SQLite - 无法检索所有值 - getString(int index) 不起作用

Question

在我的项目中，我有按如下方式命名的表：

places(int id auto increment, string placename, double latitude, double longitude, string placedetails)

现在，我创建了两个类，如下所示：

地点.java(用于模型(吸气者和二传手((

public class Place {
    private String mname;
    private double mlatitude,mlongitude;
    private String mplacedetails;
    public Place(String name, double latitude, double longitude,String placedetails)
        {
          mname = name;
          mlatitude = latitude;
          mlongitude = longitude;
          mplacedetails = placedetails;

    }
    public Place() {
    }

    public void setname(String placename)
    {
        mname = placename;

    }
    public String getname()
    {
        return mname;

    }
    public void setlatitude(double latitude)
    {
        mlatitude=latitude;

    }
    public double getlatitude()
    {
        return mlatitude;

    }

    public void setlongitude(double longitude)
    {
        mlongitude = longitude;

    }
    public double getlongitude()
    {
        return mlongitude;

    }

    public void  setPlacedetails(String placedetails)
    {
        mplacedetails = placedetails;
    }

    public String getplacedetails()
    {
        return mplacedetails;
    }

}

MySDQLiteHelper.java (扩展SQLiteOpenHelper的类(

public class MySqliteHelper extends SQLiteOpenHelper{
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_NAME = "MyApplicationDatabase";
    private static final String KEY_ID = "id";
    private static final String KEY_PLACENAME = "placename";
    private static final String KEY_PLACEDETAILS = "placedetails";
    private static final String KEY_LATITUDE = "latitude";
    private static final String KEY_LONGITUDE = "longitude";
    private static final String TABLE_NAME = "places";

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

    }
    @Override
    public void onCreate(SQLiteDatabase db) {

        //actual query = create table places (id primary key autoincrement, placename taxt, latitude real, longitude real);
        String query =  "CREATE TABLE " +TABLE_NAME + "( " + KEY_ID+
                " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_PLACENAME+
                " TEXT, "+ KEY_PLACEDETAILS+
                " TEXT, "+ KEY_LATITUDE+
                " REAL, "+KEY_LONGITUDE+ " REAL)";

                db.execSQL(query);
                Log.d("my", "Successfully created table: " + query);

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS places");
        this.onCreate(db);
    }

    public void addPlaces(Place place)
    {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues convalues = new ContentValues();

        convalues.put(KEY_PLACENAME,place.getname());
        convalues.put(KEY_LATITUDE,place.getlatitude());
        convalues.put(KEY_LONGITUDE,place.getlongitude());
        convalues.put(KEY_PLACEDETAILS,place.getplacedetails());
          db.insert(TABLE_NAME, null, convalues);
          Log.d("my","db.insert(TABLE_NAME, null, convalues)");
          Log.d("my", "Values inserted");
          db.close();
    }
    public Place getPlace(int id) {
        SQLiteDatabase  db = this.getReadableDatabase();
        Cursor cursor = db.query(TABLE_NAME, new String[] { KEY_ID, KEY_LATITUDE, KEY_LONGITUDE,
                        KEY_PLACENAME, KEY_PLACEDETAILS }, KEY_ID + "=?",
                new String[] { String.valueOf(id) }, null, null, null, null);
        if (cursor != null)
            cursor.moveToFirst();
       Place place = new Place(cursor.getString(1),
                cursor.getDouble(2), cursor.getDouble(3),cursor.getString(4));
        return place;
    }
    public List<Place> getAllPlaces() {
        List<Place> placeList = new ArrayList<Place>();

        SQLiteDatabase db = this.getWritableDatabase();
        String selectQuery = "SELECT  * FROM " + TABLE_NAME;
        Cursor cursor = db.rawQuery(selectQuery, null);
        Log.d("my","query fired");
        Log.d("my",cursor.toString());
        if (cursor.moveToFirst()) {
            Log.d("my","in movetofirst()");
            do {
                Log.d("my","in do");
                Place place = new Place();
                place.setname(cursor.getString(1));
                Log.d("my","place name");
                place.setlatitude(cursor.getDouble(2));
                place.setlongitude(cursor.getDouble(3));
                place.setPlacedetails(cursor.getString(4));
                placeList.add(place);
            } while (cursor.moveToNext());
        }

        return placeList;
    }

}

每次我从单击按钮时从活动中调用addPlace，例如：

        mpostplacename = (EditText) findViewById(R.id.edittext_placename);

        mpostplacedetails = (EditText) findViewById(R.id.edittext_placedetails);
        gps = new GPSTracker(RememberActivity.this);

        if(gps.canGetLocation()) {
            mylatitude = gps.getLatitude();
            mylongitude = gps.getLongitude();


            Toast.makeText(getApplicationContext(), "Your Location is - nLatitude: " + mylatitude + "nLongitude: " + mylongitude, Toast.LENGTH_LONG).show();

            myplacename = mpostplacename.getText().toString();
            myplacedetails = mpostplacedetails.getText().toString();
            if(myplacename==null)
            {
                  myplacename = mylatitude+"   "+mylongitude;
            }
            if(myplacedetails==null)
            {
                    myplacedetails = "No details given about this place";
            }
            MySqliteHelper db = new MySqliteHelper(this);

            db.addPlaces(new Place(myplacename, mylatitude, mylongitude, myplacedetails));

当我想在日志中显示存储的数据时，例如：

 MySqliteHelper db = new MySqliteHelper(this);
    List<Place> places = db.getAllPlaces();
    for (Place p : places) {
        String log = "name:" + p.getname() + " ,details: " + p.getplacedetails();
        Log.d("my", log);
    }

插入地名和地点详细信息

(作为一些字符串值，如blablabla等(后，日志显示地名正确，但地点详细信息错误：

D/my﹕ name:sdsdsda ,details: 0
D/my﹕ name:aaaaaaaaaaa ,details: 0

为什么getplacedetails不起作用？我在游标索引中找不到任何错误。可能是索引中的错误...因为它找不到索引上的位置详细信息。谁能帮我？

Answer 1

像这样替换代码行：

place.setname(cursor.getString(1));

像这样：

place.setname(cursor.getString(cursor.getColumnIndex(KEY_PLACENAME)));

看起来与KEY_PLACEDETAILS对应的列实际上是第 2 列，您正在尝试从第 4 列中获取一些内容。无论如何，使用 cursor.getColumnIndex() 使列与每个键匹配更安全，以防您的数据库稍后更改并帮助避免此类错误。

Answer 2

尝试这种方式来创建Place对象并在getAllPlaces(...)方法中添加placeList

   placeList.add(new Place(cursor.getString(1),cursor.getDouble(2),cursor.getDouble(3),cursor.getString(4)));

也改变你的地点.java

public class Place {
private String mname;
private double mlatitude,mlongitude;
private String mplacedetails;
public Place(String name, double latitude, double longitude,String placedetails)
    {
      this.mname = name;
      this.mlatitude = latitude;
      this.mlongitude = longitude;
      this.mplacedetails = placedetails;
 }
public void setname(String placename)
{
    this.mname = placename;
}
public String getname()
{
    return mname;
}
public void setlatitude(double latitude)
{
    this.mlatitude=latitude;
}
public double getlatitude()
{
    return mlatitude;
}
public void setlongitude(double longitude)
{
    this.mlongitude = longitude;
}
public double getlongitude()
{
    return mlongitude;
}
public void  setPlacedetails(String placedetails)
{
    this.mplacedetails = placedetails;
}
public String getplacedetails()
{
    return mplacedetails;
}
}