Ways To Customize Android Device

By Author: Saravana Pandian
Total Articles: 1
Comment this article

In the smart phone market, Android is already the most popular OS in the world with more than a 84% market share. It has been growing steadily since its launch in non-smart phone markets as well. Apart of the consumer electronics market, Android is gaining wide acceptance in other segments including medical, automotive, industrial and defense sectors. It is estimated that Android Auto will be available in more than 31 million cars by 2020. Cheaper and powerful multi-core processors and low cost memories are fueling its growth with continuous innovation from Google.

This blog introduces the readers to some of the possible mechanisms available to customize the Android OS. Exact information about how to modify the AOSP to achieve these are covered in a series of blogs. Kindly note that this blog is for BSP developers and engineers working with the AOSP to optimize their Android system. For tips about customize your COTS Android phone or tablet, this is not the place and Google will be a better guide.

AOSP Features
Android is available as open-source offering, though tightly controlled by Google. Termed as ...
... AOSP – Android Open Source Project, it is available for everyone to use in their device. Called the Stock Android interface, it comes with complete user interface with all necessary features like home screen, Phone calling App, settings, browsers. Once installed in a device, the Google Play Store app is also available there by providing user access to millions of apps in the store.

Except for few closed source binaries provided by silicon vendors like the graphics acceleration, video decoding libraries, etc, needed to enable Android on a custom device, all other components have their source code open-sourced. So this provides a lot of opportunities to modify them and present in a customized way.

Need for customization
The AOSP interface is designed mostly for a consumer electronic device application typically a smart phone or a tablet with a home screen capable of supporting widgets and shortcuts. There is also a status bar in the top where notification icons are present along with the pull down option. An action bar is presented in the bottom if configured so. But this kind of interface might not be suited for other kinds of applications.

For example, if the device is being used in an Auto-infotainment system, we expect a home screen which consolidates the status of the vehicle with limited but larger icons. It should be understandable with limited attention span and provide seamless integration with the physical buttons present around the screen. Similarly for a PoS terminal kind of use case, there is no expectation of a home screen but rather a single application that will be able to present different information about the inventory, billing kiosks etc. There is no need for even the status bar or the action bar as user should be presented larger buttons for faster access. So each kind of application needs the Android to be presented in some kind of customized ways.

Further OEMs prefer to keep the User experience in line with their product branding. It might be the color themes, iconography, fonts being used, typography etc. It calls for significant customization to achieve this.

Types of customization
There are multiple ways the Stock Android Image can be customized. Right from the UI aspects to the internal services and SDK, Google provide options to modify each and every aspect of the Android. While many are straight forward, some needs a little bit of tweaking to achieve the necessary functionality.

Some of them are
• Boot Animation
• Status Bar
• Action Bar
• Application Packages
• Themes
• Home Screen
• New Services

In the following section, we go through each of them one by one.

Boot Animation
First and foremost customization is the show the manufacturer logo. By default, the AOSP shows an Android flashing image during Android boot up. Essentially the Android Boot Animation is an zip archive containing a set of PNG files along with a text file describing the timing associated with showing these images sequentially. It is possible to loop back to a previous image there by creating a repeated video effect. As the boot logo is shown quiet later after powered on, the user may not be getting a feel of responsiveness on pressing the power button. So it is important to show the logo earlier when the boot loader is executed.

Status Bar
The status bar is part of the application that is started when the Android is started. All the information is available as xml file which can be customized. For example, if the device is powered by external power supply, there is a no need for battery symbol. Also if there is no GSM modem, then there is no purpose served by showing signal strength. These can be modified by playing around with the xml file.

Action Bar
It is possible to place the action bar anywhere in the screen – bottom, left or right. And it can be removed altogether. Android provides options to the developer to choose the preferred way. Also it is possible to add new action buttons and remove existing ones.

Packages
The number of packages present in the stock source could be more than needed for a particular application. It is possible to customize them using the files available under the device directory.

Themes
To completely change the way the overall Android user interface looks, the theme can be changed easily by modifying the relevant files. Languages supported can also be controlled based on the target customer base.

Network
The default list of network service providers and configurations corresponding to them can also be modified.

Home Screen
The Android comes with a default home screen application. It is can be modified in a way needed just like any other application. Further if the device has to boot into a particular application rather a the default one, the “LAUNCH” property has to be added in the App manifest file. Once displayed, up on pressing the home button, Android shows the selector dialog and asks the user to choose the App to be used as the home screen. But since it need not be asked, the default home screen package can be removed and the new App can be packed during image creation.

Creating new Services
While all the above options discusses the possibilities of modifying the User Interface, there are many other requirements for changing under the hood. Once such need is the creation of new services. For example, there might be a specific communication protocol to be running in the background that needs to be exported to the applications. Please note that the changes in SDK causes major changes and CTS has to be done carefully.

Thus Android provides multiple mechanisms to customize it based on the target application. We hope this blog has given a quick overview to these techniques. Upcoming blogs will cover each of these topics in detail.

About Embien
Embien Technologies is a specialist in Android Technologies and has ported various versions of Android on to different hardware platforms. We have customized the stock code for various products and applications including new HAL creation, custom services, Theming and many other UI changes. We also specialize reducing the power consumption and boot-time of the system resulting in longer battery life and better user experience. Embien also conducts Corporate Training on Android internals. Check out our Android Services page for more details.