Question

I have this code:

DatabaseHandler db = new DatabaseHandler(this);
System.out.println("Start - " + System.currentTimeMillis());
for (int i = 1; i < db.getChampsCount() + 1; i++) {
    String name = db.getChampInfo(i, "name");
    String title = db.getChampInfo(i, "title");
    String thumb = db.getChampInfo(i, "thumb");
    System.out.println("End - " + System.currentTimeMillis());
    [...]
}

and this

String getChampInfo(int id, String col) {
    SQLiteDatabase db = this.getReadableDatabase();

    Cursor cursor = db.rawQuery("SELECT " + col + " FROM champions WHERE id = " + id, new String[] {});
    if (cursor != null)
        cursor.moveToFirst();

    db.close();
    return cursor.getString(0);
}

Which is a part of DatabaseHelper class

And it works ok, but the problem is it takes way too long to execute (2089ms on my android phone). Those strings are a part of the UI so I don’t think I can put that in another thread. What can i do to make this code run faster?

Edit: there are exactly 110 rows

Answer 1

Instead of individual statement, should you not use Single sql statement ?

Just create one ArrayList which will store all the required value in the Activity class.

e.g: ArrayList<String> myData;

Now in database helper class make one function like below:

 // TO get All Data of datanase which you want
public ArrayList<String> getAllData() {          
    ArrayList<String> subTitleList = null;         
    Cursor cursor = null;          
    try {              
    String queryString = "SELECT * FROM champions";              
        cursor =  db.rawQuery(queryString, null);              
        if (cursor != null && cursor.moveToFirst()) {                 
            subTitleList = new ArrayList<String>();                 
            do {                     
                String nextUser = new String(cursor.getString(cursor.getColumnIndex("name")));                     
                String nextUser = new String(cursor.getString(cursor.getColumnIndex("title")));                     
                String nextUser = new String(cursor.getString(cursor.getColumnIndex("thumb")));                     

                subTitleList.add(nextUser);                 
            } 
            while (cursor.moveToNext());   
            System.out.println("it comes in SubTitleList");
        }         
    } 
    catch (Exception e) {             
        e.printStackTrace();             
        subTitleList = null;         
    } 
    finally {             
        if (cursor != null && !cursor.isClosed()) {                 
            cursor.deactivate();                 
            cursor.close();                 
            cursor = null;             
        }             
        if(db != null){                 
            db.close();             
        }         
    }
    //System.out.println("SubTitleList is: "+subTitleList);
    return subTitleList;   
}

And now in your activity class you can call this function and get all the required data from the myData ArrayList.

myData = db.getAllData(); // i think there is no need of any ID if you are fetching all the data.

Hope you got my point.