数据更新后未通知观察者

Question

我目前正在使用MVVM和RxJava 2开发一个小示例应用程序。

您可以在下面的代码中看到，我使用一个Observable将数据从模型流传输到视图（活动），但是在更新数据时，观察者（活动）从未收到有关更新的通知。只有在第一次检索数据时，才会通知观察者。

ModelRepository

/**
 * This will simulate a data repository that could retrieve data
 * from local or network providers in an actual implementation.
 * <p>
 * This repository is only implemented as Singleton for simulation reasons.
 */
public class NamePairRepository {

    private static final String[] firstNames = {"Kathrin", "Carl", "Denise", "Albert", "Melanie", "Tom"};
    private static final String[] lastNames = {"Smith", "Jordan", "Sarkozy", "McDonald", "Pillepalle", "Bacon"};

    private static NamePairRepository instance = null;

    public static NamePairRepository getInstance() {
        if (instance == null) {
            instance = new NamePairRepository();
        }
        return instance;
    }

    private NamePair namePair;

    private Random random = new Random();

    private NamePairRepository() {
        namePair = new NamePair(firstNames[0], lastNames[0]);
    }

    public Observable<NamePair> getNamePair() {
        return Observable.just(namePair);
    }

    public void updateFirstName() {
        new Handler().postDelayed(() ->
                        namePair.setFirstName(firstNames[random.nextInt(firstNames.length)]),
                1000);
    }

    public void updateLastName() {
        new Handler().postDelayed(() ->
                        namePair.setLastName(lastNames[random.nextInt(lastNames.length)]),
                1000);
    }
}

活动

@Override
    protected void onResume() {
        super.onResume();
        compositeDisposable = new CompositeDisposable();
        compositeDisposable.add(viewModel.getNamePair()
        .subscribeOn(Schedulers.computation())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(this::setNames));
    }

    @Override
    protected void onPause() {
        super.onPause();
        compositeDisposable.clear();
    }

不幸的是，我是RxJava的新手，但据我了解，观察者模式，可观察对象应始终将更改通知给观察者，对吧？

请随时结帐该项目：https://github.com/CodeRedDev/Android-Architecture/tree/mvvm