How to pass values to AsyncTask Android

Question

This is the first time i am using AsyncTask and probably a little confused as well, about passing the values.

I have 4 ArrayList<String> s, which contain data that should be inserted into the database. I want this insertion to be done in background. There will be a minimum of 50 rows to be inserted into the database and 1 row is inserted at a time, by taking passing values from 4 arraylists that i have.

Can someone guide me on how to do this?

Now i create a subclass InsertData that extends AsyncTask :::

private class InsertData extends AsyncTask<Params, Progress, Result>{

        @Override
        protected Result doInBackground(Params... params) {
            // TODO Auto-generated method stub
            return null;
        }   
}

I have values in 4 arraylists, in which i need to retrieve 1 entry from each arraylist and pass the 4 values to the database. How do i pass these 4 values to the AsyncTask and also, how do i repeat this till there are entries in the arraylists.

Here is the database method that inserts 1 row into the database :::

public void insert_row(int count, String image_url, String name, String number) {
        // TODO Auto-generated method stub

        db.execSQL("INSERT INTO contacts VALUES('"+ count +"', '"+ image_url +"', '"+ name +"', '"+ number +"')");
    }

If someone can give me a overview on how i can implement this, It would be great.

Answer 1

Try the following, and, anyway, you could create constructor for InsertData with parameters you need, store them in InsertData class fields and use in doInBackground().

private class InsertData extends AsyncTask<ArrayList, Progress, Result>{

            @Override
            protected Result doInBackground(ArrayList... params) {
                // TODO Auto-generated method stub
                ArrayList list1 = params[0];
                ArrayList list2 = params[1];
                ...
                return null;
            }   
    }

Call:

InsertData task = new InsertData();
task.execute(yourList1, yourList2, yourList3...);

Answer 2

You can directly pass the lists to the doInBackground() like this and do all your 50 iterations there.

private class InsertData extends AsyncTask<List<String>, Progress, Result>{

    @Override
    protected Result doInBackground(List<String>... params) {
        // TODO Auto-generated method stub
        List<String> list1 = params[0];
        List<String> list2 = params[1];
        List<String> list3 = params[2];
        List<String> list4 = params[3];

        // Do the 50 iterations here.        

        return null;
    }   
}

And you can pass the lists to this AsyncTask like this:-

new InsertData().execute(list1, list2, list3, list4);