从 SQLite 和 RecyclerView 中删除项目

Question

我无法从 SQLite 数据库和 RecyclerView 中删除项目。现在我的代码将从 recyclerview 中删除该行，但不会从数据库中删除。关于如何获取适配器位置以转换为从数据库中删除数据的任何提示？

库存.java

public class Inventory extends AppCompatActivity implements RVInterface{

    private AlertDialog.Builder dialogBuilder;
    private AlertDialog dialog;
    private EditText addItemName, addItemQuantity;
    private Button addItemBtn, cancelAddBtn;
    private ImageView settingsButton, deleteItemBtn;
    private InventoryDB DB;
    private RecyclerView recyclerView;
    private ArrayList<String> ids, names, qtys;
    private RVAdapter rvAdapter;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_inventory_database);

        DB = new InventoryDB(this);
        ids = new ArrayList<>();
        names = new ArrayList<>();
        qtys = new ArrayList<>();
        recyclerView = findViewById(R.id.rv_items);
        displayItems();
        rvAdapter = new RVAdapter(this, ids, names, qtys, this);
        recyclerView.setAdapter(rvAdapter);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));


        settingsButton = findViewById(R.id.settingsButton);
        settingsButton.setOnClickListener(view -> {
            Intent intent=new Intent(Inventory.this, SMSAlertScreen.class);
            startActivity(intent);
        });

    }

    private void displayItems() {
        Cursor cursor = DB.getItemsInDB();
        if(cursor.getCount()==0) {
            Toast.makeText(Inventory.this, "No items in inventory database!", Toast.LENGTH_LONG).show();
            return;
        } else {
            while(cursor.moveToNext()) {
                ids.add(cursor.getString(0));
                names.add(cursor.getString(1));
                qtys.add(cursor.getString(2));
            }
        }
    }

    public void addItem(View view) {
        createNewAddItemDialog();
    }

    public void createNewAddItemDialog(){
        dialogBuilder = new AlertDialog.Builder(this);
        final View addItemPopupView = getLayoutInflater().inflate(R.layout.popup_additem, null);
        addItemName = (EditText)  addItemPopupView.findViewById(R.id.additempopup_itemname);
        addItemQuantity = (EditText)  addItemPopupView.findViewById(R.id.additempopup_itemquantity);
        addItemBtn = (Button) addItemPopupView.findViewById(R.id.additempopup_add);
        cancelAddBtn = (Button) addItemPopupView.findViewById(R.id.additempopup_cancel);

        dialogBuilder.setView(addItemPopupView);
        dialog = dialogBuilder.create();
        dialog.show();

        addItemBtn.setOnClickListener(v -> {
            String itemName = addItemName.getText().toString();
            String itemQuantity = addItemQuantity.getText().toString();
            if (itemName.equals("") || itemQuantity.equals("")) {
                //addError.setText("Please ensure both fields are filled out!");
            } else {
                Boolean itemExists = DB.checkItemExists(itemName);
                if (itemExists){
                //addError.setText("Item already exists!");
                } else {
                    DB.addItem(itemName, Integer.parseInt(itemQuantity));
                    rvAdapter.addItem(itemName, itemQuantity);
                    dialog.dismiss();
                    Toast.makeText(Inventory.this, "Item added!", Toast.LENGTH_LONG).show();
                }
            }
        });

        cancelAddBtn.setOnClickListener(v -> dialog.dismiss());
    }

    @Override
    public void onItemClick(int pos) {

    }
}

RVAdapter.java

    private Context context;
    private ArrayList item_id, item_name, item_qty;
    private final RVInterface rvInterface;
    private InventoryDB inventoryDB;



    public RVAdapter(Context context, ArrayList item_id, ArrayList item_name, ArrayList item_qty,
                     RVInterface rvInterface) {
        this.context = context;
        this.item_id = item_id;
        this.item_name = item_name;
        this.item_qty = item_qty;
        this.rvInterface = rvInterface;
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(context).inflate(R.layout.inventory_row,parent,false);
        return new MyViewHolder(v, inventoryDB).linkAdapter(this);
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
        holder.item_id.setText(String.valueOf(item_id.get(position)));
        holder.item_name.setText(String.valueOf(item_name.get(position)));
        holder.item_qty.setText(String.valueOf(item_qty.get(position)));
    }

