Setting background colour of Android layout element

I am trying to, somewhat clone the design of an activity from a set of slides on Android UI design. However I am having a problem with a very simple task.

I have created the layout as shown in the image, and the header is a TextView in a RelativeLayout. Now I wish to change the background colour of the RelativeLayout, however I cannot seem to figure out how.

I know I can set the android:background property in the RelativeLayout tag in the XML file, but what do I set it to? I want to define a new colour that I can use in multiple places. Is it a drawable or a string?

Additionally I would expect there to be a very simple way to this from within the Eclipse Android UI designer that I must be missing?

I am a bit frustrated currently, as this should be an activity that is performed with a few clicks at maximum. So any help is very appreciated. :)

Solution 1:

You can use simple color resources, specified usually inside res/values/colors.xml.

<color name="red">#ffff0000</color>

and use this via android:background="@color/red". This color can be used anywhere else too, e.g. as a text color. Reference it in XML the same way, or get it in code via getResources().getColor(R.color.red).

You can also use any drawable resource as a background, use android:background="@drawable/mydrawable" for this (that means 9patch drawables, normal bitmaps, shape drawables, ..).

Solution 2:

The above answers are nice.You can also go like this programmatically if you want

First, your layout should have an ID. Add it by writing following +id line in res/layout/*.xml

<RelativeLayout ...
...
android:id="@+id/your_layout_id"
...
</RelativeLayout>

Then, in your Java code, make following changes.

RelativeLayout rl = (RelativeLayout)findViewById(R.id.your_layout_id);
rl.setBackgroundColor(Color.RED);

apart from this, if you have the color defined in colors.xml, then also you can do programmatically :

rl.setBackgroundColor(ContextCompat.getColor(getContext(), R.color.red));

Solution 3:

You can use android:background="#DC143C", or any other RGB values for your color. I have no problem using it this way, as stated here

Solution 4:

The

res/values/colors.xml.

<color name="red">#ffff0000</color>
android:background="@color/red"

example didn't work for me, but the

android:background="#(hexidecimal here without these parenthesis)"

worked for me in the relative layout element as an attribute.

Solution 5:

If you want to change a color quickly (and you don't have Hex numbers memorized) android has a few preset colors you can access like this:

android:background="@android:color/black"

There are 15 colors you can choose from which is nice for testing things out quickly, and you don't need to set up additional files.

Setting up a values/colors.xml file and using straight Hex like explained above will still work.