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Gradle Plugin

The JetStart Gradle plugin (com.jetstart.hot-reload) is responsible for integrating JetStart's hot-reload capabilities into your Android application's build process.

Overview​

The Gradle plugin automates several key tasks:

  1. BuildConfig Injection - It adds JETSTART_SERVER_URL and JETSTART_SESSION_ID fields to your app's BuildConfig. These fields are dynamically updated by jetstart dev to point to the current development session.
  2. Hot Reload Instrumentation - It configures the debug build variant to support DEX hot-swapping.
  3. Dependency Management - It ensures that the necessary hot-reload runtime libraries are correctly included in the debug build.

Installation​

The plugin is automatically included when you create a new project with jetstart create. It is applied in your app-level build.gradle:

plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
    // ...
    id 'com.jetstart.hot-reload' version '1.0.0'
}

How It Works​

During a jetstart dev session, the CLI communicates with the Gradle plugin to inject the necessary connection details. This allows the mobile app to automatically discover and connect to the development server without manual configuration.

Injected Fields​

In your MainActivity.kt, you can access these fields to connect to the hot-reload server:

if (BuildConfig.DEBUG) {
    val serverUrl = BuildConfig.JETSTART_SERVER_URL
    val sessionId = BuildConfig.JETSTART_SESSION_ID
    HotReload.connect(this, serverUrl, sessionId)
}

Security​

The Gradle plugin is designed to be active only in debug builds. When you run a release build (jetstart build --release), the plugin:

  • Does not inject any development credentials.
  • Ensures that the hot-reload runtime is not included in the final production binary.
  • Strips any BuildConfig fields related to JetStart.

Configuration​

Most configuration is handled automatically by the JetStart CLI. However, you can see the plugin's impact in your project's build.gradle and gradle.properties.