Search⌘ K
AI Features
Home
Courses
Modern Android App Development with Java

Room Database

Discover how to implement Room database for offline support in your Travel Blog app. Learn to define entities, create DAOs, and build a database with Room annotations. This lesson guides you to efficiently store and manage app data locally while understanding best practices like singleton patterns.

We'll cover the following...

Dependencies

To use the Room database, we need to add it to our dependencies list:

Scheme
dependencies {
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'androidx.swiperefreshlayout:swiperefreshlayout:1.0.0'
    implementation 'com.google.android.material:material:1.1.0-alpha10'
    implementation 'com.github.bumptech.glide:glide:4.10.0'
    implementation 'com.squareup.okhttp3:okhttp:4.2.1'
    implementation 'com.google.code.gson:gson:2.8.6'
    def room_version = "2.2.3"
    implementation "androidx.room:room-runtime:$room_version"
    annotationProcessor "androidx.room:room-compiler:$room_version"
}

Because Room database heavily relies on custom annotations, we also added Room annotationProcessor dependency.

Entities

Now, we need to tell Room what entities we want to save to the database. Let’s open the Blog class and add the @Entity annotation (1). Doing so, we tell the Room to create a table for the blog entity.

To define a primary key we can simply use @PrimaryKey annotation on the id field (2). While the Room library can automatically persist all Java primitives, it can’t persist custom objects, like ...