iPad UIKeyboard Hide / Resign / Dismiss Button Event Handler? - ios

Question

Can you see the button in the bottom right of the iPad keyboard?
Well I want access to the event handler for that button, Because, I have some logic that I need to administer when specifically THAT button is pressed.
My attempted solution included using the UIKeyboardWillHideNotification notification like so:
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(hideKeyboardTapped:)
name:UIKeyboardWillHideNotification
object:nil];
However this is called everytime the keyboard is dismissed, including when search cancel button is pressed, with a gesture tap on the background, etc; all of which have slightly different logic.
So I just need to have one set of logic for when that specific "hide keyboard" button is pressed.
The UIKeyboard is activated by a UISearchBar (for those of you who need extra info).
Any help would be greatly appreciated; and I'll answer any questions you may have.

Answer 1

There is not an official, Apple-sanctioned way to do this.
If you don't mind mucking around with private classes, which could get you rejected from the App Store, there is an unsupported method. Basically, you listen for changes to the keyboard's activeKey property, and if the new active key has a name of "Dismiss-Key", then the dismiss key was tapped:
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self)
{
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardDidShow:) name:UIKeyboardDidShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
}
return self;
}
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
if ([keyPath isEqualToString:#"activeKey"])
{
id activeKey = [object valueForKey:keyPath];
NSString *keyName = [activeKey valueForKey:#"name"];
if ([keyName isEqualToString:#"Dismiss-Key"])
{
[self didTapDismissKey];
}
}
else
{
[super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
}
}
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
- (void)keyboardDidShow:(NSNotification *)notification
{
// Search for the UIKeyboardLayoutStar class, which seems to manage layout for the keyboard, and observe its activeKey property
UIWindow *topWindow = [UIApplication sharedApplication].windows.lastObject;
[self traverseViewHierarchyWithView:topWindow block:^(UIView *view, BOOL *stop) {
if ([view isKindOfClass:NSClassFromString(#"UIKeyboardLayoutStar")])
{
[view addObserver:self forKeyPath:#"activeKey" options:0 context:NULL];
}
}];
}
- (void)keyboardWillHide:(NSNotification *)notification
{
// Don't forget to remove the controller as an observer!
UIWindow *topWindow = [UIApplication sharedApplication].windows.lastObject;
[self traverseViewHierarchyWithView:topWindow block:^(UIView *view, BOOL *stop) {
if ([view isKindOfClass:NSClassFromString(#"UIKeyboardLayoutStar")])
{
[view removeObserver:self forKeyPath:#"activeKey"];
}
}];
}
- (BOOL)traverseViewHierarchyWithView:(UIView *)view block:(void (^)(UIView *, BOOL *))block
{
BOOL stop = NO;
block(view, &stop);
if (stop)
{
return YES;
}
for (UIView *subview in view.subviews)
{
if ([self traverseViewHierarchyWithView:subview block:block])
{
return YES;
}
}
return NO;
}
- (void)didTapDismissKey
{
NSLog(#"Dismiss key tapped");
}
Tested on the iOS 7 iPad simulator and it works.

Answer 2

I don't know if you can put a listener to a single button of the keyboard, but you can try to set some Booleans on the views, that can turn on/off the events that you want or don't want to handle (I would approach it like that), for example:
Add a custom notification observer/listener at the class where you
want to execute the method of the event.
Add the Apple default Keyboard Hide listener on the controller where the notification will be triggered.
Then, on the views that can trigger the event... Set the booleans to activate/deactivate the event action
#Some Other Class
-(void)viewWillAppear:(BOOL)animated{
[[NSNotificationCenter defaultCenter]addObserver:self
selector:#selector(doSomething)
name:#"doSomethingNotification"
object:nil];
}
-(void)viewWillDisappear:(BOOL)animated{
[[NSNotificationCenter defaultCenter] removeObserver:self name:#"doSomethingNotification" object:nil];
}
#Trigger Class
-(void)viewWillAppear:(BOOL)animated{
self.isNotificationNeeded = NO;
[[NSNotificationCenter defaultCenter]addObserver:self
selector:#selector(onKeyboardHide:)
name:UIKeyboardWillHideNotification
object:nil];
}
-(void)viewWillDisappear:(BOOL)animated{
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}
-(void)onKeyboardHide:(id)sender{
//When your event is Happening
if (self.isNotificationNeeded == YES) {
NSNotification *n = [NSNotification notificationWithName:#"doSomethingNotification" object:nil];
[[NSNotificationCenter defaultCenter] postNotification:n];
self.isNotificationNeeded = NO;
}
}
-(void)userClickedCancelButton{
//If this is a keyboard hide event that you don't want to trigger
self.isNotificationNeeded = NO;
}
//SearchBarDelegate
-(BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar{
self.isNotificationNeeded = YES; //If your event can happen from here
return YES;
}