2.9. Wrap-Up

In this chapter, you used the Android Developer Tools IDE to build the Welcome app that displayed a welcome message and two images without writing any code. You created a simple GUI using the IDE’s Graphical Layout editor and configured properties of GUI components using the Properties window.

The app displayed text in a TextView and pictures in ImageViews. You modified the TextView from the default GUI to display the app’s text centered in the GUI, with a larger font size and in one of the standard theme colors. You also used the Graphical Layout editor’s Palette of GUI controls to drag and drop ImageViews onto the GUI. Following best practices, you defined all strings and numeric values in resource files in the project’s res folder.

You learned that Android has accessibility features to help people with various disabilities use their devices. We showed how to enable Android’s TalkBack to allow a device to speak screen text or speak text that you provide to help the user understand the purpose and contents of a GUI component. We discussed Android’s Explore by Touch feature, which enables the user to touch the screen to hear TalkBack speak what’s on the screen near the touch. For the app’s ImageViews, you provided content descriptions that could be used with TalkBack and Explore by Touch.

Finally, you learned how to use Android’s internationalization features to reach the largest possible audience for your apps. You localized the Welcome app with Spanish strings for the TextView’s text and the ImageViews’ accessibility strings, then tested the app on an AVD configured for Spanish.

Android development is a combination of GUI design and Java coding. In the next chapter, you’ll develop a simple Tip Calculator app by using the Graphical Layout editor to develop the GUI visually and Java programming to specify the app’s behavior.