This chapter introduced key features of the Eclipse IDE and the ADT Visual Layout Editor. You used the Visual Layout Editor to create a working Android app without writing any code. You used the TextView and ImageView GUI components to display text and images, respectively, and you arranged these components in a RelativeLayout. You edited the properties of GUI components to customize them for your app. You then tested the app in an Android Virtual Device (AVD). Finally, we presented a detailed walkthrough of the XML markup that generates the GUI.
In the next chapter we introduce how to program Android apps using Java. Android development is a combination of GUI design, and Java and XML coding. Java allows you to specify the behavior of your apps. You’ll develop the Tip Calculator app, which calculates a range of tip possibilities when given a restaurant bill amount. You’ll design the GUI and add Java code to specify how the app should process user inputs and display the results of its calculations.