Preview text in Android layout XML

When designing layouts in XML, it’s useful to be able to work with a preview containing some sample text.

Rather than hard-coding a load of text in the layout (which is bad because it slows down view inflation), you can use the tools namespace to achieve the same effect without the runtime cost.

Instead of this:

 <TextView
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:text="Lorem Ipsum"/>

…do this!

 <TextView
   xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   tools:text="Lorem Ipsum"/>