CGRectOffset animation misbehaved when working with TextField - ios

Question

The task is to move the textfield up when user done editing.
Right now, I have a text field textfield in the centre of the view, and a method moveTextFieldToTheTop.
Here is the code:
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
[_textField resignFirstResponder];
return NO;
}
- (void)textFieldDidEndEditing:(UITextField *)textField
{
[self moveTextFieldToTheTop];
}
- (void)moveTextFieldToTheTop
{
[UIView animateWithDuration:0.3
animations:^{
_textField.frame = CGRectOffset(_textField.frame, 0, -100);
}];
}
Instead of moving 100px up from the centre, textfield would somehow appear 100px below the centre and move to the centre position.
I debugged the code, and find out
[_textField resignFirstResponder];; is the cause of this problem.
But I really can't find out why and how to solve this problem.
Can someone please help me?
Update
I was using auto layout when I came across this problem. If I uncheck use auto layout, problem solved.
But is there a way to solve this problem with auto layout checked?

Answer 1

With auto layout change your moveTextFieldToTheTop method with this:
- (void)moveTextFieldToTheTop
{
//TODO update _textField's constraint to move _textField 100pt up
[_textField setNeedsLayout];
[UIView animateWithDuration:0.3
animations:^{
[_textField layoutIfNeeded];
}];
}
if you are using storyboard, then connect constraint of _textField to view controller, and update the code TODO part with that constraint(you need to change constraint .const property by 100)
Update
Here is the example project with textfield, just run the example, touch on textfield to open keyboard, and then press return button on keyboard.
https://www.dropbox.com/s/x138ta2uy1z3bbo/ToolBarhighlightproblem.zip?dl=0