How to deal with screen position constants in iPhone code? - iphone

Question

I have a requirement to fill cells with varying length wraparound text. My current routine is handling this satisfactorily, however, I am concerned about the use of a couple of constants being used.
The values 10 and 260 below represent the margin and cell width expected, but they are only accurate for standard definition resolution in portrait orientation.
Is there some screen/table object that provides me these values as metrics I could use instead of the constants?
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell;
UILabel *lbl;
CGRect frame;
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero
reuseIdentifier:AnswerIdentifier] autorelease];
frame.origin.x = 10;
frame.origin.y = 10;
frame.size.height = [self textHeight:indexPath];
frame.size.width = 260;
lbl = [[UILabel alloc] initWithFrame:frame];
lbl.lineBreakMode = UILineBreakModeWordWrap;
lbl.numberOfLines = 0;
[cell.contentView addSubview:lbl];
[lbl release];
return cell;
}
- (CGFloat)textHeight:(NSIndexPath *)indexPath {
CGSize textSize;
CGSize constraintSize;
CGFloat height;
NSString *theText = [self cellText:indexPath];
constraintSize = CGSizeMake(260.0f, MAXFLOAT);
textSize = [theText sizeWithFont:kCELL_FONT
constrainedToSize:constraintSize
lineBreakMode:UILineBreakModeWordWrap];
height = textSize.height;
return height;
}

Answer 1

The table obviously needs to fit in the frame of the containing view (which might be the top level view or the window), so I might use percentage or pixel offsets from that rect.

Answer 2

Try using
[[UIScreen mainScreen] applicationBounds];
This will return a CGRect for the current window size. Then, for your code, you might use:
CGRect screenRect = [[UIScreen mainScreen] applicationBounds];
frame.origin.x = 10;
frame.origin.y = 10;
frame.size.height = [self textHeight:indexPath];
frame.size.width = screenRect.size.width - 60.0;
Assuming that the pixel offsets in x are fixed, with flexible label width.