Question

所以我试图删除十字按钮上的项目。现在，它已从RecyclerView中删除，但是对于SQLite却很疯狂。如果我删除一项，那一切都很好。但是，当我删除几个项目时，正如我所说的，它会变得疯狂，并导致删除的项目无处不在而不删除任何内容。这是我的DataAdapted.java

import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.List;

public class DataAdapter extends RecyclerView.Adapter<DataAdapter.ViewHolder> {

    private LayoutInflater inflater;
    private List<Booking> bookings;
    private String time;
    DBHelper dbHelper;
    SQLiteDatabase dataBase;

    DataAdapter(Context context, List<Booking> bookings) {
        this.bookings = bookings;
        this.inflater = LayoutInflater.from(context);
    }

    @NonNull
    @Override
    public DataAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

        View view = inflater.inflate(R.layout.list_view, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull DataAdapter.ViewHolder holder, int position) {
        Booking booking = bookings.get(position);
        holder.nameView.setText(booking.getName());
        time = booking.getHours() + ":" + booking.getMinutes();
        holder.timeView.setText(time);
    }

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


    public class ViewHolder extends RecyclerView.ViewHolder {
        TextView nameView;
        TextView timeView;
        ImageView crossImage;
        ViewHolder(View view){
            super(view);
            timeView = view.findViewById(R.id.time_view);
            nameView = view.findViewById(R.id.name_view);
            crossImage = view.findViewById(R.id.crossImage);

            crossImage.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    removeAt(getAdapterPosition());
                }
            });
        }
    }
    public void removeAt(int position) {
        bookings.remove(position);
        notifyItemRemoved(position);
        notifyItemRangeChanged(position, bookings.size());

        DBHelper.delete(position);
    }


}

DBHelper.java

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DBHelper extends SQLiteOpenHelper {

    public static final int DATABASE_VERSION = 1;
    public static final String DATABASE_NAME = "bookingsDb";
    public static final String TABLE_BOOKINGS = "bookings";
    public static final String KEY_ID = "_id";
    public static final String KEY_NUMBER = "_numbers";
    public static final String KEY_NAME = "_names";
    public static final String KEY_HOURS = "_hours";
    public static final String KEY_MINUTES = "_minutes";
    public static final String KEY_PHONE= "_phones";
    Context myContext;
    static DBHelper dbHelper;
    static SQLiteDatabase database;


    public DBHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        myContext = context;
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table " + TABLE_BOOKINGS + "("
                + KEY_ID + " integer primary key,"
                + KEY_NUMBER + " integer,"
                + KEY_NAME + " text,"
                + KEY_HOURS + " text,"
                + KEY_MINUTES + " text,"
                + KEY_PHONE + " text" + ")");
        dbHelper = new DBHelper(myContext);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("drop table if exists " + TABLE_BOOKINGS);

        onCreate(db);
    }

    public static void delete(int id){
        database = dbHelper.getWritableDatabase();
        database.delete(TABLE_BOOKINGS, KEY_ID + "=" + id, null);
    }
}

还有我的TableActivity.java（如果需要）

import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;

public class TableActivity extends AppCompatActivity {
    int currentTable;
    Button createNewBooking;
    List<Booking> bookings;
    TextView name;
    TextView time;
    DataAdapter adapter;
    RecyclerView recyclerView;
    DBHelper dbHelper;

    View.OnClickListener createNewBookingListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(TableActivity.this, BookingActivity.class);
            startActivity(intent);
        }
    };



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

        currentTable = MainActivity.getCurrentTable();
        createNewBooking = findViewById(R.id.createNewBooking);
        createNewBooking.setOnClickListener(createNewBookingListener);
        bookings = new ArrayList<>();

        dbHelper = new DBHelper(this);

        setInitialData();
        recyclerView = findViewById(R.id.list);
        recyclerView.setHasFixedSize(true);
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(linearLayoutManager);

        adapter = new DataAdapter(this, bookings);

        recyclerView.setAdapter(adapter);

    }

    private void setInitialData() {
        SQLiteDatabase database = dbHelper.getWritableDatabase();
        Cursor cursor = database.query(DBHelper.TABLE_BOOKINGS, null, null, null, null, null, null);

        if (cursor.moveToFirst()) {
            int nameIndex = cursor.getColumnIndex(DBHelper.KEY_NAME);
            int hoursIndex = cursor.getColumnIndex(DBHelper.KEY_HOURS);
            int minutesIndex = cursor.getColumnIndex(DBHelper.KEY_MINUTES);
            int phoneIndex = cursor.getColumnIndex(DBHelper.KEY_PHONE);
            do {
                bookings.add(new Booking(
                        currentTable,
                        cursor.getString(nameIndex),
                        cursor.getString(hoursIndex),
                        cursor.getString(minutesIndex),
                        cursor.getString(phoneIndex)
                        ));
            } while (cursor.moveToNext());
        } else {
            Toast.makeText(this, "Броней нет", Toast.LENGTH_SHORT).show();
        }
        cursor.close();
        dbHelper.close();
    }

}

有什么想法吗？

Answer 1

您要提供删除位置，无需ID与每个适配器位置相同。
试试这个：

crossImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                 Booking booking = bookings.get(getAdapterPosition());
                 datatype id = booking.getId();
                  removeAt(getAdapterPosition(),id);
            }
        });

public void removeAt(int position, dataType id) {
    bookings.remove(position);
    notifyItemRemoved(position);
    notifyItemRangeChanged(position, bookings.size());

    DBHelper.delete(id);
}

从RecyclerView + SQLite删除项目

1 个答案: