Building Hybrid Android Apps with Java and JavaScript

Chapter 3. Android Fundamentals

In this chapter, we will introduce you to the basics of the Android application framework. You can skip to the next chapter, if you are already comfortable with Android.

Android Application Architecture

An Android application is an archive that includes a combination of compiled Android components, a manifest file, and a bunch of resources and assets. We will look at these in more detail in this chapter. The archive is a file with an APK (Android package) extension. To put it simply, an APK file is a fancy JAR file. More details on the APK file format can be found at the Wikipedia website for APK definition.

Android application framework and middleware are highly componentized and very flexible for UX customizations on a per-application basis. Android is secure, in that applications run in their own address space and an isolated sandbox that has limited or no access to other applications’ data.

Despite all the security features, the Android application framework has been written from the ground up to allow application components to cooperate with those declared in the same or other apps to deliver a rich experience. This functionality is quite unique to Android and has been one of key driving factors for its success among developers. This topic will be further detailed later.

Key Android Components

The following sections outline the components that are necessary to programming for Android.

Dalvik Virtual Machine (DVM)

Android applications run on a mobile ...