android - 在android中添加到SQLite

Question

我正在尝试将多个项目添加到数据库中。但是，在读取操作期间，我总是得到最后一项。我添加了很多项目。但是，它们具有与最后添加的项目相同的内容。

例子:

06-03 18:30:19.343 16360-16360/com.example.wince.myapplication D/add: Yer [id=112, name=syndey, lat=-34.0, lng=151.0]
06-03 18:30:19.393 16360-16360/com.example.wince.myapplication D/add: Yer [id=112, name=syndey, lat=-34.0, lng=151.0]
06-03 18:30:19.433 16360-16360/com.example.wince.myapplication D/dalvikvm: GC_FOR_ALLOC freed 1776K, 49% free 10398K/20120K, paused 35ms, total 35ms
06-03 18:30:19.443 16360-16360/com.example.wince.myapplication D/add: Yer [id=112, name=syndey, lat=-34.0, lng=151.0]
06-03 18:30:19.483 16360-16360/com.example.wince.myapplication D/add: Yer [id=112, name=syndey, lat=-34.0, lng=151.0]
06-03 18:30:19.504 16360-16360/com.example.wince.myapplication D/add: Yer [id=112, name=istanbul, lat=-34.0, lng=151.0]
06-03 18:30:19.534 16360-16360/com.example.wince.myapplication D/add: Yer [id=112, name=vggg, lat=-34.0, lng=151.0]
06-03 18:30:19.554 16360-16360/com.example.wince.myapplication D/add: Yer [id=112, name=ankara, lat=-34.0, lng=151.0]
06-03 18:30:19.584 16360-16360/com.example.wince.myapplication D/add: Yer [id=112, name=bagdat, lat=-34.0, lng=151.0]

我读到的是:

D/getAllBooks(): [Yer [id=120, name=bagdat, lat=-34.0, lng=151.0], 
    Yer [id=120, name=bagdat, lat=-34.0, lng=151.0], 
    Yer [id=120, name=bagdat, lat=-34.0, lng=151.0], 
    Yer [id=120, name=bagdat, lat=-34.0, lng=151.0], 
    Yer [id=120, name=bagdat, lat=-34.0, lng=151.0], 
    Yer [id=120, name=bagdat, lat=-34.0, lng=151.0], 
    Yer [id=120, name=bagdat, lat=-34.0, lng=151.0], 
    Yer [id=120, name=bagdat, lat=-34.0, lng=151.0],
....

这是我将它们添加到数据库的方式

public void onClick(DialogInterface dialog2, int which) {
    m_Text = input.getText().toString();
    LatLng sydney = new LatLng(-34, 151);
    VT.add(new Yer("syndey", sydney.latitude, sydney.longitude));
    VT.add(new Yer("syndey", sydney.latitude, sydney.longitude));
    VT.add(new Yer("syndey", sydney.latitude, sydney.longitude));
    VT.add(new Yer("syndey", sydney.latitude, sydney.longitude));
    VT.add(new Yer("istanbul", sydney.latitude, sydney.longitude));
    VT.add(new Yer(m_Text, sydney.latitude, sydney.longitude));
    VT.add(new Yer("ankara", sydney.latitude, sydney.longitude));
    VT.add(new Yer("bagdat", sydney.latitude, sydney.longitude));
}

我只是使用 getall 函数来获取它们。

这是我的助手类。

package com.example.wince.myapplication;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

import java.util.LinkedList;
import java.util.List;

/**
 * Created by Wince on 2.06.2016.
 */
public class VeriTabani extends SQLiteOpenHelper {
    //  table name
    private static final String TABLE = "Kayitlar";

    //  Table Columns names
    private static final String KEY_ID = "id";
    private static final String KEY_NAME = "isim";
    private static final String KEY_LAT = "latitude";
    private static final String KEY_LNG = "longitude";

    private static final String[] COLUMNS = {KEY_ID,KEY_NAME,KEY_LAT,KEY_LNG};
    // Database Version
    private static final int DATABASE_VERSION = 1;
    // Database Name
    private static final String DATABASE_NAME = "KayitDB";

    public VeriTabani(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // SQL statement to create  table
        String CREATE_TABLE = "CREATE TABLE Kayitlar ( " +
                "id INTEGER PRIMARY KEY AUTOINCREMENT, " +
                "isim TEXT, " +
                "latitude REAL,"+
                "longitude REAL )";

