Ditto Android Kotlin Quickstart App 🚀

Prerequisites

After you have completed the common prerequisites you will need the following:

• Android Studio Ladybug or newer

Permissions (already configured)

• https://docs.ditto.live/install-guides/kotlin/android-permissions

Documentation

• Kotlin Install Guide
• Kotlin API Reference
• Kotlin SDK Release Notes

Building and Running the Android Application

Assuming you have Android Studio and other prerequisites installed, you can build and run the app by following these steps:

1. Create an application at https://portal.ditto.live/. Make note of the app ID and online playground token.
2. Copy the .env.sample file at the top level of the quickstart repo to .env and add your App ID, Online Playground Token, Auth URL, and Websocket URL.
3. Launch Android Studio and open the quickstart/android-kotlin directory.
4. In Android Studio, select a connected Android device, or create and launch an Android emulator and select it as the destination, then choose the Run > Run 'app' menu item.

The app will build and run on the selected device or emulator. You can add, edit, and delete tasks in the app.

If you run the app on additional devices or emulators, the data will be synced between them.

Compatible with Android Automotive OS (AAOS)

A Guided Tour of the Android App Source Code

The Android app is a simple to-do list app that demonstrates how to use the Ditto Android SDK to sync data with other devices. It is implemented using Kotlin and Jetpack Compose, which is a modern toolkit for building native Android UI.

It is assumed that the reader is familiar with Android development and with Compose, but needs some guidance on how to use Ditto. The following is a summary of the key parts of integration with Ditto.

Adding the Ditto SDK

At the bottom of app/build.gradle.kts, you will see this line that causes Android Studio to automatically download the Ditto SDK from Maven Central and add it to the project:

    implementation("live.ditto:ditto:4.8.2")

To use a newer version of the SDK, change the version number in this line.

Initializing Ditto

In app/src/main/java/live/ditto/quickstart/tasks/TasksApplication.kt, you will see the TasksApplication class. This class is a subclass of Application. Its onCreate() method, which is called by the system when the app is launched, calls setupDitto(), which gets application ID and online playground token from the build configuration and uses it to create an instance of the Ditto class which is stored in a singleton object of the DittoHandler class.

Other classes import live.ditto.quickstart.tasks.DittoHandler.Companion.ditto to access the singleton Ditto instance.

The Task Data Model

The task data model is implemented as a Kotlin data class in app/src/main/java/live/ditto/quickstart/tasks/data/Task.kt. This class has properties _id, title, done, and deleted. The _id property is a unique identifier for the task, and the deleted property is used to mark tasks that have been deleted but are still present in the store.

This class has a fromJson() method that can be used to convert the JSON data returned by the Ditto store into a Task object, which can then be used by Kotlin code.

The Tasks List

The main screen is a list of all tasks. This is implemented in app/src/main/java/live/ditto/quickstart/tasks/list/TasksListScreen.kt. The associated view model is in app/src/main/java/live/ditto/quickstart/tasks/list/TasksListScreenViewModel.kt, which is where all the code is for retrieving data from the Ditto store and converting it into objects that can be displayed onscreen.

The Edit Screen

The edit screen allows the user to enter a new task or to edit an existing task. It is implemented in app/src/main/java/live/ditto/quickstart/tasks/list/edit/EditScreen.kt. The associated view model is in app/src/main/java/live/ditto/quickstart/tasks/list/edit/EditScreenViewModel.kt, and this contains the associated code for manipulating data in the Ditto store.