Android SDK reference

Overview

This topic documents how to get started with the Android SDK, and links to reference information on all of the supported features.

Getting started

After you complete the Getting started process, follow these instructions to start using the LaunchDarkly SDK in your Android application.

First, declare a dependency on the LaunchDarkly Android SDK:

implementation 'com.launchdarkly:launchdarkly-android-client-sdk:3.1.1'
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The SDK uses AndroidX from Jetpack. If your project does not use AndroidX, read Android's migration guide.

Next, import the LaunchDarkly client in your application code:

import com.launchdarkly.sdk.*;
import com.launchdarkly.sdk.android.*;
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After you install the SDK, create a single, shared instance of LDClient. To create a client instance, you need your environment's mobile key. This authorizes your application to connect to a particular environment within LaunchDarkly. Your mobile key is available in the Projects tab of your Account settings page.

The following example shows the simplest way to create the client. It will block for up to five seconds until the latest feature flags are retrieved from LaunchDarkly.

Here is how to create the client:

LDConfig ldConfig = new LDConfig.Builder()
    .mobileKey("YOUR_MOBILE_KEY")
    .build();
LDUser user = new LDUser.Builder("user key")
    .email("fake@example.com")
    .build();
LDClient client = LDClient.init(this.getApplication(), ldConfig, user, 5);
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However, calling blocking code from the main thread in an Android app is not a best practice. The preferred method allows you to use the client immediately. The app stores flags from the previous launch on the device and retrieves them for immediate use. The client still connects in the background and continually updates itself with the latest flags.

Here is the preferred method:

LDClient client = LDClient.init(this.getApplication(), ldConfig, user, 0);
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You can use client to check which variation a particular user will receive for a feature flag.

Here's how:

boolean showFeature = client.boolVariation(flagKey, true);
if (showFeature) {
    // Application code to show the feature
}
else {
    // The code to run if the feature is off
}
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Shutting down

Shut down the client when your application terminates. To learn more, read Shutting down.

Data collection

The data collected by the Android SDK persists until the number of cached users exceeds a limit. When you call identify, the number of cached users increments. Eventually, the number of cached users exceeds maxCachedUsers. When that happens, user data in excess of maxCachedUsers is deleted, starting with the oldest user first.

Supported features

This SDK supports the following features:

• Aliasing users
• Configuration
• Evaluating flags
• Flag evaluation reasons
• Flushing events
• Getting all flags
• Identifying and changing users
• Logging configuration
• Monitoring SDK status
• Multiple environments
• Offline mode
• Relay Proxy configuration
• Sending custom events
• Service endpoint configuration
• Shutting down
• Subscribing to flag changes
• User configuration