Develop Reference

Managing a sqlite database using activity list

Ok, I have a database with id column as timestamp
I made an activity list from the db.
I want to manage the db (delete rows) using the list, but the thing is I don't want to
View the whole timestamp, in every row I'll put only the time with some info and
I want to group the list ,as in contacts grouped by alphabet, by the date.
First, how can I make group in an activity list? (Making groups to the output list not the db)
Second, what is the best way to implement this? When user chooses an item and confims delete
I should delete it from the db but I have only patial timestamp...
(My only link to the db is the timestamp - I don't actually know where to store it in the list and I don't want to put it as a string in the text view, do a substring to get it back - is there another way to do this?)
I tried to search tthe web for some examples but I only found a simple ones.
Thnx :-)

?
I think what you're trying to do is create a database of tasks identified by a timestamp. You probably don't want to use a timestamp as a unique ID for the row. Instead, use an integer and qualify it as "PRIMARY KEY" when you create the database.
group the list? I'm not sure why you want to do this in the structure of the database. It's more common to group the list in the output, and leave the db itself in as flat a structure as possible.
Retrieve the primary key when you display a list of tasks. When the user clicks a task, use the primary key to choose the task to delete. You don't have to display the primary key; it serves as a behind-the-scenes "link" between the displayed info and the db row.

http://www.vogella.com/articles/AndroidListView/article.html
I should use cursor adapter for managing db.
And this one for grouping a list:
http://code.google.com/p/android-amazing-listview/
Thnx for the efforts

Android AutoCompleteTextView suggestion if nothing is found

I am making a point of sale app for Android, and I have a AutoCompleteTextView loaded in with the database of items that they can buy, but I also want the AutoCompleteTextView to double as a way to add custom items/notes into the order.
So for example, the customer is ordering Steak, but doesnt want any seasoning. My database includes options for 'No Onions' 'No Mushrooms', etc, but not 'No Seasoning', and if the waiter types in 'No Seasoning' into the AutoCompleteTextView, I want a suggestion 'Add as Note' to pop up.
Is there a way to add this suggestion when no other suggestions are found, either by making it always on the dropdown list (making it not able to be filtered out), or by detecting when no items are on the dropdown list and adding it in then?

I think this can be done using MatrixCursor.
When you retrieve the cursor from your database, check if its empty with Cursor.moveToFirst(). Then either fill the MatrixCursor with your database cursor or a single "Add as Note" item if empty.
I use this to combine two database Cursor in one for suggestions here (method getUrlSuggestions(), the last one). Note that this example is not very clean, as all values are casted to String before insertion in the MatrixCursor. This is not necessary as the addRow() method take an array of Object.

ListView row id and position index confusion

I'm just starting to dive into some basic Android development and have been experimenting with a ListView and integrating it with a SimpleCursorAdapter. I look through a lot of online code samples, but I also have a book to use as a reference (Professional Android 2 Application Development).
In the book they work out an example To-Do list application that stores the list items in a SQLite database with an auto-incrementing, integer, primary key field.
A user can create new list items, but can also delete a selected item from the list. In the code, when the delete occurs, the primary key field is restricted (within the WHERE clause of the SQL statement) by the position attribute of the item as opposed to the item's rowid.
To me, this seems like an incorrect implementation. Looking at the SQLite documentation for AUTOINCREMENT, it says that this value will always increase and old values will never be re-used on the same table. So if you're deleting and adding things to the list, it would seem that the position and row id can get out of sync rather quickly.
Am I correct, then, to assume that the row id is the correct way to "index" into the database table and not the list position? I think the position would be safe to use if one is using the regular ListAdapter, but doesn't seem suitable when indexing into the database.

You can use the position to get a cursor to a particular list entry (and this cursor would be the 'row' in the 'table' corresponding to the row id):
Cursor cursor = (Cursor)parent.getItemAtPosition(pos);
int rowCol = c.getColumnIndex("_id");
Then you should see that cursor.getLong(rowCol) == id

That is definitely bad practice. I always use the row id to delete, and use the position id to retrieve the cursor's row id. I have the first edition of that book at home, I'm going to take a look at it myself later.

Order of insert in android database

I am wondering how can I insert an element at the beginning of the data base? I want to do this because:
a) I want to display the elements (ListView) as 'last-inserted on top and first-inserted on the bottom' (like a stack)
b) I want to limit the amount of elements in my db. When a new element is added (over the limit) I can put the new one (at the beginning) and delete the last one. (Don't know yet how to delete the last element).
I was searching for a solution but I am starting to wonder I have any control of how the element are inserted. If not I was thinking about displaying the database from end to bottom. But don't actually know how to do it since the cursor is always set at the beginning of the db. If could achieve this I can solve b) by deleting the first element (again don't know how to achieve this yet).

Every row of every SQLite table has a 64-bit signed integer key that uniquely identifies the row within its table. This integer is usually called the "rowid"
To get last inserted at top and first inserted at bottom....
SELECT * from mytable order by ROWID desc;
Read more about ROWID here
And, to delete the oldest:
DELETE from mytable WHERE ROWID = (SELECT MIN(ROWID) FROM mytable);
If you use the ROWID, you do not have to modify your existing table. And, the value of ROWID is guaranteed.

You can store a timestamp (as a new field) when you insert a record into your database. Then you delete the oldest record you can find if it is over the limit (e.g. using MAX SQL keyword). You can display the records in reverse-chronological order by sorting DESC with your timestamp field.

Expandable ListView and cursor adapter

I have a ListView which uses cursor adapter to show the records from database. When a new records is inserted in database ,it works great and shows that entry on top of ListView on requery.
Now I am facing problem when User scroll down the List, background thread call web service and brings old data. In this case when it does requery, old data is also getting appended on top of list which should append old data at the end of list.
What should i need to do differently, to add old data at the end of List rather than top ? do i need to change method of insertion when I am getting this old data ?

I think you need to store a date field in your bd table and make an ORDER BY in the query....