Retrieving data from different SQLite tables in Android?

Question

I was wondering if I have this situation:

In our SQLite databse, there are some tables (let's say four). each table consists of two columns: Title and Content.
We retrieved the titles from all the four tables, and display them in one ListView

The question is: How can we handle the onItemClickListener so that we can retrieve the Content of the selected item given that the items are from different tables?

I think I'll come across problem like that and I just want to know if it can be handled or not.

Thanks.

So if i understand the problem is that you have items from different tables and when you select on you have to identify from which table it is ? — Mojo Risin
– Mojo Risin, Commented Jul 10, 2011 at 7:50
Exactly both of you. In order to retrieve the corresponding Content — iTurki
– iTurki, Commented Jul 10, 2011 at 7:50

Nicklas A. · Accepted Answer · 2011-07-10 15:52:46Z

2

I'd say use an ArrayAdapter and wrap the data in a custom class that contains the table it came from (and ID etc if you need it), then you can get the ID and table by just knowing the index in the list.

The class could look something like this:

public static class ListItem {
    public String title, table;
    // Maybe include these as well?
    public String content;
    public int id;

    @Override
    public String toString() {
        return title; // Or something else maybe?
    }
}

Then simply build your data from the cursors into a ListItem[] and create the adapter like this:
new ArrayAdapter<ListItem>(data);

One problem with this solution is that you need to load everything in memory, if there is a lot of data you can create a custom Cursor which contains all four cursors and use a CursorAdapter instead.

edited Jul 10, 2011 at 15:52

answered Jul 10, 2011 at 7:51

Nicklas A.

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3 Comments

iTurki Over a year ago

I didn't get what you mean by build your data from the cursors into a ListItem[] . Can you explain?

Nicklas A. Over a year ago

You read a bunch of Cursors from your table using execSql, you iterate over all four (one for each table) adding each entry to the array.

iTurki Over a year ago

That seems nice. I hope I'll not stock with it :) . Thanks

Mojo Risin · Accepted Answer · 2011-07-10 07:59:26Z

1

The solution Nicklas A. proposed will do the trick. But if you have identical items why do you keep them in 4 different tables? If you items are identical it's betten to keep them in signle table and just to add some additional column to identify them if needed. If your items are not identical create 4 model classes for each of them and handle onItemClicked in each model.

answered Jul 10, 2011 at 7:59

Mojo Risin

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