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.

Get started

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

• Install the SDK
• Import the SDK
• Initialize the client
• Evaluate a flag

Install the SDK

First, declare a dependency on the LaunchDarkly Android SDK:

implementation 'com.launchdarkly:launchdarkly-android-client-sdk:5.0.0'
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The SDK uses AndroidX from Jetpack. If your project does not use AndroidX, read Android's migration guide.

Import the SDK

Next, import the LaunchDarkly client in your application code:

import com.launchdarkly.sdk.*;
import com.launchdarkly.sdk.android.*;
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Initialize the client

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.

We recommend calling the client initialization method with a timeout of zero seconds. This 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 connects in the background and continually updates itself with the latest flags.

Here's how to create the client:

LDConfig ldConfig = new LDConfig.Builder(AutoEnvAttributes.Enabled)
    .mobileKey("mobile-key-123abc")
    .build();
LDContext context = LDContext.create("context-key-123abc");
LDClient client = LDClient.init(this.getApplication(), ldConfig, context, 0);
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If you need to, you can block for a short period of time until the SDK retrieves the latest feature flags from LaunchDarkly by using a non-zero value for the timeout parameter in the initialization call. However, calling blocking code from the main thread in an Android app is not a best practice, and we do not recommend it. Blocking until the SDK retrieves the latest feature flags from LaunchDarkly will cause your app never to load if there is a connectivity problem. If you must use a non-zero timeout parameter, we recommend setting it for five seconds or fewer.

To learn more about the specific configuration options available in this SDK, read LDConfig.Builder.

Evaluate a flag

After you create the client, you can use it to check which variation a particular context 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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Shut down the client

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 contexts exceeds a limit. When you call identify, the number of cached contexts increments. Eventually, the number of cached contexts exceeds maxCachedContexts. When that happens, the SDK deletes context data in excess of maxCachedContext, starting with the oldest context first.

Supported features

This SDK supports the following features:

• Anonymous contexts and users
• Automatic environment attributes
• Configuration, including
  • Application metadata configuration
  • Service endpoint configuration
• Context configuration
• Evaluating flags
• Flag evaluation reasons
• Flushing events
• Getting all flags
• Identifying and changing contexts
• Logging configuration
• Monitoring SDK status
• Multiple environments
• Offline mode
• Private attributes
• Relay Proxy configuration, using proxy mode
• Sending custom events
• Shutting down
• Subscribing to flag changes