XCode iOS7 - Dynamic cell with UITextView like Reminder App - ios

Question

I need to create an application that have the same behavior as built-in Reminder App. There are some problems to create this:
Cells that have dynamic height and "grow" as the content of the UITextView
Select the touched cell
Refresh the height of the cell when the user has edited the content(on the fly)
I've already solved the dynamic height, using some trick.
The problem that remains is:
How to know which cell the user has selected if the cell is "fully" with the UITextView ?
Right Now i've used the method textViewDidBeginEditing to know the cell and scroll the UITableView to it:
- (void)textViewDidBeginEditing:(UITextView*)textView
{
MemoViewCell* cell = (MemoViewCell *)[self parentCellFor:textView];
if (cell)
{
NSIndexPath* indexPath = [self.tableView indexPathForCell:cell];
currentIndexPath = indexPath;
[self.tableView scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionMiddle animated:YES];
}
}
- (UITableViewCell*)parentCellFor:(UIView*)view
{
if (!view)
return nil;
if ([view isMemberOfClass:[MemoViewCell class]])
return (UITableViewCell*)view;
return [self parentCellFor:view.superview];
}
How to refresh the cell height without lost the focus?
To this, i've used this method:
-(void)textViewDidChange:(UITextView *)textView
{
NSMutableDictionary *dataSourceItem = [self.model.dataSource objectAtIndex:currentIndexPath.row];
[dataSourceItem setObject:textView.text forKeyedSubscript:#"body"];
[self.model.dataSource setObject:dataSourceItem atIndexedSubscript:currentIndexPath.row];
[self.tableView beginUpdates];
[self.tableView endUpdates];
}
When the text change, i get the new text, i change it in the Model and i call beginUpdated and endUpdates.
Sure, this works, but all is extremly slow... do you have some idea to to this in a more elegant way and maybe... efficient?
If i call reloadRowsAtIndexPaths: i lost the focus on the cell.

Answer 1

First of all, if you use the delegate method - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath; in your dynamic height trick, remember to implement this method along - (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath;, it helps a lot in terms of performance.
Then to focus on your specific project, if I correctly understood your goal, what you really want is to update the layout of your table view only when your text view is modified. Currently you're updating it at each text change. You might consider using a condition inside -(void)textViewDidChange:(UITextView *)textView, such as :
if ([textView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height !=
textView.frame.size.height) {
[self.tableView beginUpdates];
[self.tableView endUpdates];
}
The condition given as example will work only if your existing cell layout respects the intrinsic content size of the text view, otherwise you will need to adapt the condition.