Learning Android, 2nd Edition

Chapter 12. Lists and Adapters

In this chapter, you will learn how to create selection widgets, such as a ListView. But this isn’t just a chapter about user interface elements. We are deepening our understanding of data from the previous chapter by learning how to read and use data from the status database. At first we’ll simply output it to the screen as scrollable text. You will then learn about adapters in order to connect your database directly with the list and create a custom adapter to implement some additional functionality. You will link this new activity with your main activity so that the user can both post and read tweets.

By the end of this chapter, your app will be able to post new tweets, as well as pull them from Twitter, store them in the local database, and let the user read the statuses in a nice and efficient UI. At that point, your app will have three activities and a service.

MainActivity

We’re going to create a new MainActivity. This activity will become the entry point into the application and for the most part will contain the TimelineFragment that will pull the data from the content provider and show it to the user.

Basic MainActivity

As in earlier chapters, the MainActivity just loads and inflates the layout, plus handles the Action Bar events, as Example 12-1 illustrates.

Example 12-1. MainActivity

package com.marakana.android.yamba;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem ...