Question

可能重复：
force close at cursor line!

我必须创建一个从Sqlite数据库中读取一些GPS数据的应用程序，但每次我尝试从数据库中查询时我都会强行关闭。所以我尝试了一些简单的事情：在数据库中插入几行并要求他们在程序中......但是有了这样简单的东西，我仍然会强行关闭。事情就是当我尝试在我的项目之外运行这个类时，它运行正常。这是我创建数据库的帮助类：

package test.android;

import java.util.ArrayList;
import java.util.List;

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

public class CoordonateDbAdapter {


    public static final String KEY_ROWID = "_id";
    public static final String KEY_LONGITUDE= "longitude";
    public static final String KEY_LATITUDE = "latitude";
    public static final String KEY_COUNTRY= "country";
    public static final String KEY_TOWN= "town";
    public static final String KEY_STREET = "street";

    private static final String TAG = "CoordonateDbAdapter";
    private DatabaseHelper mDbHelper;
    private SQLiteDatabase mDb;




    private static final String DATABASE_CREATE =
            "create table masini (_id integer primary key autoincrement, "
                    + "longitude text not null, latitude text not null," +
                   "country text not null,town text not null,street text not null);";

    private static final String DATABASE_NAME = "gps";
    private static final String DATABASE_TABLE = "masini";
    private static final int DATABASE_VERSION = 1;

    private final Context mCtx;

    private static class DatabaseHelper extends SQLiteOpenHelper {

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

        @Override
        public void onCreate(SQLiteDatabase db) {

            db.execSQL(DATABASE_CREATE);
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                    + newVersion + ", which will destroy all old data");
            db.execSQL("DROP TABLE IF EXISTS notes");
            onCreate(db);
        }
    }
    public CoordonateDbAdapter(Context ctx) {
        this.mCtx = ctx;
    }
    public CoordonateDbAdapter open() throws SQLException {
        mDbHelper = new DatabaseHelper(mCtx);
        mDb = mDbHelper.getReadableDatabase();
        return this;
    }

    public void close() {
        mDbHelper.close();
    }



    public long insertData(String longitude, String latitude, String country, String town, String street) {
         ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_LONGITUDE, longitude);
        initialValues.put(KEY_LATITUDE, latitude);
        initialValues.put(KEY_COUNTRY, country);
        initialValues.put(KEY_TOWN, town);
        initialValues.put(KEY_STREET, street); 
        return mDb.insert(DATABASE_TABLE, null, initialValues);
    }




    public boolean deleteData(long rowId) {

        return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
    }
   public Cursor fetchAllData() throws SQLException{



     return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_LONGITUDE,KEY_LATITUDE,KEY_COUNTRY,KEY_TOWN,KEY_STREET}, null, null, null, null, null);



   }

    public Cursor fetchData(long rowId) throws SQLException {

        Cursor mCursor = mDb.query(true, DATABASE_TABLE, new String[] 
                    {KEY_ROWID, KEY_LONGITUDE,KEY_LATITUDE,KEY_COUNTRY,KEY_TOWN,KEY_STREET}, 
                     KEY_ROWID + "=" + rowId, null, null, null, null, null);
        if (mCursor != null) {
            mCursor.moveToFirst();
        }
        return mCursor;
    }
    public boolean updateNote(long rowId, String longitude, String latitude,String country, String town,String street) {
        ContentValues args = new ContentValues();
        args.put(KEY_LONGITUDE, longitude);
        args.put(KEY_LATITUDE, latitude);
        args.put(KEY_COUNTRY, country);
        args.put(KEY_TOWN, town);
        args.put(KEY_STREET, street);

        return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
    }


}

And the class that uses it is:
package test.android;

import java.util.List;

import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.widget.Toast;
public class screen_database extends Activity{

      public void onCreate(Bundle savedInstanceState) {
                super.onCreate(savedInstanceState);
            setContentView(R.layout.screen_database);
           CoordonateDbAdapter db = new CoordonateDbAdapter(this); 
          db.open();
          long id;
       id= db.insertData("-36.2", "125","Romania","Cluj","Zorilor");
       db.insertData("44", "55","Romania","Iasi","Alexandru Ioan Cuza");
             Cursor c=db.fetchAllData();
}
}

我尝试将它重复...然后我逐行继续我的程序，异常就在这一行

 Cursor c=db.fetchAllData();

当我进入调试器时，它会在此行被阻止：

 return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_LONGITUDE,KEY_LATITUDE,KEY_COUNTRY,KEY_TOWN,KEY_STREET}, null, null, null, null, null);

我真的不知道是什么原因造成这种情况，因为在我的应用程序之外它运行正常。我有很多类，这个是在我经历其他几个意图后调用的。当我逐行进行调试时，这些函数被称为应该如何调用它们，从少数人的角度来看是好的...我不知道那条线路有什么问题。如果你有任何想法我真的会想到它因为我已经不在了....谢谢！

请求光标时出错

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