Access and modify a variable from inner anonymous class

Question

I have the following code:

boolean gameSuccess = false;
@Override
    public boolean saveMission(final Mission mission) {
        realm = Realm.getInstance(realmConfiguration);

        realm.executeTransactionAsync(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                realm.copyToRealm(mission);
            }
        }, new Realm.Transaction.OnSuccess() {
            @Override
            public void onSuccess() {
                Log.d(TAG, "onSuccess: mission saved");
                realm.close();
                missionSuccess = true;
            }
        }, new Realm.Transaction.OnError() {
            @Override
            public void onError(Throwable error) {
                Log.d(TAG, "onError: mission failed");
                realm.close();
                missionSuccess = false;
            }
        });
        return gameSuccess;
    }

gameSuccess is always false even if onSuccess was called. What is the way to get this done?

Answer 1

Async isn't blocking, so your code is wrong. The transaction doesn't happen before the return, but any unspecified time later, which is why it is always false.

You either need to provide a callback to your method or convert the transaction to blocking

public void saveMission(final Mission mission, Callback callback) {
     realm.executeTransactionAsync(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                realm.copyToRealm(mission);
            }
        }, new Realm.Transaction.OnSuccess() {
            @Override
            public void onSuccess() {
                Log.d(TAG, "onSuccess: mission saved");
                realm.close(); 
                callback.onSuccess();
            }
        }, new Realm.Transaction.OnError() {
            @Override
            public void onError(Throwable error) {
                Log.d(TAG, "onError: mission failed");
                realm.close();
                callback.onError();
            }
        });
}

or

realm.executeTransaction(...)