An Overview :
Android is the worldÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s most popular mobile operating system, used on billions of devices worldwide. It is an open-source platform developed by Google and designed for use in smartphones, tablets, smartwatches, and other mobile devices.
Android is built on a layered architecture, with each layer performing specific functions to provide a smooth and seamless user experience. One of the key factors that have contributed to the success of Android is its robust architecture. In this article, we will take a deep dive into the architecture of Android, including its components, layers, and subsystems.
Android Architecture Layers
The architecture of Android can be divided into four layers, each of which provides a different level of abstraction.
1. Linux Kernel Layer:
The Linux Kernel layer is the foundation of the Android operating system. It is responsible for managing the low-level hardware resources of the device, such as the CPU, memory, and input/output systems. The Android kernel is based on the Linux kernel, which is an open-source, Unix-like operating system that is widely used on servers, desktops, and other computing devices.
2. Hardware Abstraction Layer (HAL):
The Hardware Abstraction Layer (HAL) is the layer that sits on top of the Linux kernel and provides a standardized interface for hardware vendors to write device drivers. This layer provides a consistent set of APIs that allow Android to interact with the hardware, regardless of the underlying hardware architecture.
3. Native Libraries Layer:
The Native Libraries Layer is a collection of libraries that are written in C and C++, which provide access to the hardware and other system resources. The libraries provide support for multimedia, graphics, and other system-level functions.
4. Application Framework Layer:
The Application Framework Layer is the topmost layer of the Android architecture. It provides a set of higher-level APIs that allow developers to build applications that can run on Android devices. These APIs include functions for managing the user interface, handling user input, managing network connections, and accessing system resources.
Android Architecture Components
Android architecture is made up of several components that work together to provide a seamless user experience. These components include:
An activity is a single screen that the user interacts with. An application can have multiple activities, and each activity can be thought of as a standalone module that performs a specific task. For example, an email application may have activities for composing an email, viewing the inbox, and managing contacts.
A service is a component that runs in the background and performs a long-running task, such as playing music or downloading files. A service does not have a user interface and can run even when the user is not interacting with the application.
3. Broadcast Receivers:
A broadcast receiver is a component that listens for system-wide events, such as incoming phone calls or battery low notifications. When a broadcast receiver detects an event, it can perform a specific action, such as displaying a notification or starting a service.
4. Content Providers:
A content provider is a component that allows applications to share data with each other. Content providers can be thought of as a database that stores data, and other applications can query and modify that data using a standard set of APIs.
Android Architecture Subsystems
Android also has several subsystems that provide additional functionality to the operating system. These subsystems include:
1. Dalvik Virtual Machine:
The Dalvik Virtual Machine (DVM) is a custom virtual machine that was developed specifically for Android. The DVM is responsible for running Android applications and provides a number of benefits over traditional virtual machines, such as lower memory usage and faster startup times.
2. Android Runtime (ART):
The Android Runtime (ART) is a runtime environment that is used to execute Android applications. ART uses a JIT (Just-In-Time) compilation approach to compile code on-the-fly, which improves application performance.
3. Notification Manager:
The Notification Manager is a subsystem that manages notifications on the Android device. When an application generates a notification, the Notification Manager is responsible for
To establish a solid foundation in Android development, it is crucial to gain a basic understanding of its overall architecture.
The Android implementation is based on a software stack architecture consisting of several components, including a Linux kernel, application framework, libraries, runtime environment, and a set of applications. Android Studio serves as the primary building environment for developers to create Android applications in Java or Kotlin and compile them into bytecode.
When the application is installed on a device, Android Runtime (ART) compiles the bytecode into the native format required by the device’s CPU, allowing the application to run efficiently. A significant aspect of the Android architecture is its focus on performance and efficiency, both in terms of application performance and the reusability of application design.
Throughout this article, we have provided a detailed overview of the Android architecture and its various layers, which include the Linux kernel, relevant libraries, Android runtime, application framework, and Android applications. By presenting a few pointers along the way, we hope that this article will help readers navigate the Android architecture without feeling lost.