Android - Change only the alpha TextView's text

Question

Say I have this code:

int color = tv.getCurrentTextColor();

How would I change only the Alpha on this color?

For Example:

if color is 0x00ffffff, how would I change it to 0xffffffff ?

Is there a method for that or I need to do some hex/int manipulations?

Answer 1

Well, the straight answer to your question of "if color is 0x00ffffff, how would I change it to 0xffffffff ?" to simply to use compound bitwise or: color |= 0xff000000;.

But I reckon maybe some co-workers would rather you didn't do this kind of thing on the java-side of Android development: you have a wonderful helper class called graphics.Color provided by Android! It does just the same things underneath, but'll really help your code readibility, especially considering that an int type color in android isn't necessarily a hex color value but could also point to an artbirary id of a resource in the color xml. Argh.

An eg would be:

int color = tv.getCurrentTextColor();
int newColor = Color.argb(yourNewAlphaVal, Color.red(color), Color.green(color), Color.blue(color))

Not fast, but I'm guessing you don't need it to be.

Of course, this is a personal opinion about what to use here, and I hope this helps!