非常感谢！：） package com.example.fotooh2; import java.util.ArrayList; import java.util.List; import android.content.ContentV

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非常感谢！：）

  package com.example.fotooh2;



import java.util.ArrayList;

import java.util.List;



import android.content.ContentValues;

import android.content.Context;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteOpenHelper;



public class DatabaseHandler extends SQLiteOpenHelper {



    // All Static variables

    // Database Version

    private static final int DATABASE_VERSION = 4;



    // Database Name

    private static final String DATABASE_NAME = "PositionManager";



    //  Positions table name

    private static final String TABLE_POSITIONS = "positions";



    // Positions Table Columns names

    private static final String KEY_ID = "_id";

    private static final String KEY_NAME = "Name";

    private static final String KEY_KATEGORIE = "Kategorie";

    private static final String KEY_LAENGE = "Laenge";

    private static final String KEY_BREITE = "Breite";



    public DatabaseHandler(Context context) {

        super(context, DATABASE_NAME, null, DATABASE_VERSION);

    }



    // Creating Tables

    @Override

    public void onCreate(SQLiteDatabase db) {

        String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_POSITIONS + "("

                + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT," + KEY_KATEGORIE + " TEXT," + KEY_LAENGE + " TEXT,"+ KEY_BREITE + " TEXT" + ")";

        db.execSQL(CREATE_CONTACTS_TABLE);

    }



    // Upgrading database

    @Override

    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        // Drop older table if existed

        db.execSQL("DROP TABLE IF EXISTS " + TABLE_POSITIONS);



        // Create tables again

        onCreate(db);

    }



    /**

     * All CRUD(Create, Read, Update, Delete) Operations

     */



    // Adding new contact

    void addPosition(Position position) {

        SQLiteDatabase db = this.getWritableDatabase();



        ContentValues values = new ContentValues();

        values.put(KEY_NAME, position.getName()); //  Name

        values.put(KEY_KATEGORIE, position.getKategorie()); //  Kategorie

        values.put(KEY_LAENGE, position.getLaenge()); // Länge

        values.put(KEY_BREITE, position.getBreite()); // Breite



        // Inserting Row

        db.insert(TABLE_POSITIONS, null, values);

        db.close(); // Closing database connection

    }



    // Getting single position

    Position getPosition(int id) {

        SQLiteDatabase db = this.getReadableDatabase();



        Cursor cursor = db.query(TABLE_POSITIONS, new String[] { KEY_ID,

                KEY_NAME, KEY_KATEGORIE, KEY_LAENGE, KEY_BREITE  }, KEY_ID + "=?",

                new String[] { String.valueOf(id) }, null, null, null, null);

        if (cursor != null)

            cursor.moveToFirst();



        Position position = new Position
                (Integer.parseInt(cursor.getString(0)),
                cursor.getString(1), 
                cursor.getString(2), 
                cursor.getString(3), 
                cursor.getString(4));

        // return position

        return position;

    }



    // Getting All Positions

    public List<Position> getAllPositions() {

        List<Position> positionList = new ArrayList<Position>();

        // Select All Query

        String selectQuery = "SELECT  * FROM " + TABLE_POSITIONS;





        SQLiteDatabase db = this.getWritableDatabase();

        Cursor cursor = db.rawQuery(selectQuery, null);



        // looping through all rows and adding to list

        if (cursor.moveToFirst()) {

            do {

                Position position = new Position();

                position.setID(Integer.parseInt(cursor.getString(0)));

                position.setName(cursor.getString(1));

                position.setKategorie(cursor.getString(2));

                position.setLaenge(cursor.getString(3));

                position.setBreite(cursor.getString(4));



                // Adding position to list

                positionList.add(position);

            } while (cursor.moveToNext());

        }



        // return position list

        return positionList;

    }



    // Updating single position

    public int updatePosition(Position position) {

        SQLiteDatabase db = this.getWritableDatabase();



        ContentValues values = new ContentValues();

        values.put(KEY_NAME, position.getName());

        values.put(KEY_KATEGORIE, position.getKategorie());

        values.put(KEY_LAENGE, position.getLaenge());

        values.put(KEY_BREITE, position.getBreite());





        // updating row

        return db.update(TABLE_POSITIONS, values, KEY_ID + " = ?",

                new String[] { String.valueOf(position.getID()) });

    }



    // Deleting single position

    public void deletePosition(Position position) {

        SQLiteDatabase db = this.getWritableDatabase();

        db.delete(TABLE_POSITIONS, KEY_ID + " = ?",

                new String[] { String.valueOf(position.getID()) });

        db.close();

    }





    // Getting positions Count

    public int getPositionsCount() {

        String countQuery = "SELECT  * FROM " + TABLE_POSITIONS;

        SQLiteDatabase db = this.getReadableDatabase();

        Cursor cursor = db.rawQuery(countQuery, null);

        cursor.close(); 





        // return count

        return cursor.getCount();

    }



}