In order to enable a multidex configuration you need:

• to change your Gradle build configuration
• to use a MultiDexApplication or enable the MultiDex in your Application class

Gradle configuration

In app/build.gradle add these parts:

android {
    compileSdkVersion 24
    buildToolsVersion "24.0.1"

    defaultConfig {
        ...
        minSdkVersion 14
        targetSdkVersion 24
        ...

        // Enabling multidex support.
        multiDexEnabled true
    }
    ...
}

dependencies {
  compile 'com.android.support:multidex:1.0.1'
}

Enable MultiDex in your Application

Then proceed with one of three options:

• Multidex by extending Application

• Multidex by extending MultiDexApplication

• Multidex by using MultiDexApplication directly

When these configuration settings are added to an app, the Android build tools construct a primary dex (classes.dex) and supporting (classes2.dex, classes3.dex) as needed.
The build system will then package them into an APK file for distribution.

Use this option if you don't need an Application subclass.

This is the simplest option, but this way you can't provide your own Application subclass. If an Application subclass is needed, you will have to switch to one of the other options to do so.

For this option, simply specify the fully-qualified class name android.support.multidex.MultiDexApplication for the android:name property of the application tag in the AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.android.multidex.myapplication">
    <application
        ...
        android:name="android.support.multidex.MultiDexApplication">
        ...
    </application>
</manifest>

Use this option if your project requires an Application subclass.

Specify this Application subclass using the android:name property in the manifest file inside the application tag.

In the Application subclass, add the attachBaseContext() method override, and in that method call MultiDex.install():

package com.example;

import android.app.Application;
import android.content.Context;

/**
 * Extended application that support multidex 
 */
public class MyApplication extends Application {

    @Override
    protected void attachBaseContext(Context base) {
        super.attachBaseContext(base);
        MultiDex.install(this);
    }
}

Ensure that the Application subclass is specified in the application tag of your AndroidManifest.xml:

<application
    android:name="com.example.MyApplication"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name">
</application>

The dexcount plugin counts methods and class resource count after a successful build.

Add the plugin in the app/build.gradle:

apply plugin: 'com.android.application'

buildscript {
    repositories {
        mavenCentral() // or jcenter()
    }

    dependencies {
        classpath 'com.getkeepsafe.dexcount:dexcount-gradle-plugin:0.5.5'
    }
}

Apply the plugin in the app/build.gradle file:

apply plugin: 'com.getkeepsafe.dexcount'

Look for the output data generated by the plugin in:

../app/build/outputs/dexcount

Especially useful is the .html chart in:

../app/build/outputs/dexcount/debugChart/index.html

This is very similar to using an Application subclass and overriding the attachBaseContext() method.

However, using this method, you don't need to override attachBaseContext() as this is already done in the MultiDexApplication superclass.

Extend MultiDexApplication instead of Application:

package com.example;

import android.support.multidex.MultiDexApplication;
import android.content.Context;

/**
 * Extended MultiDexApplication 
 */
public class MyApplication extends MultiDexApplication {

     // No need to override attachBaseContext()

     //..........
}

Add this class to your AndroidManifest.xml exactly as if you were extending Application:

<application
    android:name="com.example.MyApplication"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name">
</application>