iphone - UITableView anchor rows to bottom

Question

I have a UITableView that needs to introduce new content from the bottom. This is how a table view behaves when the view is full and you add new rows with animation.

I was starting it by altering the contentInset as rows are introduced but then when they change things go off, and the entry animation is all wrong... My problem with this approach is compounded by the fact that users can delete rows, and the row contents update, causing them to resize (each row has it's own height which changes).

Any recommendations on how to get a UITableView rows to always appear at the bottom of the UITableView's view space?

Answer 1

I've got a solution that works for me perfectly, but it causes a bunch of double thinking so it's not as simple in theory as it is in practice... kinda...

Step 1, apply a transform to the table view rotating it 180deg

tableView.transform = CGAffineTransformMakeRotation(-M_PI);

Step 2, rotate your raw cell 180deg in tableView:cellForRowAtIndexPath:

cell.transform = CGAffineTransformMakeRotation(M_PI);

Step 3, reverse your datasource. If you're using an NSMutableArray insert new objects at location 0 instead of using AddObject...

Now, the hard part is remembering that left is right and right is left only at the table level, so if you use

[tableView insertRowsAtIndexPaths:targetPath withRowAnimation:UITableViewRowAnimationLeft]

it now has to be

[tableView insertRowsAtIndexPaths:targetPath withRowAnimation:UITableViewRowAnimationRight]

and same for deletes, etc.

Depending on what your data store is you may have to handle that in reverse order as well...

Note: rotate the cells OPPOSITE the table, otherwise floating point innacuracy might cause the transform to get off perfect and you'll get crawlies on some graphics from time to time as you scroll... minor but annoying.