Прямо сейчас я пытаюсь использовать утилиту просмотра с помощью курсора. Я включил движок курсора в свой адаптер переработчика, основываясь на моих исследованиях. У меня нет желания помещать данные базы данных SQLite в массив данных. Сейчас, похоже, мой код правильный, но когда я загружаю приложение, я получаю пустой экран. Может ли кто-нибудь помочь мне увидеть мою ошибку в моем коде?
Вот мой адаптер:
public class PrescriptionRecyclerAdapter extends RecyclerView.Adapter<PrescriptionRecyclerAdapter.ViewHolder> {
private CursorAdapter mCursorAdapter;
private Context mContext;
private ViewHolder holder;
Cursor prescriptionCursor;
public PrescriptionRecyclerAdapter(Context context, Cursor c) {
mContext = context;
prescriptionCursor = c;
mCursorAdapter = new CursorAdapter(mContext, c, 0) {
@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
// Inflate the view here
View v = LayoutInflater.from(context)
.inflate(R.layout.recycle_item, parent, false);
return v;
}
@Override
public void bindView(View view, Context context, Cursor cursor) {
// Extract data from the current store row and column
int nameColumnIndex = cursor.getColumnIndex(PrescriptionContract.PrescriptionEntry.COLUMN_PRESCRIPTION_NAME);
int amountColumnIndex = cursor.getColumnIndex(PrescriptionContract.PrescriptionEntry.COLUMN_PRESCRIPTION_AMOUNT);
int durationColumnIndex = cursor.getColumnIndex(PrescriptionContract.PrescriptionEntry.COLUMN_PRESCRIPTION_FREQUENCY_DURATION);
final int columnIdIndex = cursor.getColumnIndex(PrescriptionContract.PrescriptionEntry._ID);
//Read the store attritubes from the Cursor for the current stores
String name = cursor.getString(nameColumnIndex);
String amount = cursor.getString(amountColumnIndex);
String duration = cursor.getString(durationColumnIndex);
String col = cursor.getString(columnIdIndex);
// Populate fields with extracted properties
holder.prescriptionName.setText(name);
holder.prescriptionAmount.setText(amount);
holder.prescriptionDays.setText(duration);
}
};
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView prescriptionName;
public TextView prescriptionAmount;
public TextView prescriptionDays;
final public Button prescriptionButton;
public ViewHolder(View itemView) {
super(itemView);
// Find fields to populate in inflated template
prescriptionName = (TextView) itemView.findViewById(R.id.name);
prescriptionAmount = (TextView) itemView.findViewById(R.id.amountlist);
prescriptionDays = (TextView) itemView.findViewById(R.id.daysList);
prescriptionButton = itemView.findViewById(R.id.scheduleButton);
}
}
@Override
public int getItemCount() {
return mCursorAdapter.getCount();
}
public Cursor swapCursor(Cursor cursor) {
if (prescriptionCursor == cursor) {
return null;
}
Cursor oldCursor = prescriptionCursor;
this.prescriptionCursor = cursor;
if (cursor != null) {
this.notifyDataSetChanged();
}
return oldCursor;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
// Passing the binding operation to cursor loader
mCursorAdapter.getCursor().moveToPosition(position);
mCursorAdapter.bindView(holder.itemView, mContext, mCursorAdapter.getCursor());
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
// Passing the inflater job to the cursor-adapter
View v = mCursorAdapter.newView(mContext, mCursorAdapter.getCursor(), parent);
holder = new ViewHolder(v);
return holder;
}
}
Вот мой показ.
public class DisplayActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor>{
private static final int PRESCRIPTION_LOADER = 0;
PrescriptionRecyclerAdapter mCursorAdapter;
private RecyclerView.LayoutManager mLayoutManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(DisplayActivity.this, EditorActivity.class);
startActivity(intent);
}
});
RecyclerView prescriptionRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);
mLayoutManager = new LinearLayoutManager(getApplicationContext());
prescriptionRecyclerView.setLayoutManager(mLayoutManager);
mCursorAdapter = new PrescriptionRecyclerAdapter(this, null);
prescriptionRecyclerView.setAdapter(mCursorAdapter);
//Kick off the loader
getLoaderManager().initLoader(PRESCRIPTION_LOADER,null,this);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_display, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// User clicked on a menu option in the app bar overflow menu
switch (item.getItemId()) {
// Respond to a click on the "Delete all entries" menu option
case R.id.action_delete_all_entries:
deleteAllPrescriptions();
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* Helper method to delete all items in the database.
*/
private void deleteAllPrescriptions() {
int rowsDeleted = getContentResolver().delete(PrescriptionEntry.CONTENT_URI, null, null);
Log.v("CatalogActivity", rowsDeleted + " rows deleted from prescription database");
}
@Override
public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
// Since the editor shows all store attributes, define a projection that contains
// all columns from the store table
String[] projection = {
PrescriptionEntry._ID,
PrescriptionEntry.COLUMN_PRESCRIPTION_NAME,
PrescriptionEntry.COLUMN_PRESCRIPTION_AMOUNT,
PrescriptionEntry.COLUMN_PRESCRIPTION_FREQUENCY_HOURS,
PrescriptionEntry.COLUMN_PRESCRIPTION_FREQUENCY_TIMES,
PrescriptionEntry.COLUMN_PRESCRIPTION_FREQUENCY_DURATION,
PrescriptionEntry.COLUMN_PRESCRIPTION_REFILL,
PrescriptionEntry.COLUMN_PRESCRIPTION_EXPIRATION,
PrescriptionEntry.COLUMN_PRESCRIPTION_PHARMACIST_NAME,
PrescriptionEntry.COLUMN_PRESCRIPTION_PHARMACIST_NUMBER,
PrescriptionEntry.COLUMN_PRESCRIPTION_PHYSICIAN_NAME,
PrescriptionEntry.COLUMN_PRESCRIPTION_PHYSICIAN_NUMBER};
// This loader will execute the ContentProvider's query method on a background thread
return new CursorLoader(this, // Parent activity context
PrescriptionEntry.CONTENT_URI, // Query the content URI for the current store
projection, // Columns to include in the resulting Cursor
null, // No selection clause
null, // No selection arguments
null); // Default sort order
}
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
mCursorAdapter.swapCursor(data);
}
@Override
public void onLoaderReset(Loader<Cursor> loader) {
mCursorAdapter.swapCursor(null);
}
}