1.表格

view 中获取数据

final ProductListViewModel viewModel =
               ViewModelProviders.of(this).get(ProductListViewModel.class);

       viewModel.getProducts().observe(this, new Observer<List<ProductEntity>>() {
            @Override
            public void onChanged(@Nullable List<ProductEntity> myProducts) {
                if (myProducts != null) {
                    mBinding.setIsLoading(false);
                    mProductAdapter.setProductList(myProducts);
                } else {
                    mBinding.setIsLoading(true);
                }
            }
        });

//BasicRxJavaSample:
//得到 ViewModelFactory
public static ViewModelFactory provideViewModelFactory(Context context) {
        UserDataSource dataSource = provideUserDataSource(context);
        return new ViewModelFactory(dataSource);
}

//得到 factory 实例
mViewModelFactory = Injection.provideViewModelFactory(this);

//使用ViewModelProviders获取 viewModel 实例
mViewModel = ViewModelProviders.of(this, mViewModelFactory).get(UserViewModel.class);

//使用 RxJava 读取数据库
  mDisposable.add(mViewModel.getUserName()
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(new Consumer<String>() {
          @Override
          public void accept(String userName) throws Exception {
            mUserName.setText(userName);
          }
        }, new Consumer<Throwable>() {
          @Override
          public void accept(Throwable throwable) throws Exception {
            Log.e(TAG, "Unable to update username", throwable);
          }
        }));