniform(unsignedArrayCount)
    var randomGreenNumber = Double(unsignedRandomNumber)/255.0

    return randomGreenNumber
}

func blueColor () -> Double {
    var unsignedArrayCount = UInt32(256)
    var unsignedRandomNumber = arc4random_uniform(unsignedArrayCount)
    var randomBlueNumber = Double(unsignedRandomNumber)/255.0

    return randomBlueNumber
}

func randomColor() -> UIColor {
    UIColor(red: redColor(), green: greenColor(), blue: blueColor(), alpha: 1.0)

    return randomColor()

}

1 Answer

kirkbyo
kirkbyo
15,791 Points
kirkbyo
kirkbyo
15,791 Points

Hey Michael,

I think I found a solution to your problem. What I decided to do was to create 1 function that will generate one random number as a CGFloat and then created another function that returns a random UIColor. 

struct colorWheel {

    // Generates a random Random Number
    func randomRGB() -> CGFloat {
        var unsignedArrayCount = UInt32(255)
        var unsignedRandomNumber = arc4random_uniform(unsignedArrayCount)
        var randomDouble = CGFloat(unsignedRandomNumber)

        return randomDouble
    }

    // Returns a random UIColor
    func randomColor() -> UIColor {
        let green = randomRGB() / 255.0
        let red = randomRGB() / 255.0
        let blue = randomRGB() / 255.0
        var randomColor = UIColor(red: red, green: green, blue: blue, alpha: 1.0)

        return randomColor
    }
}

I think the reason why your code was not working was because that UIColor as a double does not accept variables for some reason. That is I decided to use the UIColor that accepts CGFloat.

UIColor(red: CGFloat , green: CGFloat , blue: CGFloat, alpha: CGFloat)

Hope this helped,

Ozzie

Michael Henry
Michael Henry
14,601 Points
Michael Henry
Michael Henry
14,601 Points

Hi Ozzie - I see what you did there, and it makes sense - although shouldn't the red, blue, and green constants be variables so that the random numbers can change each time one clicks the button?

kirkbyo
kirkbyo
15,791 Points
kirkbyo
kirkbyo
15,791 Points

The reason why I used let was because we are not changing the value of it after we declare it. If you would like to read more about this, I found a helpful answer on Stack Over Flow

Ozzie

Michael Henry
Michael Henry
14,601 Points
Michael Henry
Michael Henry
14,601 Points

Thanks, Ozzie. Makes sense. Huge help.