56 CHAPTER 2: Configuring Your Android App Development System
The Android Intent and IntentFilter classes are used to communicate within an Android application,
between components such as Activities and Services, as well as outside of your Android application.
This External communication is usually with other Android applications, which are not part of your
Android application, but which your application will need to communicate with, to synchronize with,
or to exchange data with. Android is a very complex subject, so expect each chapter to become
more complex!
UI Design: Adding User Controls to Your Apps
In Chapter 8, we will get into the plethora of facilities that Android provides to developers to design
UI layouts containing UI elements (called “widgets” in Android), so that your app’s users can
“interface” with your application. That’s why it’s a “user interface!”
This design process is called UI Design, and you have already downloaded and installed the Pencil
2.0.5 UI design tool on your workstation in the previous chapter, so you can prototype UI designs!
In Chapter 8, we will focus on looking at Android’s flexible UI design classes, which are based on
Android’s ViewGroup class. UI layouts can be “nested” within each other, or simply utilized on their
own, in order to create any UI design, no matter how complex, that your application might require to
“bridge” your application’s functionality over to its users.
We will take a look at some of the most often used UI design classes in Android, commonly called
“layout containers,” and how these will allow developers to create UI designs quickly and efficiently.
Graphics Design: Add Visuals to Your Apps
In Chapter 9, we will start to get into adding new media elements to your Android applications by
looking at static (fixed) graphics. These are implemented using digital images, and we will take a look
at the basics of digital imaging as well as at the digital image formats that are supported by Android.
We will start building highly visual UI designs that incorporate graphic design elements, again by
using the XML foundation that you will have learned during the previous chapters. As we are building
one chapter upon another, this will continue to build on your newfound knowledge of Android
Activity classes, XML markup, Android screen design, View widgets, and ViewGroup layout classes.
Because Android smartwatches, smartphones, tablets, and iTV sets feature Organic Light-Emitting
Diode (OLED) wide video graphics array (WVGA, or 800x480) and high-definition television (HDTV, or
1920x1080) screens in the current market “line-up” of Android products, Android display screens are
impressive enough these days to allow some amazing user experiences to be created using graphic
design elements.
Since this is an area where Android development starts to get interesting, I decided to incorporate
how to leverage new media assets in your Android applications, so that your work can stand far
apart from the crowd. Android has a plethora of support for new media assets. Just because this is
an Absolute Beginner title doesn’t mean we should shy away from complexity!
We will look at several different image formats that are supported in Android and how they differ from
each other. We will look at their strengths and weaknesses, and which are the preferred ones to use
for your Android applications development. We’ll look at why Android prefers certain image formats
over others.