CODEWITHSUNDEEP
javaandroidhex
mmattax
mmattax

Reputation: 27670

Help storing color hexadecimals as an integer in Java

I need to represent the hex color #F0FFF0 in an android application (stored as an integer). I am storing this as:

int color = 0xF0FFF0;

But the color seems way off when being rendered (in fact, it's black). Am I storing the color incorrectly?

Upvotes: 2

Views: 4371

Answers (4)

BlondeFurious
BlondeFurious

Reputation: 12259

Android uses Hex ARGB values, which are formatted as #AARRGGBB. That first pair of letters, the AA, represent the Alpha Channel. You must convert your decimal opacity values to a Hexdecimal value. Here are the steps:

Alpha Hex Value Process

  1. Take your opacity as a decimal value and multiply it by 255. So, if you have a block that is 50% opaque the decimal value would be .5. For example: .5 x 255 = 127.5
  2. The fraction won't convert to hex, so you must round your number up or down to the nearest whole number. For example: 127.5 rounds up to 128; 55.25 rounds down to 55.
  3. Enter your decimal value in a decimal to hexadecimal converter, like this http://www.binaryhexconverter.com/decimal-to-hex-converter, and convert your values
  4. If you only get back a single value, prefix it with a zero. For example, if you're trying to get 5% opacity and your going through this process you'll end up with the hex value of D. Add a zero in front of it so it appears as 0D.

That's how you find the alpha channel value. I've taken the liberty to put together a list of values for you. Enjoy!

Hex Opacity Values

  • 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

Upvotes: 6

pedr0
pedr0

Reputation: 3011

Not you didn't.

You have to add Alpha channel.

For your example is :

int color = 0xFFF0FFF0

I think it works!

Upvotes: 1

C0deAttack
C0deAttack

Reputation: 24667

I've always specified my colours with the alpha value, ie:

int color = 0xFFF0FFF0;

I'm not sure if the leading FF will be implicit if it's omitted however.

Upvotes: 3

f20k
f20k

Reputation: 3106

Perhaps you need to set the alpha too. ie.

int color = 0xFFF0FFF0;

where the first two FF represent the alpha as being completely opaque. See: http://developer.android.com/reference/android/graphics/Color.html

Upvotes: 6

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