I have found solution for this problem
it was caused by reloading data.
for this purpose i try to reload data only when keyboard hide.
in viewDidLoad
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardDidShow:)
name:UIKeyboardWillShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:nil];
then use following methods
-(void)reloadData
{
[_nextAppointmentTableView reloadData];
// [_nextAppointmentTableView reloadData];
[self loadData];
}
- (void)keyboardDidShow:(NSNotification *)notification
{
}
- (void)keyboardWillHide:(NSNotification *)notification
{
[self performSelector:@selector(reloadData) withObject:nil afterDelay:0.5];
}