I set scroll view offset to show text field hidden by keyboard. If the user scrolls while keyboard is show, scroll view snaps back down - ios

Question

As the title says, I have a UITextField inside a UIScrollView. When the keyboard is shown, I adjust the contentOffset of the scroll view so that the text field is hidden. The issue is if the text field is at the bottom of the scroll view. When the keyboard pops up, the scroll view adjusts as needed. But, if the user touches and scrolls the area above the keyboard, then the scroll view snaps back down. Intuitively, this makes sense because I've programatically over-scrolled the scroll view, but from a user perspective it is not nice.
What can I do about this? One thing I've thought of is to move the entire scroll view frame instead of setting the content offset. I don't know how to do this. I have the desired change in offset stored in a CGFloat. Can someone help?

Answer 1

You need to change the contentInset. The contentOffset is the current scroll position so when the user scrolls it gets reset.
An example of this can be found here: https://stackoverflow.com/a/16806736/78496

Answer 2

One thing you could do is listen to UIKeyboardWillShowNotification and UIKeyboardWillHideNotification system notifications to know when to modify the contentInset of your UIScrollView. You could do this at the viewWillAppear:
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:nil];
}
Don't forget to remove yourself as an observer too,
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}
When the keyboard will show or hide you can adjust the contentInset given the keyboard's height.
- (void)keyboardWillShow:(NSNotification *)notification {
CGRect keyboardEndFrame = [notification.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
UIEdgeInsets scrollInsetWithKeyboard = UIEdgeInsetsMake(0, 0, 0, -keyboardEndFrame.height, 0)
self.scrollView.contentInset = scrollInsetWithKeyboard; // If you have a custom inset maybe now would be a good idea to save it so you can restore it later
}
- (void)keyboardWillHide:(NSNotification *)notification {
self.scrollView.contentInset = UIEdgeInsetsZero; // Or to whatever inset you had before
}
When those two methods are fired you could also animate the contentOffset if you'd like.

Answer 3

You should use this library : https://github.com/hackiftekhar/IQKeyboardManager
It is really awesome, you have only to add this lib in your project and it will manage all your textfields. You have zero line of code to do to implement this lib, it is automatic. I use it in all my project and it works fine everywhere (for textfield in a cell, tableview, scrollview...)