ios [__NSCFNumber length]: unrecognized selector sent to instance - ios

Question

i have created one custom cell and put button on it
and button event is like this
[cell.BtnRequest addTarget:self action:#selector(didTapButton:) forControlEvents:UIControlEventTouchUpInside];
and didtapbutton code is this
- (void)didTapButton:(id)sender {
WorkerDetailsVC *wvc=[self.storyboard instantiateViewControllerWithIdentifier:#"workerdetailsvc"];
NSIndexPath *indepath = [self.tblorderdata indexPathForCell:sender];
wvc.arrworkarrequest=[arrData objectAtIndex:indepath.row];
NSLog(#" arr send :%#", wvc.arrworkarrequest);
wvc.struserid = struserid;
[self.navigationController pushViewController:wvc animated:YES];
}
and on the next page i got the array arrworkarrequest and after the load all next page it will show error like this
2014-10-01 15:08:42.607 demo[2151:60b] -[__NSCFNumber length]: unrecognized selector sent to instance 0x911a860
2014-10-01 15:08:42.613 dmeo[2151:60b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFNumber length]: unrecognized selector sent to instance 0x911a860'

Answer 1

Your problem is that sender is of type UIButton not UITableViewCell so it's getting stuck in the [self.tblorderdata indexPathForCell:sender] because that method call expects a type of UITableViewCell.
You need to find the Cell that the button is in. You may be able to do this using a while loop (although it's a bit horrible). Something like:
id obj = sender;
while (![obj isKindOfClass:[UITableViewCell class]]) {
obj = [sender superview];
}
[self.tblorderdata indexPathForCell:obj];
This feels like it's abusing the view hierarchy though.

Answer 2

This happens if you compare the length of a string directly
for example
NSString *myString = #"2";
using this statement will generate the error
if(myString.length==2)