Programmatically discover identity of first responder - iphone

I want a UITextField to be sent the resignFirstResponder message if it is being edited and a user touches elsewhere on the screen. Since there are several text fields I need a way to programmatically determine which one is the first responder to send it the message. How can I do this? Is there some sort of global first responder object?
Thanks,
Jacob

The simplest way is to find the first responder and tell it to resignFirstResponder.

UITextField inherits from UIResponder so you can use isFirstResponder (which returns a BOOL) to query it.
if ([myTextField isFirstResponder]) {
// do stuff
}

Related

How to identify which textfield is currently first responder

If you have several text fields on the screen, and the keyboard pops up for each one when they are tapped, what if you want to programmatically hide the keyboard, or resign first responder, but you don't know which textfield to send the resignFirstResponder message to? Is there a way to identify which object/textField should get this message?
check all of your textfield call
[textfield isFirstResponder]
You could keep track of which text field is the first responder by either setting your view controller to be the delegate object of all text fields and then when your subclassed text fields gets the "becomeFirstResponder" method call, tell your view controller which text field is the current one.
Or, there's a more blunt force approach which is a category extension to "UIView":
#implementation UIView (FindAndResignFirstResponder)
- (BOOL)findAndResignFirstResponder
{
if (self.isFirstResponder) {
[self resignFirstResponder];
return YES;
}
for (UIView *subView in self.subviews) {
if ([subView findAndResignFirstResponder])
return YES;
}
return NO;
}
#end
which I got from this potentially very related question.
You Can Check Your all TextField and than Identify Easily.
[textfield isFirstResponder];
There is no public method to get the current first responder, but you can do things to still get it; The first one is obviously to keep track of this yourself. You can do this in various way and if you don't want to touch any existing class but just want it to work, a category and method swizzling will do the trick. The more cleaner solution however is to iterate through the view hierarchy and ask the views wether they are the current first responder. You can start with the root UIWindow and start iterating, or you can start with your current UIViewController's view, but keep in mind that the current first responder doesn't have to be part of your roots UIWindow view hierarchy (eg. if you have a text field inside an UIAlertView).
Try this (Swift 3):
if textField.isEditing {
textField.resingFirstResponder()
}

why override canBecomeFirstResponder?

I'm looking at TVAnimationGestures from WWDC 2010, and in the TableVieWController.m, they override canBecomeFirstResponder:
- (BOOL)canBecomeFirstResponder {
return YES;
}
Is there a reason they do this? I don't see this method called anywhere. Thanks.
So you can mark your question as answered...
They are using an UIMenuController within the sample, and in order to receive messages from that controller to your controller, you must make your controller the first responder (and accept becoming first responder via canBecomeFirstResponder.
This method is called by the Cocoa framework and not typically application to see if a controller should become the first responder. While I haven't looked at that specific example, it probably allows the table to be editable.
I needed to override canBecomeFirstResponder in a custom UIView so I could use a custom InputView and InputAccessoryView.
Custom Views for Data Input
I had to do it this way because if I used a UITextField or UITextView, a hardware keyboard would subvert the more limited on-screen keyboard.

How can I make an unknown UITextField resign first responder?

My view has two UITextFields and a UISwitch. If a user is edits a textField, and then immediately touches the switch (without pressing return), the text is left as they typed it, without AutoCorrect.
If I know which textField they were typing in, I can force the autocorrect to complete by calling [textField resignFirstResponder]. But the user could be typing in either textField, so I don't know which one to call.
How can I get around this? Is there a way of detecting which textField was being used? Or something simpler I haven't thought of?
One lovely way of doing this without having to keep track of which field is active:
// This causes the current responder (eg. an input field) to resignFirstResponder and
[self.endEditing:YES];
Replace [self.view endEditing:YES] with the below one...
[[UIApplication sharedApplication] sendAction:#selector(resignFirstResponder) to:nil from:nil forEvent:nil];
The uitextfielddelegate methods are called for the textfield on which the editing is in progress. So that way you needn't be facing the problem of detecting which text field is being edited.
So implement the uitextfielddelegate methods and assign the delegate of the text field to the class where you implement the methods and handle the responses in them.
The methods which you should be interested in are:
textFieldDidEndEditing:
Tells the delegate that editing stopped for the specified text field.
- (void)textFieldDidEndEditing:(UITextField *)textField
Parameters
textField
The text field for which editing ended.
Discussion
This method is called after the text field resigns its first responder status. You can use this method to update your delegate’s state information. For example, you might use this method to hide overlay views that should be visible only while editing.
Implementation of this method by the delegate is optional.
Availability
Available in iOS 2.0 and later.
Declared In
UITextField.h
You may keep track yourself which one is the current one, by using the textFieldDidBeginEditing delegate.

iPhone SDK: resignFirstResponder not working

For some reason, resignFirstResponder is not working. I am not sure why? I have tried to call it from textFieldDidEndEditing and nothing happens. A NIB is being used and each's delegate is pointing to files owner.
What needs to be done to get the keyboard to dismiss?
Thanks.
Don't use -textFieldDidEndEditing. That's called after the text field resigns firstResponder status, which is what you're trying to use it as a hook to make happen. Cart before horse, chicken-and-egg kind of problem.
Instead use -textFieldShouldReturn to get triggered when the return key is pressed (and remember to return YES; from that.) Also float a clear custom button behind the elements of the view and handle a "background tap" that goes through all the text fields on your view and resigns first responder on the lot of them.
actually you should return NO so that the text field does not begin editing at all. If it does, the firstresponder gets set and the keyboard pops up again.
Make sure your setting your delegates for the textfield.
myTextField.delegTe = self;
And you are using in your header:
<UITextFieldDelegate>
EDIT:
Try:
if(textField == myTextField){
[textField resignFirstResponder];
}

Is there a NSNotification for objects that become first resoponder?

Is there a NSNotification for objects that become first responder.
Like NSNotification that give me the UITextfield that cause the keyboard to pop up?
Check UITextFieldTextDidBeginEditingNotification, the textField that started editing is in notification's object property.
There're also UIKeyboardWillShowNotification and UIKeyboardDidShowNotification notifications
Another option is to have your view controller be a delegate to the UITextField. UITextFieldDelegate has a textFieldDidBeginEditing: method.
No, But you could check it manually by using "IsFirstResponder" (BOOL)..
Can you explain a little bit more what you want to accomplish? Maybe there is a way to use another notification.