Enable Multidex in Android Application

What is multidex file and why we need for the APK file?

Android application (APK) files contain executable bytecode files in the form of Dalvik Executable (DEX) files, which contain the compiled code used to run your app. The Dalvik Executable specification limits the total number of methods that can be referenced within a single DEX file to 65,536, including Android framework methods, library methods, and methods in your own code. Getting past this limit requires that you configure your app build process to generate more than one DEX file, known as a multidex configuration.

How to configure our application for multidex?

If ourminSdkVersion is set to 21 or higher, all we need to do is set multiDexEnabled to true in our module-level build.gradle file, as shown here:

android {
    defaultConfig {
        ...
        minSdkVersion 21 
        targetSdkVersion 26
        multiDexEnabled true
    }
    ...
}

android {

defaultConfig {

...

minSdkVersion 21

targetSdkVersion 26

multiDexEnabled true

}

...

}

however if our min Sdk Version is less than 21 then we need to following two steps to configure multidex.

step 1:- Modify the module-level build.gradle file to enable multidex and add the multidex library as a dependency, as shown here:

android {
    defaultConfig {
        ...
        minSdkVersion 15 
        targetSdkVersion 26
        multiDexEnabled true
    }
    ...
}

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

android {

defaultConfig {

...

minSdkVersion 15

targetSdkVersion 26

multiDexEnabled true

}

...

}

dependencies {

compile 'com.android.support:multidex:1.0.1'

}

step 2:- Depending on whether we override the Application class, perform one of the following:

if we don’t override Application class then we edit our manifest file to set android:name in the <application> tag as follows:

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

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="com.example.myapp">

<application

android:name="android.support.multidex.MultiDexApplication" >

...

</application>

</manifest>

If we do override the Application class, change it to extend MultiDexApplication (if possible) as follows:

public class MyApplication extends MultiDexApplication { ... }

1	public class MyApplication extends MultiDexApplication { ... }

Or if we do override the Application class but it’s not possible to change the base class, then we can instead override theattachBaseContext()method and call MultiDex.install(this) to enable multidex:

public class MyApplication extends SomeOtherApplication {
  @Override
  protected void attachBaseContext(Context base) {
     super.attachBaseContext(base);
     MultiDex.install(this);
  }
}