Learning Android

Chapter 4. Main Building Blocks

In this chapter, you will learn about the big blocks in Android. We’ll give you a high-level overview of what activities are, how intents work, why services are cool, how to use broadcast receivers and content providers to make your app scale, and much more.

By the end of this chapter, you will understand the main Android components for building applications. You should conceptually know when you’d use what component. You will also see how these components relate to a real-world application.

What Are Main Building Blocks?

The main building blocks are components that you use as an application developer to build Android apps. They are the conceptual items that you put together to create a bigger whole. When you start thinking about your application, it is good to take a top-down approach. You design your application in terms of screens, features, and the interactions between them. You start with conceptual drawing, something that you can represent in terms of “lines and circles.” This approach to application development helps you see the big picture—how the components fit together and how it all makes sense.

A Real-World Example

Let’s say that we want to build a Twitter app. We know that the user should be able to post status updates. We also know the user should be able to see what her friends are up to. Those are basic features. Beyond that, the user should also be able to set her username and password in order to log into her Twitter account. So, ...