Question

1st Q: I have a database that I want to read from and I am pretty sure it is loading correctly since I don’t get an error message except when I tried to load it the very first time but every other time it loaded with out errors, why is that? Would this effect the app in any way on a device?

2nd Q: Is when I load the app and then click the back button to leave the app I get this error,

08-28 22:58:16.504: E/SQLiteDatabase(361): close() was never explicitly called on database '/data/data/com.example.databaseexample/databases/library_dev.db'

Am I not closing properly somewhere in my code? Thank you in advance for any help.

code:

public class MainActivity extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    DataBaseHelper myDbHelper = new DataBaseHelper(this);

    try{
        myDbHelper.createDataBase();
    }catch(IOException ioe){
        throw new Error("You f'd up, the database wasn't created *crys*");
    }

    try{
        myDbHelper.openDatabase();
    }catch(SQLException sqle){
        throw sqle;
    }
}

public void createListFromDB() {
    // TODO Auto-generated method stub


}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}
}

Here is my other class I use:

public class DataBaseHelper extends SQLiteOpenHelper{

private static String DB_PATH = "/data/data/com.example.databaseexample/databases/";    
private static String DB_NAME = "library_dev.db"; 
private SQLiteDatabase myDataBase;  
private final Context myContext;


public DataBaseHelper(Context c){
    super(c, DB_NAME, null, 1);
    this.myContext = c;
}

public void createDataBase() throws IOException{

    boolean dbExist =  checkDataBase();

    if(dbExist){
        //do nothing since the database already exist.
    }
    else{
        this.getReadableDatabase();

        try{
            copyDataBase();
        }catch(IOException e){
            throw new Error("Error Copying Database");
        }
    }       
}

private boolean checkDataBase(){

    SQLiteDatabase checkDB = null;

    try{
        String myPath = DB_PATH + DB_NAME;
        checkDB =  SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
    }catch(SQLiteException e){
        //database doesn't exist yet.
    }

    if(checkDB != null){
        checkDB.close();
    }

    return checkDB != null ? true : false;
}

private void copyDataBase()throws IOException{

    //Opens your local db as the input stream.
    InputStream myInput =  myContext.getAssets().open(DB_NAME);

    //Path to the just created empty DB.
    String outFileName =  DB_PATH + DB_NAME;

    //Opens the empty DB as the output stream.
    OutputStream myOutput = new FileOutputStream(outFileName);

    //transfer bytes from the inputfile to the outputfiles.
    byte[] buffer = new byte[1024];
    int length;
    while((length = myInput.read(buffer)) > 0){
        myOutput.write(buffer, 0, length);
    }

    //Close the Streams.
    myOutput.flush();
    myOutput.close();
    myInput.close();        
}

public void openDatabase() throws SQLException{

    //Open the database.
    String myPath = DB_PATH + DB_NAME;
    myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}

@Override
public synchronized void close(){
    if(myDataBase != null){
        myDataBase.close();
    }
}

@Override
public void onCreate(SQLiteDatabase db){

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion){

}

}

Answer 1

Question 1

You’re having this error because the first time you’re code is trying to open a database that doesn’t exist yet..in this case it creates a new one (copying it from input file).. so yes you’ll have this error on every phone since the first time you’ll launch the application there ‘ll be no database until you create it.. btw this is a very bad approach to handle you database.

Question 2

This happens because you’re not explicitly closing you’re database. you should do it on your onDestroy() method.. you should add this to your DataBaseHelper

public void closeDatabase() throws SQLException {
    // Close the database.
    myDataBase.close();
}

this method should be called within onDestroy() of your MainActivity.
I hope this helps you

UPDATE
you may check this tutorial it explains very well how to handle SQLite