我的SQLite数据库中的上下文有问题，但我找不到它。 （使用SQLiteAssetHelper）

Question

I have some troubles with my Database activity.

I have my database (Voedsel.rar), in assets-databases-Voedsel.rar.

I also have one SQLView activity, which should be able to view the database. Also, I have the SQLite activity (for writing new products to it.), and my regular Database activty. I want to write to the database, and to view the database.

There are 3 columns, Product, Eenheid (translated it means 'unit'), and Kcal (the amount of kilocalories in that specific units of that specific food-product.). Hopefully you all understand me. :)

I'll add my activities. If there is need of the layout files, don't hesitate to ask.

So, the first question is:

How can I fix my error in line 46, (see comment!)...?

Is there someting wrong with the Context?

my Database activity:

    package com.jacob.eindproject;

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.database.sqlite.SQLiteDatabase.CursorFactory;

import java.sql.*;

import com.readystatesoftware.sqliteasset.SQLiteAssetHelper;

public class Database extends SQLiteAssetHelper {

    public static final String KEY_PRODUCT = "Product";
    public static final String KEY_EENHEID = "Eenheid";
    public static final String KEY_KCAL = "Kcal";

    private static final String DATABASE_NAME = "Voedsel";
    private static final String DATABASE_TABLE = "Voeding";
    private static final int DATABASE_VERSION = 1;

    private DbHelper ourHelper;
    private final Context ourContext;
    private SQLiteDatabase ourDatabase;

    private static class DbHelper extends SQLiteAssetHelper{

        public DbHelper(Context context) {
            super(context, DATABASE_NAME, context.getExternalFilesDir(null).getAbsolutePath(), null, DATABASE_VERSION);
            // TODO Auto-generated constructor stub
        }

    }

        @Override
        public void onUpgrade(SQLiteDatabase Voedsel, int oldVersion, int newVersion) {
            Voedsel.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);
            onCreate(Voedsel);
        }



    public Database(Context ourContext){ 

//Here is my error. It says: 
//Implicit super constructor 
//SQLiteAssetHelper() is undefined. Must explicitly invoke another constructor

        Context = ourContext;
    }

    public Database open() throws SQLException{
        ourHelper = new DbHelper(ourContext);
        ourDatabase = ourHelper.getWritableDatabase();
        return this;        
    }

    public void close() {

    ourHelper.close();
}



    public long createEntry(String product, String kcal, String eenheid) {
        ContentValues cv = new ContentValues();
        cv.put(KEY_PRODUCT, product);
        cv.put(KEY_EENHEID, eenheid);
        cv.put(KEY_KCAL, kcal);
        return ourDatabase.insert(DATABASE_TABLE, null, cv);

    }

    public String getData() {
        // TODO Auto-generated method stub
        String[] columns = new String[]{ KEY_PRODUCT, KEY_EENHEID, KEY_KCAL};
        Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
        String result = "";

        int iProduct = c.getColumnIndex(KEY_PRODUCT);
        int iEenheid = c.getColumnIndex(KEY_EENHEID);
        int iKcal = c.getColumnIndex(KEY_KCAL);

        for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
            result = result + c.getString(iProduct) + " " + c.getString(iEenheid) + " " + c.getString(iKcal) + "\n";


        }

        return result;
    }

    public void close(Database database) {
        // TODO Auto-generated method stub

    }



}

Answer 1

You need to call the super constructor. An example from this site is the following:

super(context, DATABASE_NAME, null, DATABASE_VERSION);

It looks like the addition of this line as the first line in your constructor should remove the error.

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

Secondly, you seem to have an inner SQLiteHelp. I can't imagine why that's needed, so I would just remove it.

private static class DbHelper extends SQLiteAssetHelper{

    public DbHelper(Context context) {
        super(context, DATABASE_NAME, context.getExternalFilesDir(null).getAbsolutePath(), null, DATABASE_VERSION);
        // TODO Auto-generated constructor stub
    }

}

Lastly, I would call your class something different than Database. I think you might be confusing classes somewhere, which could be responsible for your issue.