8.10. Wrap-Up

In this chapter, you created an Address Book app that enables users to add, view, edit and delete contact information that’s stored in a SQLite database. You defined common GUI component attribute–value pairs as XML style resources, then applied the styles to all components that share those values by using the components’ style attribute. You added a border to a TextView by specifying a Drawable as the value for the TextView’s android:background attribute and you created a custom Drawable using an XML representation of a shape. You also used Android standard icons to enhance the visual appearance of the app’s menu items.

When an Fragment’s primary task is to display a scrollable list of items, you learned that you can extend class ListFragment to create a Fragment that displays a ListView in its default layout. You used this to display the contacts stored in the app’s database. You bound data to the ListView via a CursorAdapter that displayed the results of a database query.

In this app’s Activity, you used FragmentTransactions to add Fragments to and replace Fragments in the GUI dynamically. You also used the Fragment back stack to support the back button for returning to a previously displayed Fragment and to allow the app’s Activity to programmatically return to previous Fragments.

We demonstrated how to communicate data between Fragments and a host Activity or the Activity’s other Fragments via interfaces of callback methods that are implemented by the host Activity. You also used Bundles to pass arguments to Fragments.

You used a subclass of SQLiteOpenHelper to simplify creating the database and to obtain a SQLiteDatabase object for manipulating a database’s contents. You processed query results via a Cursor. You used subclasses of AsyncTask to perform database tasks outside the GUI thread and return results to the GUI thread. This allowed you to take advantage of Android’s threading capabilities without directly creating and manipulating threads.

In Chapter 9, we discuss the business side of Android app development. You’ll see how to prepare your app for submission to Google Play, including making icons. We’ll discuss how to test your apps on devices and publish them on Google Play. We discuss the characteristics of great apps and the Android design guidelines to follow. We provide tips for pricing and marketing your app. We also review the benefits of offering your app for free to drive sales of other products, such as a more feature-rich version of the app or premium content. We show how to use Google Play to track app sales, payments and more.