Android: Generate random color on click?

to get random color values you can use this method:

public int getRandomColor(){
   Random rnd = new Random();
   return Color.argb(255, rnd.nextInt(256), rnd.nextInt(256), rnd.nextInt(256));
}

then apply to your views:

myView.setBackgroundColor(getRandomColor());

Random rnd = new Random();
paint.setARGB(255, rnd.nextInt(256), rnd.nextInt(256), rnd.nextInt(256));

or

Random rnd = new Random(); 
int color = Color.argb(255, rnd.nextInt(256), rnd.nextInt(256), rnd.nextInt(256));   
view.setBackgroundColor(color);

Though in your case it seems that you want to create a new drawable and assign it to your view. What is actually the drawable in your case? Is it an image, shape, fill...

So if you’re looking for a beautiful color palette, Maybe It's Not Such A Great Idea To use totally random values. This approach might not yield the best results, It always ends up with a selection of similar colors that way too dark or way too bright.

Semi-random approach (Java):

If you need some fresh and shiny colors then use the following simple class, that I wrote previously when I had the same issues. It's semi-random and uses a predefined color palette:

class RandomColors {
    private Stack<Integer> recycle, colors;

    public RandomColors() {
        colors = new Stack<>();
        recycle =new Stack<>();
        recycle.addAll(Arrays.asList(
                0xfff44336,0xffe91e63,0xff9c27b0,0xff673ab7,
                0xff3f51b5,0xff2196f3,0xff03a9f4,0xff00bcd4,
                0xff009688,0xff4caf50,0xff8bc34a,0xffcddc39,
                0xffffeb3b,0xffffc107,0xffff9800,0xffff5722,
                0xff795548,0xff9e9e9e,0xff607d8b,0xff333333
                )
        );
    }

    public int getColor() {
        if (colors.size()==0) {
            while(!recycle.isEmpty())
                colors.push(recycle.pop());
            Collections.shuffle(colors);
        }
        Integer c= colors.pop();
        recycle.push(c);
        return c;
    }
}

Random approach (Java):

But if you're still considering use random approach you may want use this single line instead of multiple lines of code :

int color= ((int)(Math.random()*16777215)) | (0xFF << 24);

The purpose of using this (0xFF << 24) is to set the alpha value to the maximum that means zero transparency.

semi-random (Kotlin)

class RandomColors() {
    private val recycle:Stack<Int> = Stack()
    private val colors:Stack<Int> = Stack()
    init {
        recycle.addAll(
            Arrays.asList(
                // ARGB hex to int >> (0xFFEE5670.toInt(),...)
                -0xbbcca, -0x16e19d, -0x63d850, -0x98c549,  
                -0xc0ae4b, -0xde690d, -0xfc560c, -0xff432c,
                -0xff6978, -0xb350b0, -0x743cb6, -0x3223c7,
                -0x14c5, -0x3ef9, -0x6800, -0xa8de,
                -0x86aab8, -0x616162, -0x9f8275, -0xcccccd
            )
        )
    }

    fun getColor(): Int {
        if (colors.size == 0)
            while (!recycle.isEmpty()) colors.push(recycle.pop())
            Collections.shuffle(colors)
        val c = colors.pop()
        recycle.push(c)
        return c
    }
}

Random approach (Kotlin):

val color = (Math.random() * 16777215).toInt() or (0xFF shl 24)