UIView in iOS 8 Not Moving up when a UITextFiled Editing Begins

I have written the below Logic for moving a view upwards when a textfiled begins its editing.It is working fine in iOS 7 but it is not working in iOS 8.

Code:

-(void)viewDidLoad
{
  _leagalName.delegate = self;
  _phoneNumber.delegate = self;
  _email.delegate = self;
  _contactName.delegate = self;
  _contactNumber.delegate = self;
  _password.delegate = self;
  _confirmPassword.delegate = self;
}

-(void)animateTextField:(UITextField*)textField up:(BOOL)up
{
  const float movementDuration = 0.3f; // tweak as needed
  int movement = (up ? movementDistance : -movementDistance);
  [UIView beginAnimations: @"animateTextField" context: nil];
  [UIView setAnimationBeginsFromCurrentState: YES];
  [UIView setAnimationDuration: movementDuration];
  self.sampleView.frame = CGRectOffset(self.sampleView.frame, 0, movement);
  [UIView commitAnimations];
}

-(void)textFieldDidBeginEditing:(UITextField *)textField
{
  if([textField isEqual:_leagalName])
  {
    movementDistance = 0;
    [self animateTextField:textField up:YES];
  }
  else if([textField isEqual:_phoneNumber])
  {
    movementDistance = 0;
    [self animateTextField:textField up:YES];
  }
  else if([textField isEqual:_email])
  {
    movementDistance = -40;
    [self animateTextField:textField up:YES];
  }
  else if([textField isEqual:_contactName])
  {
    movementDistance = -80;
    [self animateTextField:textField up:YES];
  }
  else if([textField isEqual:_contactNumber])
  {
    movementDistance = -110;
    [self animateTextField:textField up:YES];
  }
  else if([textField isEqual:_password])
  {
    movementDistance = -140;
    [self animateTextField:textField up:YES];
  }
  else if([textField isEqual:_confirmPassword])
  {
    movementDistance = -170;
    [self animateTextField:textField up:YES];
  }
}
- (void)textFieldDidEndEditing:(UITextField *)textField
  {
    [self animateTextField:textField up:NO];
  }
- (BOOL)textFieldShouldReturn:(UITextField *)textField
  {
    [textField resignFirstResponder];
     return YES;
  }

Can anyone please explain how i can move view upwards in iOS 8.