CODEWITHSUNDEEP
androidandroid-listview
Janusz
Janusz

Reputation: 189484

How to show dividers after some items in a listview?

I'm building a list that is sorted alphabetically. The list should show a divider containing the Letter that the following icons belong to.

I'm using a Cursoradapter that contains the already sorted result from the database. I plan on adding the divider to the list item and set it to visible if the shown letter changes. How do I know that I have a new Letter? Is there a better way then going forward or backward in the cursor and check if the item I show is the end or beginning of a new group?

Upvotes: 1

Views: 1447

Answers (1)

Gawcio
Gawcio

Reputation: 1175

You can do that in SQL query that provides data for Cursor.

Suppose we have person(name varchar) table.

Instead of asking just:

SELECT name FROM person ORDER BY name;

one can query:

SELECT p.name, CASE(
    SELECT COUNT(*) 
    FROM person 
    WHERE name<p.name and SUBSTR(name, 1, 1)=SUBSTR(p.name,1 , 1)
    ) WHEN 0 THEN 1 ELSE 0 END isFirst 
FROM person p 
ORDER BY name;

that gives (name, isFirst) resultset - each item starting with "new" letter will have isFirst set to 1 indicating start of new group.

edit: Example:

CREATE TABLE person(name varchar);
INSERT INTO person SELECT 'Jim' UNION SELECT 'Tom' UNION SELECT 'Ben' UNION SELECT 'John' UNION SELECT 'Alice' UNION SELECT 'Chris' UNION SELECT 'Anna' UNION SELECT 'Jerry';
SELECT p.name, CASE(
    SELECT COUNT(*) 
    FROM person 
    WHERE name<p.name and SUBSTR(name, 1, 1)=SUBSTR(p.name,1 , 1)
    ) WHEN 0 THEN 1 ELSE 0 END isFirst 
FROM person p 
ORDER BY name;

gives:

Alice|1
Anna|0
Ben|1
Chris|1
Jerry|1
Jim|0
John|0
Tom|1

Upvotes: 2

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