我正在学习 mvvm 结构，并使用 mvvm 结构制作了一个应用程序。我也用过房间RxJava。
代码
public class ScoresActivity extends AppCompatActivity {
RecyclerView recyclerView;
List<ScoreDataViewModel> scoreDataViewModelList;
ScoreAdapter scoreAdapter;
ScoreViewModel scoreViewModel;
private final CompositeDisposable mDisposable = new CompositeDisposable();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_scores);
init();
}
private void init() {
recyclerView=(RecyclerView)findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
scoreDataViewModelList=new ArrayList<>();
scoreAdapter=new ScoreAdapter(scoreDataViewModelList);
recyclerView.setAdapter(scoreAdapter);
ScoreViewModelFactory scoreViewModelFactory = Injection.provideScoreViewModelFactory(this);
scoreViewModel= ViewModelProviders.of(this,scoreViewModelFactory).get(ScoreViewModel.class);
}
@Override
protected void onStart() {
super.onStart();
mDisposable.add(scoreViewModel.getScoreDataViewModels()
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.subscribe(new Consumer<List<ScoreDataViewModel>>() {
@Override
public void accept(List<ScoreDataViewModel> scoreDataViewModels) throws Exception {
scoreDataViewModelList=scoreDataViewModels;
System.out.println(scoreDataViewModelList.toString());
Log.e("size", String.valueOf(scoreDataViewModelList));
}
}, new Consumer<Throwable>() {
@Override
public void accept(Throwable throwable) throws Exception {
Log.e("Unable to update list", throwable.toString());
}
}));
}
}
在这里，我可以看到日志中打印的大小是正确的。但我在这里看不到项目。
活动分数
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.sevenbits.android.mvvmsample.view.ScoresActivity">
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintLeft_toLeftOf="parent">
</android.support.v7.widget.RecyclerView>
</android.support.constraint.ConstraintLayout>
现在，ScoreViewModel
public class ScoreViewModel extends ViewModel {
private UserDataSource userDataSource;
List<ScoreDataViewModel> scoreDataViewModelList;
public ScoreViewModel(UserDataSource userDataSource) {
this.userDataSource = userDataSource;
}
public Flowable<List<ScoreDataViewModel>> getScoreDataViewModels() {
return userDataSource.getUsers().map(new Function<List<User>, List<ScoreDataViewModel>>() {
@Override
public List<ScoreDataViewModel> apply(List<User> users) throws Exception {
List<ScoreDataViewModel> scoreDataViewModels = new ArrayList<ScoreDataViewModel>();
for (User user : users) {
scoreDataViewModels.add(new ScoreDataViewModel(user));
}
return scoreDataViewModels;
}
});
}
}
和ScoreAdapter
public class ScoreAdapter extends RecyclerView.Adapter<ScoreViewHolder> {
public List<ScoreDataViewModel> scores;
public ScoreAdapter(List<ScoreDataViewModel> scores) {
this.scores = scores;
}
@Override
public ScoreViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater layoutInflater = LayoutInflater.from(parent.getContext());
ItemScoreBinding itemScoreBinding = ItemScoreBinding.inflate(layoutInflater, parent, false);
return new ScoreViewHolder(itemScoreBinding);
}
@Override
public void onBindViewHolder(ScoreViewHolder holder, int position) {
ScoreDataViewModel scoreDataViewModel = scores.get(position);
holder.bind(scoreDataViewModel);
}
@Override
public int getItemCount() {
return scores.size();
}
}
视图持有者
public class ScoreViewHolder extends RecyclerView.ViewHolder {
ItemScoreBinding itemScoreBinding;
ScoreViewHolder(ItemScoreBinding itemScoreBinding) {
super(itemScoreBinding.getRoot());
this.itemScoreBinding=itemScoreBinding;
}
void bind(ScoreDataViewModel scoreDataViewModel) {
itemScoreBinding.setScoreViewModel(scoreDataViewModel);
}
}
现在，我的问题是为什么我看不到 recyclerview 项目。当我在不使用空间的情况下设置数据时，它非常有效（不从数据库中获取数据，而是静态地创建和添加 ScoreDataViewModel 对象）。我哪里做错了？或者我这样做的方式是错误的？请帮助我，因为我对房间、rxjava 和 mvvm 完全陌生。
如果您提出要求，我还可以编辑问题并添加更多信息。请帮我。
注意：scoreAdapter.notifyDataSetChanged()方法不起作用。