Generate a random color (UIColor) in Objective-C

color.m

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CGFloat hue = ( arc4random() % 256 / 256.0 );  //  0.0 to 1.0
CGFloat saturation = ( arc4random() % 128 / 256.0 ) + 0.5;  //  0.5 to 1.0, away from white
CGFloat brightness = ( arc4random() % 128 / 256.0 ) + 0.5;  //  0.5 to 1.0, away from black
UIColor *color = [UIColor colorWithHue:hue saturation:saturation brightness:brightness alpha:1];

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thank you this is great for debugging. i set background color to random color when laying out many subviews

thank you this is great for debugging. i set background color to random color when laying out many subviews

Thank you!

Thank you!

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Thanks! its great for debugging.

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Quite a snippet there :)

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Thx a lot for ur share~

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Thanx, this is a great solution! :)

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Boom, what I needed, thanks.

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short and sweet. thanks for saving me some time!

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Thanks! This is great for debugging!

Thanks! This is great for debugging!

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Obrigado

Obrigado

Thank you for the snippet @kylefox ... I think that on line #26 one should divide by 255 .. mod 256 yields a number between 0 and 255 otherwise you'll never get to 1.0.

Thank you for the snippet @kylefox ... I think that on line #26 one should divide by 255 .. mod 256 yields a number between 0 and 255 otherwise you'll never get to 1.0.

Mine was a bit more long but it work

func changeBackgroundColor() {
// this has been taken from stackoverflow.com/questions/27390234/changing-main-view-controller-background-color-from-value-in-nsuserdefaults
//which gave me idea on how the background color works
// initialise defaults
let defaults = NSUserDefaults.standardUserDefaults()
// Start color off with a default value
var color = UIColor.grayColor()
var backcolor = 0

    if let backColor = defaults.objectForKey("backColor") as? String {
        // accessing the variable
        switch backColor {
        case "1": color = UIColor.redColor()
        case "2": color = UIColor.greenColor()
        case "3": color = UIColor.cyanColor()
        case "4": color = UIColor.yellowColor()
        case "5": color = UIColor.grayColor()
        case "6": color = UIColor.orangeColor()
        default: break




        }
    }

    //this has been lifted from :
    //stackoverflow.com/questions/24007129/how-does-one-generate-a-random-number-in-apples-swift-language
    //to give ideas on how random numbers work
    // and also cast from Int to String via
    //  stackoverflow.com/questions/24161336/convert-int-to-string-in-swift
    //to give ideas on how random numbers work


    NSUserDefaults.standardUserDefaults().setObject( "\(String (Int(arc4random_uniform(UInt32(6)+1))))", forKey: "backColor") //saving a random number and calling it backcolor
    NSUserDefaults.standardUserDefaults().synchronize() //
    view.backgroundColor = color

}

Mine was a bit more long but it work

func changeBackgroundColor() {
// this has been taken from stackoverflow.com/questions/27390234/changing-main-view-controller-background-color-from-value-in-nsuserdefaults
//which gave me idea on how the background color works
// initialise defaults
let defaults = NSUserDefaults.standardUserDefaults()
// Start color off with a default value
var color = UIColor.grayColor()
var backcolor = 0

    if let backColor = defaults.objectForKey("backColor") as? String {
        // accessing the variable
        switch backColor {
        case "1": color = UIColor.redColor()
        case "2": color = UIColor.greenColor()
        case "3": color = UIColor.cyanColor()
        case "4": color = UIColor.yellowColor()
        case "5": color = UIColor.grayColor()
        case "6": color = UIColor.orangeColor()
        default: break




        }
    }

    //this has been lifted from :
    //stackoverflow.com/questions/24007129/how-does-one-generate-a-random-number-in-apples-swift-language
    //to give ideas on how random numbers work
    // and also cast from Int to String via
    //  stackoverflow.com/questions/24161336/convert-int-to-string-in-swift
    //to give ideas on how random numbers work


    NSUserDefaults.standardUserDefaults().setObject( "\(String (Int(arc4random_uniform(UInt32(6)+1))))", forKey: "backColor") //saving a random number and calling it backcolor
    NSUserDefaults.standardUserDefaults().synchronize() //
    view.backgroundColor = color

}

Beauty!

Beauty!

Thanks !

Thanks !

Here is the snippet 
CGFloat redLevel    = rand() / (float) RAND_MAX;
CGFloat greenLevel  = rand() / (float) RAND_MAX;
CGFloat blueLevel   = rand() / (float) RAND_MAX;

self.view.backgroundColor = [UIColor colorWithRed: redLevel
                                            green: greenLevel
                                             blue: blueLevel
                                            alpha: 1.0];

Here is the snippet 
CGFloat redLevel    = rand() / (float) RAND_MAX;
CGFloat greenLevel  = rand() / (float) RAND_MAX;
CGFloat blueLevel   = rand() / (float) RAND_MAX;

self.view.backgroundColor = [UIColor colorWithRed: redLevel
                                            green: greenLevel
                                             blue: blueLevel
                                            alpha: 1.0];

Thank you very much!

Thank you very much!

Thanks

Thanks

Swift:

    let hue = CGFloat(Double(arc4random() % 256) / 256.0) // 0.0 to 1.0
    let saturation = CGFloat(Double(arc4random() % 128) / 266.0 + 0.5) // 0.5 to 1.0, away from white
    let brightness = CGFloat(Double(arc4random() % 128) / 256.0 + 0.5) // 0.5 to 1.0, away from black
    return UIColor(hue: hue, saturation: saturation, brightness: brightness, alpha: 1.0)

Swift:

    let hue = CGFloat(Double(arc4random() % 256) / 256.0) // 0.0 to 1.0
    let saturation = CGFloat(Double(arc4random() % 128) / 266.0 + 0.5) // 0.5 to 1.0, away from white
    let brightness = CGFloat(Double(arc4random() % 128) / 256.0 + 0.5) // 0.5 to 1.0, away from black
    return UIColor(hue: hue, saturation: saturation, brightness: brightness, alpha: 1.0)

Thanks!

Thanks!

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Thx!

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Nice, thank you!

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Thanks a lot

I have a color code like "15233421". How can I consider alpha value while using any of the solution?

I have a color code like "15233421". How can I consider alpha value while using any of the solution?

Thank you! 👍

Thank you! 👍

Thank you so much for this share. It helps people like me who are new to iOS programming in ObjC

Thank you so much for this share. It helps people like me who are new to iOS programming in ObjC

Great...!

Great...!