Try adding these lines to your build.gradle

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

This will enable multidex mode, which will allow you to exceed the 64k limit. (Read more here)

API below 21

If you're using an API level below 21, then you also need to add the support library

gradle.build:

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

android.manafest

<?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 you use a custom Application class, try using one the of the following

Solution 1

simply override the MultiDexApplication class

public class MyApplication extends MultiDexApplication { ... }

Solution 2

override attachBaseContext and install MultiDex using the install(Application) function

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

You're not doing anything wrong: the Android API for Cloud Firestore is just big. We'll be working on reducing SDK size on the road to GA.

Meanwhile, you need to enable multidex to build if your application is nontrivial.

We actually use very little of com.google.common, so you may be able to say under the 64k method limit by proguarding your application too.

Updating to 11.6.0 fixes this issue