How to detect keyboard frame changes when dismiss the keyboard interactively? - ios

Question

Consider this scenario, I have a textview with keyboard Dismiss interactively set in storyboard, so when user scroll down and able to dismiss keyboard interactively.
I have constraints on the textview to bottom to make sure it is always fully displayed on the view.
Current problem is, when user gradually scroll down to dismiss the keyboard, I can not detect the keyboard frame changes. I tried UIKeyboardWillHideNotification and UIKeyboardWillChangeFrameNotification, they were only called after the keyboard dismissed.
So my question is, how can we detect keyboard frame changes simultaneously when dismiss the keyboard interactively?

Answer 1

If you want to observe keyboard frame changes even when the keyboard is being dragged you can use this: https://github.com/brynbodayle/BABFrameObservingInputAccessoryView
Basically you create a placeholder input view for keyboard (which sticks to the keyboard all the time, even while dragging) and you observe it's frame changes. Those changes are being returned in a block, so you get current frame of the keyboard all the time.

Answer 2

You shouldn't change the textView height to fit all view. Instead - you should change contentInset field so your textView will stay the same height and you won't have to bother about tracking frame of the interactive keyboard.
See answer here:
How do I scroll the UIScrollView when the keyboard appears?

Answer 3

In your viewDidLoad method add these line:
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:nil];
the add these methods to your viewController
- (void)keyboardWillShow:(NSNotification *)notification
{
NSDictionary *userInfo = [notification userInfo];
CGSize keyboardSize = [[userInfo objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
[UIView animateWithDuration:0.30
delay:0.0
options:(7 << 16) // This curve ignores durations
animations:^{
self.buttonsBottomConstraint.constant = keyboardSize.height - self.footerView.bounds.size.height + 4.0;
[self.view layoutIfNeeded];
}
completion:nil];
}
- (void)keyboardWillHide:(NSNotification *)notification
{
[UIView animateWithDuration:0.30
delay:0.0
options:(7 << 16) // This curve ignores durations
animations:^{
self.buttonsBottomConstraint.constant = 0.0;
[self.view layoutIfNeeded];
}
completion:nil];
}