Question

This is basically my first android app and I have been trying to use a prefilled sqllite database to work out my requirements.

My problem is that onCreate function does not gets called.

I have taken bits of codes from many places and combined them to form this class.

Updating prepopulated database in Android

http://www.androidhive.info/2011/11/android-sqlite-database-tutorial/

And some others from android.com

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Locale;
import java.util.Random;

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

public class DatabaseHandler extends SQLiteOpenHelper {

    SQLiteDatabase db;
    private static final String TAG = "DataBaseHelper";
    int id = 0;
    Random random = new Random();
    private SQLiteDatabase myDataBase;
    private final Context myContext;

    // Constructor
    public DatabaseHandler(Context context) {
        super(context, DefinitionContract.DATABASE_NAME, null, DefinitionContract.DATABASE_VERSION);
        Log.d(TAG, "DatabaseHandler constructor called\n");
        db = getWritableDatabase();
        this.myContext = context;
        //createDB();
    }

    @Override
    public void onCreate(SQLiteDatabase db){
        Log.d(TAG, "onCreate called\n");
        createDB();
    }

    // Upgrading database
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.d(TAG, "onUpgrade called\n");
        Log.w(TAG, "Upgrading DB from version " + oldVersion + " to " +
                    newVersion + ", which will destroy all old data");

        // Drop older table if existed
        String sql  = "DROP TABLE IF EXISTS " + DefinitionContract.CATEGORY_TABLE_NAME;
        db.execSQL(sql);

        sql = "DROP TABLE IF EXISTS " + DefinitionContract.CONTENTS_TABLE_NAME;
        db.execSQL(sql);

        // Create table again
        onCreate(db);
    }

    public void createDataBase(SQLiteDatabase db) {
        Log.d(TAG, "createDataBase called\n");
        createDB();
        db.execSQL(DefinitionContract.CREATE_CATEGORY_TABLE);
        db.execSQL(DefinitionContract.CREATE_CONTENTS_TABLE);
    }

    private void createDB() {
        Log.d(TAG, "createDB called\n");
        boolean dbExist = dbExists();
        Log.d("SQL Helper", "Condition:\n");
        if(!dbExist) {
            Log.d("SQL Helper", "Condition 1\n");
            copyDataBase();
        } else if(dbExist) {
            Log.d("SQL Helper", "Condition 2\n");
            copyDataBase();
        }
    }

    private boolean dbExists() {
        Log.d(TAG, "dbExists called\n");
        //File dbFile = new File(DefinitionContract.DATABASE_PATH + DefinitionContract.DATABASE_NAME);
        //return dbFile.exists();

        SQLiteDatabase db = null;
        try {
            String dbPath = DefinitionContract.DATABASE_PATH + DefinitionContract.DATABASE_NAME;
            db = SQLiteDatabase.openDatabase(dbPath, null, SQLiteDatabase.OPEN_READWRITE);
            db.setLocale(Locale.getDefault());
            db.setLockingEnabled(true);
            db.setVersion(DefinitionContract.DATABASE_VERSION);
        }
        catch(SQLiteException e){
            Log.e("SQL Helper", "database not found");
        }
        if(db != null) {
            db.close();
        }
        return db != null ? true : false;
    }

    private void copyDataBase() {
        Log.d(TAG, "copyDataBase called \n");
        InputStream iStream = null;
        OutputStream oStream = null;
        String outFilePath = DefinitionContract.DATABASE_PATH + DefinitionContract.DATABASE_NAME;
        try{
            iStream = myContext.getAssets().open(DefinitionContract.DATABASE_NAME_EXT);
            oStream = new FileOutputStream(outFilePath);
            byte[] buffer = new byte[1024];
            int length;
            while((length = iStream.read(buffer))>0) {
                oStream.write(buffer,0,length);
            }
            oStream.flush();
            oStream.close();
            iStream.close();
        }
        catch(IOException ioe){
            throw new Error("Problem copying database from resource file.");
        }
    }

    public void openDataBase() throws SQLException {
        String myPath = DefinitionContract.DATABASE_PATH + DefinitionContract.DATABASE_NAME_EXT;
        myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
    }

    @Override
    public synchronized void close() {
        Log.d(TAG, "close called\n");
        if (myDataBase != null)
            myDataBase.close();
        super.close();
    }

    public void readDB() {
        Log.d(TAG, "readDB called\n");
        String selectQuery = "SELECT  * FROM " + DefinitionContract.DATABASE_ONLYNAME+"."+DefinitionContract.CATEGORY_TABLE_NAME;
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                int arraySize = cursor.getColumnCount();
                String newlog   = "arraySize=" + arraySize + "*****";
                for(int i = 0; i < arraySize; i++) {
                    newlog  = newlog + cursor.getString(i)+ "\n";
                }

                Log.d("Details: ", newlog);
            } while (cursor.moveToNext());
        }
    }

}

I have already done a google search and tried to fix it but it doesn’t work yet.

Android SQLiteOpenHelper : onCreate() method is not called. Why?

SQLiteOpenHelper failing to call onCreate?

LogCat showns only “DataBaseHandler constructor called” and then “shutting down VM” after that

But if I remove the db = getWritableDatabase(); line from my constructor it works further and shows that the readDB() function is being called.

Some definitions that might help in understanding my code:

public static final String DATABASE_NAME        = "mydb.db";

public static final String DATABASE_NAME_EXT        = "mydb.sqllite";

// Database path
public static final String DATABASE_PATH = "/data/data/com.abhishekgdotcom.collection/databases/";

Any help guys?

Answer 1

Well, the real reason why onCreate() method wasn’t working for me because it is called only the first time the app runs. Or when you change the DATABASE_VERSION then onUpgrade gets called which in turn calls the onCreate method again.

I believe this is the default android working.

P.S I could get the onCreate working everytime by either changing the database version or deleting the database file from /data/data/packagename/databases/