I have a view with keyboard notifications such as keyboardWillShow and keyboardWillHide
All the codes handles with the notification I use is taken from Apple's sample code "KeyboardAccessory"
When I first enter this view, everything works fine.
But when I return to this view from its subviews, every time I tap a button that says:
[myTextField becomeFirstResponder];
the keyboardWillShow and keyboardWillHide methods will be called twice every time.
It's really confusing,
Could anyone helps me with this?
really appreciate!
You might want to post your code.
If your methods are being called twice, most likely, you are registering for the keyboard notifications multiple times and not removing the observer when you think you are.
Add your observer in viewWillAppear: and remove it in viewWillDisappear: and see what happens.
It is called twice on iOS 8 when a custom keyboard, like SwiftKey is being shown.
On the first call, it probably prepares to show, so CGSize keyboardSize = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size; will have a keybaord height of 0.
The second call will have the correct keyboard height, so if you need to adjust content insets, you can check that the height of keyboard returned is > 0 before calculating your insets.
Also, it will be called whenever user changes keyboard.
For me, changing inputAccessoryView would fire another call of keyboardWillShow because the height of an input accessory view affects the overall keyboard height.
来源：https://stackoverflow.com/questions/8082455/keyboardwillshow-called-twice