Android Developer Toolbox

If you've read Getting Started and Developing Apps, then you know how to build an Android application. (If you haven't read those sections you should now.) Android is a large system though, and there's a lot to learn. The best apps always make the most of the system's features. The links below tell you how to write code that bends the system to your will, allowing you to create cool custom components and do amazing things with the many available APIs. A manifesto explaining a technical...

Declaring and Enforcing Permissions

To enforce your own permissions, you must first declare them in your AndroidManifest. xml using one or more For example, an application that wants to control who can start one of its activities could declare a permission for this operation as follows Note that both a label and description should be supplied for the permission. These are string resources that can be displayed to the user when they are viewing a list of permissions (android label) or details on a single permission ( android...

Writing Efficient Android Code

There's no way around it Android devices are embedded devices. Modern handsets may be more like small handheld computers than mere phones these days, but even the fastest, highest-end handset doesn't even come close to the capabilities of even a modest desktop system. That's why it's very important to consider performance when you write Android applications. These systems are not that fast to begin with and they are also constrained by their battery life. This means that there's not a lot of...

Developing Android Applications

You can develop Android applications wit h the same high-quality tools you use to develop Java applications. The Android core libraries provide the functionality needed to build some amazingly rich mobile applications, and the Android development tools make running, debugging, and testing your applications a snap. This section explains the ins and outs of developing Android applications. It outlines the philosophy behind the system and then describes each of the key subsystems in detail. After...

Tutorial A Notepad Application

The tutorial in this section gives you a hands-on introduction to the Android framework and the tools you use to build applications on it. Starting from a preconfigured project file, it guides you through the process of developing a simple notepad application and provides concrete examples of how to set up the project, develop the application logic and user interface, and then compile and run the application. The tutorial presents the notepad application development as a set of exercises (see...

Creating a Content Provider

Here is how to create your own content provider to act as a public source for reading and writing a new data type 2. Define a public static final ContentURI named CONTENT_URI. This is the string that represents the full content URI that your content provider handles. You must define a unique string for this value the best solution is to use the fully-qualified class name of your content provider (lowercase). So, for example public static final ContentURI CONTENT_URI ContentURI.create( 3. Create...

Development Tools

The Android SDK includes a variety of custom tools that help you develop mobile applications on the Android platform. The most important of these are the Android Emulator and the Android Development Tools plugin for Eclipse, but the SDK also includes a variety of other tools for debugging, packaging, and installing your applications on the emulator. A virtual mobile device that runs on your computer. You use the emulator to design, debug, and test your applications in an actual Android run-time...

Using a Content Provider to Store and Retrieve Data

This section describes how to store and retrieve data using a content provider implemented by you or anyone else. Android exposes a number of content providers for a wide range of data types, from music and image files to phone numbers. You can see a list of content providers exposed through the convenience classes in the android.provider package. Android's content providers are loosely linked to their clients. Each content provider exposes a unique string a URI identifying the type of data...

Android Architecture

The following diagram shows the major components of the Android operating system. Each section is described in more detail below. Android will ship with a set of core applications including an email client, SMS program, calendar, maps, browser, contacts, and others. All applications are written using the Java programming language.