Android Architecture: A Comprehensive Guide for Developers
Android architecture refers to the design and structure of the Android operating system.
Understanding the architecture of Android is essential for developers who want to build high-quality Android applications that are efficient, stable, and scalable.
In this article, we will provide you with a comprehensive guide to the architecture of Android.
There are five main layers in Android architecture:
- Linux Kernel Layer
- Native C/C++ Libraries Layer
- Android Runtime Layer (ART)
- Application Framework Layer
- Applications Layer
Each of these layers plays a crucial role in the overall functioning of the Android operating system, Lets explore each of them in detail.
Linux Kernel Layers
The Linux Kernel Layer is the bottom layer of the Android architecture.
The Linux kernel serves as the underlying layer that manages the hardware resources of the device, including the camera, touchscreen, sensors, and networking components.
The kernel provides low-level hardware abstraction and access to device drivers, which are used to control the various hardware components.
Android uses the Linux Kernel as its foundation, making it a stable and secure operating system.
Open-source nature of the Linux kernel is one of the key advantages of the Android platform. The Linux kernel is released under the GNU General Public License (GPL), which permits anyone to view, modify, and distribute its code.
As a result, developers have been able to customize and optimize the Linux kernel specifically for use in mobile devices, resulting in improved performance, battery life, and overall user experience.
It provides a hardware abstraction layer (HAL) that allows the Android platform to be hardware independent. HAL facilitates seamless communication and interoperability between hardware and software components by serving as a bridge between platform-specific hardware drivers and Android’s high-level framework.
Native C/C++ Libraries Layers
The Native Libraries Layer is built on top of the Linux kernel and the Hardware Abstraction Layer (HAL). This component connects the application layer to the lower-level system components, enabling high-performance applications to take advantage of hardware.
Android’s Native Libraries Layer consists of C/C++ libraries that provide access to low-level system functionality like graphics rendering, audio processing, and networking. Those libraries are essential for applications requiring high performance.
Some examples of native libraries in Android include OpenGL ES for graphics rendering, OpenSL ES for audio processing, and libcurl for networking. Additionally, you can create your own native libraries.
Native libraries in Android must be written in C/C++ and compiled using the Android Native Development Kit (NDK).
Native libraries provide significant performance improvements over Java-based code in Android.
Android Runtime Layer (ART)
An important layer in Android architecture, the Android Runtime (ART) sits above the Linux kernel and below the Application Framework.
The Java or Kotlin programming languages are used for executing and managing application code.
ART replaces the earlier Dalvik runtime used by earlier Android versions.
There is one major difference between the two runtimes: ART uses an Ahead-Of-Time (AOT) compiler, while Dalvik uses a Just-In-Time (JIT) compiler.
During JIT compilation, the code is compiled on-demand at runtime, while during AOT compilation, the code is compiled during installation. As a result, the compiled code can be executed directly by the system without any further processing, resulting in faster startup times and better performance in ART.
It also includes a garbage collector, which manages memory allocation and deallocation automatically. ART also optimizes the performance of applications through runtime profiling.
Application Framework Layer:
The Application Framework layer sits on top of the Native Libraries layer in the Android architecture.
It enables you to easily build rich, interactive applications using high-level services and APIs.
Application Framework consists of the following components:
| Components | Overview |
| Activity Manager | This component manages the lifecycle of applications and user interactions with them, including activities, services, broadcasts, and other components. |
| Content Providers | This allows apps to share data with each other and with the system, allowing data to be stored centrally and accessed by other applications. |
| Resource Manager | Manages non-code resources such as graphics, strings, and layouts. |
| Notification Manager | This allows applications to display alerts, notifications, and messages to users. |
| View System | Provides layouts, widgets, and other components required to develop user interfaces. |
| Package Manager | Manages the installation, removal, upgrading, and security permissions of applications. |
| Telephony Manager | Accesses information and services related to telephony, such as making phone calls, sending SMS messages, and monitoring network connectivity. |
| Location Manager | It offers location-based services, such as GPS tracking and geocoding. |
| Content Manager | This tool allows you to access contacts, events, and media files. |
Application Framework simplifies Android application development by providing a rich set of APIs and services, allowing you to focus on creating great user experiences without worrying about system details.
Applications Layer
In Android architecture, the application layer is the topmost layer, where users can interact with their devices through pre-installed or downloaded applications.
It provides a framework for developers to build user-friendly, responsive, and secure applications that run seamlessly on various Android devices.
The applications layer comprises several key components, including:
| Components | Overview |
| Activities | Activities represent the application’s user interface. An activity consists of a single screen with a user interface. For example, an email application might have an activity for composing email messages. Additionally, it might have an inbox view and a message details view. |
| Services | Services run in the background and take care of long-running processes or tasks. While they have no user interface, they can interact with other components, such as activities and broadcast receivers. |
| Broadcast receivers | They listen for system-wide events, like incoming phone calls, low battery warnings, and changes in network connectivity. |
| Content providers | They manage access to shared application data. Their purpose is to provide an interface for storing, retrieving, and sharing data across applications in a standard manner. |
In conclusion, understanding the architecture of Android is essential for you as an Android developer to build high-quality applications. Android architecture is designed to provide a stable and scalable platform for building mobile applications, with support for a wide range of programming languages and development tools. By comprehending the Android architecture, you can develop applications that are efficient, stable, and easy to maintain.
