Slide view upon TextField selection is only on typing - iphone

Question

I have used the demonstration code Apple has in their docs here:
http://developer.apple.com/library/ios/#documentation/StringsTextFonts/Conceptual/TextAndWebiPhoneOS/KeyboardManagement/KeyboardManagement.html#//apple_ref/doc/uid/TP40009542-CH5-SW7
I need to slide the view up when the keyboard appears from tapping a UITextField. I am using the code in the link above, Apple's own demo code for ding this and it makes sense.
However, my issue, using Apple's code virtually unchanged, the view only slides up when typing, vs actually after tapping on the text field.
In the - (void)keyboardWasShown:(NSNotification*)aNotification method, it is when this if statement is called that the view is slid up or not. Slid up if the textfield is below the keyboard, not slid up if it isn't below the keyboard.
if (!CGRectContainsPoint(aRect, activeField.frame.origin) ) {
CGPoint scrollPoint = CGPointMake(0.0, activeField.frame.origin.y-kbSize.height);
[scrollView setContentOffset:scrollPoint animated:YES];
}
Trouble is, upon tapping the text field, this if statement is skipped, the code inside it doesn't run.
I can't work it out, but it all happens in this method below. Why is it only sliding up on typing and not the initial tap?
- (void)keyboardWasShown:(NSNotification*)aNotification
{
NSDictionary* info = [aNotification userInfo];
CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);
scrollView.contentInset = contentInsets;
scrollView.scrollIndicatorInsets = contentInsets;
// If active text field is hidden by keyboard, scroll it so it's visible
// Your application might not need or want this behavior.
CGRect aRect = self.view.frame;
aRect.size.height -= kbSize.height;
if (!CGRectContainsPoint(aRect, activeField.frame.origin) ) {
CGPoint scrollPoint = CGPointMake(0.0, activeField.frame.origin.y-kbSize.height);
[scrollView setContentOffset:scrollPoint animated:YES];
}
}

Answer 1

I looked again at the Apple doc. Yuck - don't they write software for a living?? Try this instead: Remember the default position of the main view.
#interface ViewController ()
#property (assign, nonatomic) CGFloat viewOriginY;
#end
Register for keyboard notification and a tap (to dismiss first responder).
- (void)viewDidLoad
{
[super viewDidLoad];
self.viewOriginY = self.view.frame.origin.y;
NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
[center addObserver:self selector:#selector(keyboardDidShow:) name:UIKeyboardDidShowNotification object:nil];
[center addObserver:self selector:#selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
// add a tap gesture to drop first responder
UITapGestureRecognizer *tapGR = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(tapped:)];
[self.view addGestureRecognizer:tapGR];
}
Write a function to (recursively) find the first responder.
- (UIView *)firstResponderWithin:(UIView *)view {
if ([view isFirstResponder]) return view;
for (UIView *subview in view.subviews) {
UIView *answer = [self firstResponderWithin:subview];
if (answer) return answer;
}
return nil;
}
Here's the punchline: When the keyboard is shown, compute it's frame and the frame of the view that needs to be visible. Important to do this in a common coordinate system, like this vc's view. Then slide the view to make the first responder visible.
- (void)keyboardDidShow:(NSNotification *)notification {
CGRect keyboardFrameW = [[notification.userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
UIWindow *window = [[UIApplication sharedApplication] keyWindow];
CGRect keyboardFrame = [window convertRect:keyboardFrameW toView:self.view];
UIView *firstResponder = [self firstResponderWithin:self.view];
CGRect firstResponderFrame = [firstResponder.superview convertRect:firstResponder.frame toView:self.view];
// let's put the bottom of the first responder's frame just above the top of the keyboard
CGFloat firstResponderBottom = CGRectGetMaxY(firstResponderFrame);
CGFloat targetBottom = keyboardFrame.origin.y - 8.0;
CGFloat offsetY = MAX(0.0, firstResponderBottom - targetBottom);
[UIView animateWithDuration:0.3 animations:^{
self.view.frame = CGRectOffset(self.view.frame, 0.0, -offsetY);
}];
}
- (void)keyboardWillHide:(NSNotification *)notification {
[UIView animateWithDuration:0.3 animations:^{
self.view.frame = CGRectMake(0.0, self.viewOriginY, self.view.frame.size.width, self.view.frame.size.height);
}];
}
Optional - When user taps anyplace else, dismiss the keyboard.
- (void)tapped:(UITapGestureRecognizer *)gr {
UIView *firstResponder = [self firstResponderWithin:self.view];
[firstResponder resignFirstResponder];
}
Working project can be found here.
I think this idea is one ivar away from a nice category on view controller. You could import it, and invoke the setup on viewDidLoad. All it needs is a way to get the main view's default y origin without writing it in an ivar. I need to noodle on that.