Colors are usually stored in a resource file named colors.xml
in the /res/values/
folder.
They are defined by <color>
elements:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="colorPrimary">#3F51B5</color>
<color name="colorPrimaryDark">#303F9F</color>
<color name="colorAccent">#FF4081</color>
<color name="blackOverlay">#66000000</color>
</resources>
Colors are represented by hexadecimal color values for each color channel (0 - FF)
in one of the formats:
#RGB
#ARGB
#RRGGBB
#AARRGGBB
Legend
Defined colors can be used in XML with following syntax @color/name_of_the_color
For example:
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/blackOverlay">
Using colors in code
These examples assume this
is an Activity reference. A Context reference can be used in its place as well.
int color = ContextCompat.getColor(this, R.color.black_overlay);
view.setBackgroundColor(color);
int color = this.getResources().getColor(this, R.color.black_overlay);
view.setBackgroundColor(color);
In above declaration colorPrimary
, colorPrimaryDark
and colorAccent
are used to define Material design colors that will be used in defining custom Android theme in styles.xml
. They are automatically added when new project is created with Android Studio.