011 Room

Fragment Bindings and Room Database Setup

Introduction to Fragment Bindings

• The lecture will cover fragment bindings, view bindings for other fragments, and the initiation of a Room database.

• The goal is to enable navigation from the art fragment to the API fragment by clicking an image view.

Implementing Navigation

• The instructor discusses creating a binding variable for the art details fragment, which allows interaction with UI elements.

• A click listener is set on the art image view to navigate to the image API fragment using findNavController.

Back Press Handling

• The importance of overriding back press functionality is highlighted; it allows custom actions when users press back.

• An OnBackPressedCallback object is created to manage what happens during back presses, such as popping the back stack.

Room Database Overview

• Introduction to Room as a modern alternative for SQLite operations in Android development, moving away from manual content providers.

Introduction to Room Database in Android

Overview of Room Database

• The speaker introduces the concept of Room, a database library for Android, and suggests consulting the official documentation for beginners.

• Room is part of Android Jetpack and consists of three main components: the Room database, Data Access Objects (DAOs), and entities.

Components of Room

• DAOs serve as an interface between the Room database and entities, facilitating communication for data operations.

• Entities are defined using data classes that represent tables in the database. Key attributes include name, artist name, year (integer), image URL (string), and an auto-generated primary key.

Creating Entities

• The speaker explains how to define entity properties such as name, artistName, year, and imageUrl within a data class.

• The primary key is annotated with @PrimaryKey(autoGenerate = true) to allow automatic ID generation when creating new entries.

Defining DAO Interface

• A new interface called ArtDao is created to define functions for interacting with the database.

• Functions within this interface will be annotated with specific commands like @Insert, @Delete, or @Query to perform various operations on the database.

Implementing DAO Functions

• The speaker emphasizes using suspend functions for asynchronous operations due to potential time-intensive tasks involved in database interactions.

• An example function named insertArt is introduced which utilizes @Insert annotation; conflict strategies can also be specified during insertion.

Additional DAO Operations

• A deleteArt function is defined using @Delete annotation to remove art objects from the database.

• To retrieve data from the database, an observerArts function returns LiveData containing a list of art items. This function uses SQL queries annotated with @Query.

Final Steps: Creating Database Class

Creating a Room Database in Android

Overview of Database Structure

• The database should be defined as an abstract class to enhance its functionality and maintainability. The speaker refers to documentation for clarity on the structure.

• The database will utilize Room, a persistence library in Android, requiring annotation with @Database. Entities must be specified, with "art" being the primary entity represented as a list.

• A version number is assigned to the database; starting at one, it can be incremented (e.g., version two) when changes are made to the schema or entities.

DAO Implementation

• An abstract function will be created within the database class that returns the Data Access Object (DAO), which facilitates interaction with the database.

• The speaker mentions using Hilt for dependency injection later in the process, indicating that this step is not yet implemented but is planned for future development.

Summary of Current Progress