    @Override
    public int getItemCount() {
        return item_id.size();
    }

    public void addItem(String name, String qty){
        item_id.add(item_id.size() + 1);
        item_name.add(name);
        item_qty.add(qty);
    }

    public void deleteItem(int id, InventoryDB inventoryDB) {
        inventoryDB.deleteItem(id);
    }


    public static class MyViewHolder extends RecyclerView.ViewHolder {
        TextView item_id, item_name, item_qty;
        ImageView item_delete;
        private RVAdapter rvAdapter;
        public MyViewHolder(@NonNull View itemView, InventoryDB inventoryDB) {
            super(itemView);

            item_id = itemView.findViewById(R.id.item_id_text);
            item_name = itemView.findViewById(R.id.item_name_text);
            item_qty = itemView.findViewById(R.id.item_qty_text);
            item_delete = itemView.findViewById(R.id.delete_item_btn);

            item_delete.setOnClickListener(view -> {
                rvAdapter.item_id.remove(getAdapterPosition());
                rvAdapter.item_name.remove(getAdapterPosition());
                rvAdapter.item_qty.remove(getAdapterPosition());
                rvAdapter.notifyItemRemoved(getAdapterPosition());

            });
        }

        public MyViewHolder linkAdapter(RVAdapter rvAdapter){
            this.rvAdapter = rvAdapter;
            return this;
        }
    }
}

库存数据库.java

public class InventoryDB extends SQLiteOpenHelper{

    private static final String DATABASE_NAME = "inventory.db";
    private static final int VERSION = 1;

    public InventoryDB(Context context) {
        super(context, DATABASE_NAME, null, VERSION);
    }

    private static final class InventoryTable {
        private static final String TABLE = "inventory";
        private static final String COL_ID = "_id";
        private static final String COL_ITEM = "item";
        private static final String COL_QTY = "quantity";
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table " + InventoryTable.TABLE + " (" +
                InventoryTable.COL_ID + " integer primary key autoincrement, " +
                InventoryTable.COL_ITEM + " text, " +
                InventoryTable.COL_QTY + " integer " + ")");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion,
                          int newVersion) {
        db.execSQL("drop table if exists " + InventoryDB.InventoryTable.TABLE);
        onCreate(db);
    }

    public Boolean checkForData() {
        SQLiteDatabase db = getWritableDatabase();
        Cursor cursor = db.rawQuery("select * from " + DATABASE_NAME, null);

        if (cursor.moveToFirst())
            return true;
        else
            return false;
    }

    public Boolean checkItemExists(String item) {
        SQLiteDatabase db = getWritableDatabase();

        Cursor cursor = db.rawQuery("Select * from inventory where item =?", new String[] {item});
        if (cursor.getCount() > 0)
            return true;
        else
            return false;
    }

    public void addItem(String item, int qty) {
        SQLiteDatabase db = getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(InventoryDB.InventoryTable.COL_ITEM, item);
        values.put(InventoryDB.InventoryTable.COL_QTY, qty);

        long result = db.insert(InventoryDB.InventoryTable.TABLE, null, values);
        if (result == -1) {
            //failed
        } else {
            //added
        }
    }

    public Boolean editItem(String item, int qty) {
        SQLiteDatabase db = getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(InventoryTable.COL_QTY, qty);
        Cursor cursor = db.rawQuery("select * from " + InventoryTable.TABLE + " where item = ?", new String[]{item});
        if(cursor.getCount()>0){
            long result = db.update(InventoryTable.TABLE, values, "item=?", new String[]{item});
            if (result == -1){
                return false;
            } else {
                return true;
            }
        } else {
            return false;
        }

    }

    public Boolean deleteItem(int id) {
        SQLiteDatabase db = getWritableDatabase();

        Cursor cursor = db.rawQuery("Select * from inventory where id = ?", new String[] { String.valueOf(id) });
        if (cursor.getCount() > 0) {
            db.delete(InventoryTable.TABLE, InventoryTable.COL_ID + " = ?", new String[]{ String.valueOf(id) });
            return true;
        } else {
            return false;
        }
    }


    public Cursor getItemsInDB() {
        SQLiteDatabase db = getWritableDatabase();
        Cursor cursor = db.rawQuery("select * from inventory", null);
        return cursor;
    }
}