Realm - Realm.init(this) failed in onCreate?

Question

I put Realm.init(this) in the onCreate of my Application class.

But it throws an exception while I'm calling Realm.getDefaultInstance() in the onCreate of my Activity.

    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2511)
    at android.app.ActivityThread.-wrap11(ActivityThread.java)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1360)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:148)
    at android.app.ActivityThread.main(ActivityThread.java:5480)
    at java.lang.reflect.Method.invoke(Method.java)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.IllegalStateException: Call `Realm.init(Context)` before calling this method.
    at io.realm.Realm.getDefaultInstance(Realm.java:208)
    at com.kimi.fastdb.PrefActivity.getRealmHelper(PrefActivity.java:1724)
    at com.kimi.fastdb.PrefActivity.onCreate(PrefActivity.java:270)
    at com.kimi.fastdb.LauncherActivity.onCreate(LauncherActivity.java:464)
    at android.app.Activity.performCreate(Activity.java:6308)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2400)

Why the realm instance not been initialized after my Application starts? And how to fix it?

Application:

public class App extends MultiDexApplication {

    @Override
    public void onCreate() {
        super.onCreate();
        Realm.init(this);
        RealmConfiguration realmConfiguration = new RealmConfiguration.Builder()
                    .schemaVersion( REALM_DATABASE_VERSION ) // Must be bumped when the schema changes
                    .migration( migration ) // Migration to run instead of throwing an exception
        //          .deleteRealmIfMigrationNeeded()
                    .build();
        Realm.compactRealm( realmConfiguration );
        Realm.setDefaultConfiguration(realmConfiguration);

    }
    ...
}

AndroidManifest.xml

<application
            android:name=".App"
            android:allowBackup="true"
            android:allowClearUserData="true"
            android:allowTaskReparenting="false"
            android:hardwareAccelerated="true"
            android:icon="@mipmap/ic_launcher"
            android:label="@string/app_name"
            android:largeHeap="true"
            android:theme="@style/SplashScreenTheme">
...

</application>

Answer 1

Try :

Realm.init(getApplicationContext());
Realm realm = Realm.getDefaultInstance();

If you have specific configuration :

Realm.init(getApplicationContext());
Realm realm = Realm.getInstance(RealmConfiguration yourConfg);

After that, you can begin transaction and commit it.