        // create kayıtlar table
        db.execSQL(CREATE_TABLE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // Drop older books table if existed
        db.execSQL("DROP TABLE IF EXISTS ");

        // create fresh books table
        this.onCreate(db);
    }
    public void add(Yer veri){
        //for logging
        Log.d("add", veri.toString());

        // 1. get reference to writable DB
        SQLiteDatabase db = this.getWritableDatabase();

        // 2. create ContentValues to add key "column"/value
        ContentValues values = new ContentValues();
        values.put(KEY_NAME, Yer.getName()); // get title
        values.put(KEY_LAT,Yer.getLat() ); // get author
        values.put(KEY_LNG,Yer.getLng());

        // 3. insert
        db.insert(TABLE, // table
                null, //nullColumnHack
                values); // key/value -> keys = column names/ values = column values

        // 4. close
        db.close();
    }
    public Yer getYer(int id){

        // 1. get reference to readable DB
        SQLiteDatabase db = this.getReadableDatabase();

        // 2. build query
        Cursor cursor =
                db.query(TABLE, // a. table
                        COLUMNS, // b. column names
                        " id = ?", // c. selections
                        new String[] { String.valueOf(id) }, // d. selections args
                        null, // e. group by
                        null, // f. having
                        null, // g. order by
                        null); // h. limit

        // 3. if we got results get the first one
        if (cursor != null)
            cursor.moveToFirst();

        // 4. build  object
        Yer yer = new Yer();
        yer.setId(Integer.parseInt(cursor.getString(0)));
        yer.setName(cursor.getString(1));
        yer.setLat(cursor.getDouble(2));
        yer.setLng(cursor.getDouble(3));

        Log.d("getBook("+id+")", yer.toString());

        // 5. return
        return yer;
    }

    // Get All
    public List<Yer> getAllYer() {
        List<Yer> yerler = new LinkedList<Yer>();

        // 1. build the query
        String query = "SELECT  * FROM " + TABLE;

        // 2. get reference to writable DB
        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(query, null);

        // 3. go over each row, build book and add it to list
        Yer yer = null;
        if (cursor.moveToFirst()) {
            do {
                yer = new Yer();
                yer.setId(Integer.parseInt(cursor.getString(0)));
                yer.setName(cursor.getString(1));
                yer.setLat(cursor.getDouble(2));
                yer.setLng(cursor.getDouble(3));

                // Add book to books
                yerler.add(yer);
            } while (cursor.moveToNext());
        }

        Log.d("getAllBooks()", yerler.toString());

        // return books
        return yerler;
    }

    // Updating single
    public int updateBook(Yer yer) {

        // 1. get reference to writable DB
        SQLiteDatabase db = this.getWritableDatabase();

        // 2. create ContentValues to add key "column"/value
        ContentValues values = new ContentValues();
        values.put("Name", yer.getName()); // get title
        values.put("Lat", yer.getLat()); // get author
        values.put("Lng",yer.getLng());

        // 3. updating row
        int i = db.update(TABLE, //table
                values, // column/value
                KEY_ID+" = ?", // selections
                new String[] { String.valueOf(yer.getId()) }); //selection args

        // 4. close
        db.close();

        return i;

    }

    // Deleting single
    public void deleteBook(Yer yer) {

        // 1. get reference to writable DB
        SQLiteDatabase db = this.getWritableDatabase();

        // 2. delete
        db.delete(TABLE,
                KEY_ID+" = ?",
                new String[] { String.valueOf(yer.getId()) });

        // 3. close
        db.close();

        Log.d("deleteBook", yer.toString());

    }
}

Answer 1

我认为问题出在你的 Yen 类上

static private int id; 
static private Double Lng; 
static private Double Lat; 
static private String Name

我认为问题出在 Yen 变量成员上……它们是静态的。因此，所有对象都共享相同的内存位置(因此，只显示最后保存的值)

去掉那些Yen类成员的static修饰符