Adding Multidex to an Android Project

In Android development, the size of an application's DEX (Dalvik Executable) files can sometimes surpass the 65k method reference limit imposed by the Android platform. When this happens, it becomes necessary to enable multidex support to ensure the smooth functioning of the application. This article will guide you through the process of adding multidex to your Android project, offering insights into why multidex is required, how to implement it, and addressing potential challenges along the way.

Understanding the Need for Multidex

The 65k Method Reference Limit

Android apps are primarily built using Java, Kotlin, or a combination of both. Each method in the codebase contributes to the count of method references. Once an app’s methods exceed 65,536, which is the maximum number that can be referenced with a single DEX file, a build error occurs. This limitation arises from the design of the DEX file format used by the Android Runtime (ART) and the Dalvik Virtual Machine.

Why Multidex?

Multidex comes into play as a solution to this issue. It allows an app to have multiple DEX files within the APK, thus bypassing the 65k limit. By enabling multidex, your application gains the capability to contain and reference a higher number of methods, effectively preventing errors related to exceeding the method reference limit.

Implementing Multidex in Your Android Project

Step 1: Update Gradle Configuration

To integrate multidex support into your Android project, begin by updating the build.gradle file. Inside the module-level build.gradle file, add the following dependency in the dependencies block:

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1android {
2    defaultConfig {
3        ...
4        multiDexEnabled true
5    }
6}
7
8dependencies {
9    implementation 'com.android.support:multidex:1.0.3'
10}

Step 2: Update Application Class

Next, update your Application class to override the attachBaseContext method to enable multidex:

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1import android.app.Application;
2import androidx.multidex.MultiDex;
3
4public class MyApplication extends Application {
5    @Override
6    protected void attachBaseContext(Context base) {
7        super.attachBaseContext(base);
8        MultiDex.install(this);
9    }
10}

Step 3: Clean and Rebuild

After making these changes, clean and rebuild your project. This ensures that the multidex configurations are properly applied to your Android application.

Potential Challenges and Troubleshooting

Instant Run Compatibility

If you encounter issues with Instant Run after enabling multidex, you may need to disable Instant Run by navigating to Settings > Build, Execution, Deployment > Instant Run and unchecking the box for Enable Instant Run.

Third-Party Libraries

When using multidex, certain third-party libraries might not be compatible out-of-the-box. In such cases, consider checking the library's documentation for multidex support or look for alternative libraries that are explicitly designed to work with multidex-enabled applications.