Changing the frame of an inputAccessoryView in iOS

Question

Long time lurker - first time poster!

I am having an issue while recreating a bar with a UITextView like WhatsApp does it.

I am using a custom UIView subclass, and lazily instantiating it on:

- (UIView *)inputAccessoryView

and returning YES on:

- (BOOL)canBecomeFirstResponder

Now, I want to change the size of the inputAccessoryView when the UITextView grows in size. On iOS 7, I would simply change the size of the frame of said view - and not it's origin -, and then call reloadInputViews and it would work: the view would be moved upwards so that it is fully visible above the keyboard.

On iOS 8, however, this does not work. The only way to make it work is to also change the origin of the frame to a negative value. This would be fine, except it creates some weird bugs: for example, the UIView returns to the 'original' frame when entering any text.

Is there something I am missing? I am pretty certain WhatsApp uses inputAccessoryView because of the way they dismiss the keyboard on drag - only in the latest version of the app.

Please let me know if you can help me out! Or if there is any test you would like me to run!

Thank you! :)

BTW, here is the code I am using to update the height of the custom UIView called composeBar:

// ComposeBar frame size
CGRect frame = self.composeBar.frame;
frame.size.height += heightDifference;
frame.origin.y -= heightDifference;
self.composeBar.frame = frame;
[self.composeBar.textView reloadInputViews]; // Tried with this
[self reloadInputViews];                     // and this

Edit: full source code is available @ https://github.com/manuelmenzella/SocketChat-iOS

Answer 1

The issue is that in iOS 8, an NSLayoutConstraint that sets the inputAccessoryView's height equal to its initial frame height is installed automatically. In order to fix the layout problem, you need to update that constraint to the desired height and then instruct your inputAccessoryView to lay itself out.

- (void)changeInputAccessoryView:(UIView *)inputAccessoryView toHeight:(CGFloat)height {
    for (NSLayoutConstraint *constraint in [inputAccessoryView constraints]) {
        if (constraint.firstAttribute == NSLayoutAttributeHeight) {
            constraint.constant = height;
            [inputAccessoryView layoutIfNeeded];
            break;
        }
    }
}

Answer 2

Here's a complete, self-contained solution (thanks @JohnnyC and @JoãoNunes for pointing me in the right direction, @stigi for explaining how to animate intrinsicContent changes):

class InputAccessoryView: UIView {

    // InputAccessoryView is instantiated from nib, but it's not a requirement
    override func awakeFromNib() {
        super.awakeFromNib()        
        autoresizingMask = .FlexibleHeight
    }

    override func intrinsicContentSize() -> CGSize {
        let exactHeight = // calculate exact height of your view here
        return CGSize(width: UIViewNoIntrinsicMetric, height: exactHeight)
    }

    func somethingDidHappen() {
        // invalidate intrinsic content size, animate superview layout        
        UIView.animateWithDuration(0.2) {
            self.invalidateIntrinsicContentSize()
            self.superview?.setNeedsLayout()
            self.superview?.layoutIfNeeded()
        }
    }
}

Answer 3

frist, get inputAccessoryView and set nil

UIView *inputAccessoryView = yourTextView.inputAccessoryView;
yourTextView.inputAccessoryView = nil;
[yourTextView reloadInputViews];

then set frame and layout

inputAccessoryView.frame = XXX
[inputAccessoryView setNeedsLayout];
[inputAccessoryView layoutIfNeeded];

last set new inputAccessoryView again and reload

yourTextView.inputAccessoryView = inputAccessoryView;
[yourTextView reloadInputViews];