UITextField : Keyboard doesn't come up after first editing - ios

Question

I'm trying to move the my view up when keyboard appears and then down again on disappear.
The first time the keyboard appears , it works as intended . When I press 'Done' , keyboard disappears and view moves back. However , after this initial editing , clicking on the textfiled does nothing. The keyboard doesn't come up at all.
In viewDidLoad method I've written :
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardDidShow:) name:UIKeyboardDidShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardDidHide:) name:UIKeyboardDidHideNotification object:nil];
And implemented the following delegates :
- (void)keyboardDidShow:(NSNotification *)notification
{
//Assign new frame to your view
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.3];
NSDictionary* info = [notification userInfo];
CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
[self.view setFrame:CGRectMake(0,-kbSize.height,320,460)];
[UIView commitAnimations];
}
-(BOOL)textFieldShouldReturn:(UITextField *)textField {
[self.view endEditing:YES];
return NO;
}
-(void)keyboardDidHide:(NSNotification *)notification
{ [UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.3];
[self.view setFrame:CGRectMake(0,0,320,460)];
[UIView commitAnimations];
}

Answer 1

I don't recommend you to move self.view for it. Put all subviews on scrollview or tableview and assign this class on it.
https://github.com/michaeltyson/TPKeyboardAvoiding

Answer 2

You need to implement resignFirstResponder on your UITextfield so that the keyboard can be launched again. In your implementation what you could do is add the following line to your textFieldShouldReturn method:
[textfield resignFirstResponder];

Answer 3

If you change your -textFieldShouldReturn method to the following it should work.
-(BOOL)textFieldShouldReturn:(UITextField *)textField {
[textField resignFirstResponder];
return YES;
}
Per the documentation:
By returning NO, you could prevent the user from switching to another control
Returning NO, keeps focus on the control, so I'm assuming that the next time you tap the textFiled nothing happens because the system thinks that control is already focused.