If you have your hex value, and your just wondering what the value for the alpha would be, this snippet may help:
const alphaToHex = (alpha => {_x000D_
if (alpha > 1 || alpha < 0 || isNaN(alpha)) {_x000D_
throw new Error('The argument must be a number between 0 and 1');_x000D_
}_x000D_
return Math.ceil(255 * alpha).toString(16).toUpperCase();_x000D_
})_x000D_
_x000D_
console.log(alphaToHex(0.45));Just came across this and the short code for transparency is simply #00000000.
Just use this :
android:background="#00FFFFFF"
it will do your work.
Adding to the other answers and doing nothing more of what @Maleta explained in a comment on https://stackoverflow.com/a/28481374/1626594, doing alpha*255 then round then to hex. Here's a quick converter http://jsfiddle.net/8ajxdLap/4/
function rgb2hex(rgb) {_x000D_
var rgbm = rgb.match(/^rgba?[\s+]?\([\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?,[\s+]?((?:[0-9]*[.])?[0-9]+)[\s+]?\)/i);_x000D_
if (rgbm && rgbm.length === 5) {_x000D_
return "#" +_x000D_
('0' + Math.round(parseFloat(rgbm[4], 10) * 255).toString(16).toUpperCase()).slice(-2) +_x000D_
("0" + parseInt(rgbm[1], 10).toString(16).toUpperCase()).slice(-2) +_x000D_
("0" + parseInt(rgbm[2], 10).toString(16).toUpperCase()).slice(-2) +_x000D_
("0" + parseInt(rgbm[3], 10).toString(16).toUpperCase()).slice(-2);_x000D_
} else {_x000D_
var rgbm = rgb.match(/^rgba?[\s+]?\([\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?,[\s+]?(\d+)[\s+]?/i);_x000D_
if (rgbm && rgbm.length === 4) {_x000D_
return "#" +_x000D_
("0" + parseInt(rgbm[1], 10).toString(16).toUpperCase()).slice(-2) +_x000D_
("0" + parseInt(rgbm[2], 10).toString(16).toUpperCase()).slice(-2) +_x000D_
("0" + parseInt(rgbm[3], 10).toString(16).toUpperCase()).slice(-2);_x000D_
} else {_x000D_
return "cant parse that";_x000D_
}_x000D_
}_x000D_
}_x000D_
_x000D_
$('button').click(function() {_x000D_
var hex = rgb2hex($('#in_tb').val());_x000D_
$('#in_tb_result').html(hex);_x000D_
});body {_x000D_
padding: 20px;_x000D_
}<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
Convert RGB/RGBA to hex #RRGGBB/#AARRGGBB:<br>_x000D_
<br>_x000D_
<input id="in_tb" type="text" value="rgba(200, 90, 34, 0.75)"> <button>Convert</button><br>_x000D_
<br> Result: <span id="in_tb_result"></span>BE AWARE
In HTML/CSS (browser code) the format is #RRGGBBAA with the alpha channel as last two hexadecimal digits.
Here is the table of % to hex values:
Example: For 85% white, you would use #D9FFFFFF.
Here 85% = "D9" & White = "FFFFFF"
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
How is it calculated?
FF is number written in hex mode. That number represent 255 in decimal. For example, if you want 42% to calculate you need to find 42% of numbeer 255 and convert that number to hex. 255 * 0.42 ~= 107 107 to hex is "6B – maleta
Source: Stackoverflow.com