How to tile a background image in Android

For one of the apps I'm working on I wanted to have a nice pixel pattern tiled behind my widgets.
After a little bit of hunting around I found this tutorial, and I thought I'd clean up the lessons within and show you how.

Here's the contents of my main.xml layout file,

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@drawable/backrepeat"
    android:gravity="center_horizontal"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />  

</LinearLayout>

which is referenced in code in the standard way like this:

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

...// (rest of onCreate method continues here..)

Now note this line:

android:background="@drawable/backrepeat"


What's going on there?
.. Glad you asked!

Here's a quick screenshot of the contents of one of my drawable folders in my project:

What is this
backrepeat.xml?

Well, here's the contents of that file here:

<bitmap
xmlns:android="http://schemas.android.com/apk/res/android"
android:src="@drawable/scale1"
android:tileMode="repeat"
android:dither="true" />


Can you see what's going on?
Backrepeat.xml defines an instance of the BitmapDrawable class, and that class references our simple scale1.jpg, located in the drawable-hdpi folder.

Simply by adding the:

<bitmap
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:src="@drawable/scale1"
    android:tileMode="repeat"
    android:dither="true" />

line in bold, we are able to achieve results such as this:

Easy isn't it?

One thing to keep in mind is that you should have folders drawable-hdpi, drawable-mdpi & drawable-ldpi, you'll need to add this backrepeat.xml file and the relevant images to each of these to allow this functionality in high, medium and low dpi (dots per inch) screen sizes.

Enjoy.