通过检查光标是否为空来设置 textview 和 recycleview 的可见性

Question

我正在尝试添加消息说没有数据并且从游标获取数据的回收视图为空我尝试了很多解决方案但没有任何效果这是主要活动：public class MainActivity extends AppCompatActivity implements        LoaderManager.LoaderCallbacks<Cursor> {    private static final String TAG = MainActivity.class.getSimpleName();    private static final int INVENTORY_LOADER_ID = 0;    private CursorAdapter mAdapter;    RecyclerView mRecyclerView;    TextView emptyList;    Cursor inventoryData;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mRecyclerView = (RecyclerView) findViewById(R.id.inventories);        emptyList = (TextView) findViewById(R.id.empty_list);        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));        mAdapter = new CursorAdapter(this, this, this);        mRecyclerView.setAdapter(mAdapter);        getSupportLoaderManager().initLoader(INVENTORY_LOADER_ID, null, this);    }    @Override    protected void onResume() {        super.onResume();        getSupportLoaderManager().restartLoader(INVENTORY_LOADER_ID, null, this);    }    @Override    public Loader<Cursor> onCreateLoader(int id, final Bundle loaderArgs) {        return new AsyncTaskLoader<Cursor>(this) {            Cursor inventoryData = null;            @Override            protected void onStartLoading() {                if (inventoryData != null) {                    emptyList.setVisibility(View.GONE);                    deliverResult(inventoryData);                } else  {                    forceLoad();                }        }

Answer 1

检查游标是否“有效”的方法是

((cursor != null) && (cursor.getCount() > 0))