AndroidManifest.xml

<application
	android:allowBackup="true"
	android:icon="@mipmap/ic_launcher"
	android:label="@string/app_name"
	android:roundIcon="@mipmap/ic_launcher_round"
	android:supportsRtl="true"
	android:theme="@style/AppTheme">
	<meta-data android:name="com.facebook.accountkit.ApplicationName"
		android:value="@string/app_name" />
	<meta-data android:name="com.facebook.sdk.ApplicationId"
		android:value="@string/FACEBOOK_APP_ID" />
	<meta-data android:name="com.facebook.accountkit.ClientToken"
		android:value="@string/ACCOUNT_KIT_CLIENT_TOKEN" />

	<activity
		android:name="com.facebook.accountkit.ui.AccountKitActivity"
		android:theme="@style/AppLoginTheme"
		tools:replace="android:theme">
	</activity>

<resources>
	<style name="AppLoginTheme" parent="Theme.AccountKit"/>
</resources>

import com.facebook.accountkit.AccountKit;
import com.facebook.accountkit.AccessToken;

@Override
Protected void onCreate(Bundle savedInstanceState){
	AccessToken accessToken = AccountKit.getCurrentAccessToken();
	if (accessToken != null){
		launchAccountActivity();
	}
}