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Android

Posted by Akshay Shivpuri
Akshay Shivpuri
2,917 Points

Setting RGBA to background color

Hi there, I want to set a background color of RGBA value(as it has opacity) to a TextView. 

mAnswerlabel.setBackgroundColor(????);

I've my RGBA value as (0, 0, 0, 0.2). I googled a lot about it and found that only int value can be passed in setBackgroundColor and SetAlpha property would be used, but I'm not able to use it.

I hope someone can help me on this.

Thanks in advance, Akshay

5 Answers

Marcus Vieira
Marcus Vieira
7,877 Points

Try this:

mAnswerlabel.setBackgroundColor(Color.argb(alpha, r, g, b));

edit: added argb

Ernest Grzybowski
Ernest Grzybowski
Treehouse Project Reviewer
Ernest Grzybowski
Ernest Grzybowski
Treehouse Project Reviewer

I prefer to set up my colors in hex. You can do something like view.setBackground(0x80FF0000)

  • 0x signifies hex.
  • 80 means 50% alpha
  • FF for red
  • 0000 for no blue or green

As with most things in programming, there are many ways to accomplish the same task at hand. You can try any of these:

myView.setBackgroundColor(Color.argb(a_int, r_int, g_int, b_int));
myView.setBackgroundColor(Color.parseColor("#AARRGGBB"));
myView.setBackgroundColor(0xAARRGGBB);

For an alpha of 0.2, this is technically 20% so you could just use 0x33FF0000 for a 0.2 alpha red color.

I use https://kuler.adobe.com to find my hex color, and for alpha in hex I use:

100% — FF 95% — F2 90% — E6 85% — D9 80% — CC 75% — BF 70% — B3 65% — A6 60% — 99 55% — 8C 50% — 80 45% — 73 40% — 66 35% — 59 30% — 4D 25% — 40 20% — 33 15% — 26 10% — 1A 5% — 0D 0% — 00

Curious about hex vs rgb? Read here and here.

Akshay Shivpuri
Akshay Shivpuri
2,917 Points

Thanks Ernest Grzybowski ! That was a detailed answer. :)

Akshay Shivpuri
Akshay Shivpuri
2,917 Points

And btw, we can also use XML format for setting background color.

Akshay Shivpuri
Akshay Shivpuri
2,917 Points
Akshay Shivpuri
Akshay Shivpuri
2,917 Points

But it has alpha value also i.e. rgba and not rgb where alpha value is in decimal(.2)

Marcus Vieira
Marcus Vieira
7,877 Points

I updated my answer :)

Akshay Shivpuri
Akshay Shivpuri
2,917 Points
Akshay Shivpuri
Akshay Shivpuri
2,917 Points

But then again how will it accept "a" as 0.2. Only int values can be passed

Akshay Shivpuri
Akshay Shivpuri
2,917 Points
Akshay Shivpuri
Akshay Shivpuri
2,917 Points

Or wait, maybe I found out. "a" value would range from 0 to 255 and in this case for 0.2, would approximately be around 55. Thanks for your help. :)

Ernest Grzybowski
Ernest Grzybowski
Treehouse Project Reviewer

Edited my answer.