Showing keyboard via keyboardFrameWillChange causes table data to scroll out of view - ios

Question

Been struggling for about 3 days getting an implementation of a scrollable keyboard working. Here's what I have:
UIViewController with the following hierarchy:
The above diagram shows that I have a messaging style UITableView + "dockable" UIView with a textview and send button embedded in View->ScrollView->ContentView.
In viewWillAppear:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardFrameDidChange:) name:UIKeyboardWillChangeFrameNotification object:nil];
And keyboardFrameWillChange implemented:
- (void)keyboardFrameWillChange:(NSNotification *)notification
{
CGRect endFrame = [[notification.userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
NSTimeInterval duration = [[notification.userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
UIViewAnimationCurve curve = [[notification.userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] unsignedIntegerValue];
UIViewAnimationOptions options = (curve << 16) | UIViewAnimationOptionBeginFromCurrentState;
CGRect newFrame = self.view.frame;
newFrame.origin.y = endFrame.origin.y - newFrame.size.height;
[UIView animateWithDuration:duration delay:0 options:options animations:^{
self.view.frame = newFrame;
} completion:nil];
}
Which gives me an almost completely functional show and hide of the keyboard just from using keyboardFrameWillChange. This includes setting Keyboard drag dismissal on the storyboard.
I'm having one issue though: the entire view (whatever view that is) is being shifted, so if there are only a few items in the tableview, my code scrolls the top part of the view out of the way so I can no longer see them.
I have tried resizing the tableview since what I believe is happening is the scrollview is scrolling the full sized tableview out of the way instead of the tableview being resized. I have a strong feeling I'm getting my views confused, but my efforts to fix this have been in vain.
FYI there are no autolayout issues and everything is attached to the proper views and such (i.e. UIView is docked below tableview and to the bottom of the parent scrollview.
How do I solve this?

Answer 1

A few suggestions that might help:
Don’t change both frame and contentInset; changing just one should be sufficient and easier to manage. I recommend only changing contentInset.
One of UIKeyboardWillChangeFrameNotification or UIKeyboardDidChangeFrameNotification should tell you everything you need; you can deal with the keyboard in one method. The frame will go offscreen when the keyboard hides.
When you undo your changes to contentInset, put this property back to how you found it. UIViewController will automatically adjust scroll view insets to avoid the status bar, navigation bar, and toolbar or tab bar. This might be the cause of your first problem.
I know libraries are junk, but you might want to check out my DHAvoidKeyboardBehaviour. At least it’s only 34 lines of junk.
Also: you are registering for UIKeyboardWillChangeFrameNotification but your method is called keyboardFrameDidChange:. Being sloppy about the distinction between will and did will bite you one day.

Answer 2

For anyone who is interested, I solved my own question.
In keyboardFrameDidChange, I was shifting the entire tableview up to accommodate the keyboard, which was causing rows to appear off screen. What I was missing was changing the contentInsets to "resize" the tableview to fill the remaining space on the screen.
The insets became top adjusted for keyboard height and bottom adjusted for the toolbar. toolBar is the view anchored to the bottom below the tableview.
In viewWillAppear:
[super viewWillAppear:animated];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardWillBeShown:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardWillBeHidden:) name:UIKeyboardWillHideNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardFrameWillChange:) name:UIKeyboardWillChangeFrameNotification object:nil];
In viewWillDisappear:
[super viewWillDisappear:animated];
[[NSNotificationCenter defaultCenter] removeObserver:self];
Implementation of keyboardWillBeShown:
NSLog(#"Keyboard will be shown");
CGRect keyboardFrame = [[notification.userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
UIEdgeInsets contentInsets = UIEdgeInsetsMake(keyboardFrame.size.height, 0.0, toolBar.bounds.size.height, 0.0);
tableView.contentInset = contentInsets;
tableView.scrollIndicatorInsets = contentInsets;
Implementation of keyboardWillBeHidden:
NSLog(#"Keyboard will be hidden");
tableView.contentInset = UIEdgeInsetsZero;
tableView.scrollIndicatorInsets = UIEdgeInsetsZero;
Implementation of keyboardFrameWillChange:
NSLog(#"Keyboard frame will change");
NSTimeInterval duration = [[notification.userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
UIViewAnimationCurve curve = [[notification.userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] unsignedIntegerValue];
UIViewAnimationOptions options = (curve << 16) | UIViewAnimationOptionBeginFromCurrentState;
CGRect keyboardFrame = [[notification.userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
CGRect contentFrame = self.view.frame;
contentFrame.origin.y = keyboardFrame.origin.y - contentFrame.size.height;
[UIView animateWithDuration:duration delay:0 options:options animations:^{
self.view.frame = contentFrame;
} completion:nil];
Thanks to Douglas Hill for pointing me in the general direction.