Belajar Android bagian 2 (Arsitektur Android & Application Building Blocks)

Summary

This tutorial covers the architecture of Android applications, starting with the Linux kernel that supports hardware interactions like display and memory management. The native libraries in C/C++ provide essential services, while the Android Runtime, including the Dalvik Virtual Machine and core libraries, enables efficient application execution. The Application Framework provides key tools like Activity Manager and Content Provider for app development, facilitating data sharing and component communication. Key Android components like Activities, Content Providers, Services, and Intents are explained, showcasing how they work together to create a functional Android app.

Takeaways

• 😀 Android is an open-source platform for mobile application development, built on the Linux kernel.
• 😀 The Linux kernel handles hardware operations such as display, memory, and power management for Android devices.
• 😀 Native libraries (written in C and C++) provide essential services for Android applications, such as graphics rendering and multimedia support.
• 😀 Android uses the Dalvik Virtual Machine (DVM) to run optimized bytecode (.dex files) for better processor efficiency on limited resources like battery and memory.
• 😀 The core libraries of Android, written in Java, provide essential functionalities for application development, including I/O operations and utilities.
• 😀 The application framework offers services like activity management, window management, and content sharing between applications through content providers.
• 😀 An Android activity can be seen as a window that manages user interaction with the application. Only one activity is on top at a time.
• 😀 Content providers enable data sharing between applications, such as sharing contacts from a contact app to other apps.
• 😀 Services in Android run in the background without a user interface, handling tasks like email notifications or media playback without direct interaction.
• 😀 Intents in Android are used for communication between components, such as passing data between activities or requesting actions from services.

Q & A

What is the Linux kernel's role in Android architecture?

The Linux kernel in Android handles essential hardware functions, such as display, keyboard, driver management, memory, audio, and power management. It is chosen because of its reliability and ability to support these system requirements.

What is the purpose of the native libraries in Android?

The native libraries in Android, written in C and C++, provide crucial services for applications above them. These services include graphics rendering (via OpenGL and SGL), media management, font rendering (via FreeType), and database management (via SQLite).

What is the role of the Android Runtime (ART)?

The Android Runtime (ART) is responsible for executing Android applications. It consists of two key components: the Dalvik Virtual Machine, which runs optimized bytecode, and the core libraries, which provide essential Java-based services.

How does the Dalvik Virtual Machine work in Android?

The Dalvik Virtual Machine executes files with the .dex extension, which are optimized bytecode versions of Java code. The bytecode from Java (.class files) is compiled into .dex files to improve processor efficiency, making it suitable for Android's limited battery and memory constraints.

What are core libraries in Android and how are they used?

Core libraries in Android are written in Java and provide necessary utilities for input/output operations, system functions, and other key services required for the system to run. They are part of the Android Runtime, enabling the application framework to function properly.

What is the function of the application framework in Android?

The application framework provides essential APIs for developers to create Android applications. It includes various managers like Activity Manager, Package Manager, Telephony Manager, and others that help in managing activities, resources, and services across the system.

What is an Activity in Android?

An Activity in Android represents a single screen or window within the app. It can be thought of as a page that displays user interface elements. An app can have multiple activities, but only one can be on top at a time, such as viewing an email list or reading an individual email.

What is a Content Provider in Android?

A Content Provider allows applications to share data with other applications. For example, the contacts app might provide a content provider to enable other apps to access or modify contact information, while maintaining data consistency.

How do Services work in Android?

Services in Android run in the background without a user interface. They perform tasks like handling email notifications or playing music in the background. Services can operate independently of the app’s user interface and provide ongoing functionality.

What is the role of Intents in Android?

Intents in Android serve as a communication mechanism between different components of an app. They allow components to pass data to each other, such as sending data between activities, enabling them to interact and communicate.