Become first responder without animation

问题

Is there a way for a UITextField to become first responder without the animation of the keyboard? That is, make it such that the keyboard just appears?

Basically, I'm pushing a second UIViewController over the UIViewController that has the UITextField, and when that second view controller gets popped off the stack, I want the UITextField to immediately have first responder status so that when the second view controller gets popped, the user never notices the text field wasn't first responder.

Right now I have it so that when it's popped, the keyboard animates up the screen, but I don't want that to be seen.

Any ideas?

回答1:

You can use a UIView animation like so

[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.0];
[UIView setAnimationDelay:0.0];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];

[textField becomeFirstResponder];  // <---- Only edit this line

[UIView commitAnimations];

This will cause the keyboard to suddenly appear.

You can do the same but with -resignFirstResponder

Swift ..

    UIView.beginAnimations(nil, context: nil)
    UIView.setAnimationDuration(0.0)
    UIView.setAnimationDelay(0.0)
    someTextView.resignFirstResponder()
    UIView.commitAnimations()

回答2:

Just set it as the first responder in -viewDidAppear to make the user never notice the field having lost its status.

-(void)viewWillAppear:(BOOL)animated {
    if ([self isViewLoaded] && self.textField)
        [self.textField becomeFirstResponder];
        [super viewWillAppear:animated];
}

I've put a short sample project up on dropbox using this code, if you'd like it.

回答3:

I'm, mot sure what iOS version do you use or at what point do you call becomeFirstResponder Calling [textFieldReference becomeFirstResponder] in viewWillAppear: for iOS5/iOS6 seems to work just the way you wanted it to:

it's being called just before view controller will show it's view (that's if you don't handle view controller hierarchy manually) and as soon as it appears in navigation controller keyboard is already presented and text field has focus.

That said, there is no public way that I heard off that would allow to specify keyboard appearance style.

来源：https://stackoverflow.com/questions/11917026/become-first-responder-without-animation

标签

objective-c

ios

uitextfield