Get keyDown event for an NSTextField - xcode

Question

In xcode last version, I am trying to get the keyDown event of an NSTextField.
However, despite following multiple tutorials on the internet (delegates, controllers...), I still can't receive it.
Any easy hint for me ?
Thanks !

Answer 1

I got sick of all the non answers to do it some other way people so I put my nose down and figured out a way to make this work. This isn't using keydown event directly but it is using the keydown in the block. And the behavior is exactly what I wanted.
Subclass the text field
.h
#interface LQRestrictedInputTextField : NSTextField
.m
In the become first responder setup a local event
static id eventMonitor = nil;
- (BOOL)becomeFirstResponder {
BOOL okToChange = [super becomeFirstResponder];
if (okToChange) {
[self setKeyboardFocusRingNeedsDisplayInRect: [self bounds]];
if (!eventMonitor) {
eventMonitor = [NSEvent addLocalMonitorForEventsMatchingMask:NSKeyDownMask handler:^(NSEvent *event) {
NSString *characters = [event characters];
unichar character = [characters characterAtIndex:0];
NSString *characterString=[NSString stringWithFormat:#"%c",character];
NSArray *validNonAlphaNumericArray = #[#" ",#"(",#")",#"[",#"]",#":",#";",#"\'",#"\"",#".",#"<",#">",#",",#"{",#"}",#"|",#"=",#"+",#"-",#"_",#"?",#"#",
#(NSDownArrowFunctionKey),#(NSUpArrowFunctionKey),#(NSLeftArrowFunctionKey),#(NSRightArrowFunctionKey)];
if([[NSCharacterSet alphanumericCharacterSet] characterIsMember:character] || character == NSCarriageReturnCharacter || character == NSTabCharacter || character == NSDeleteCharacter || [validNonAlphaNumericArray containsObject:characterString ] ) { //[NSCharacterSet alphanumericCharacterSet]
} else {
NSBeep();
event=nil;
}
return event;
} ];
}
}
NSLog(#"become first responder");
return okToChange;
}
remove the event once the textfield editing ends
Also if you're using ARC I noticed you might need to assign the textview string to the stringValue. I nslog'd the stringValue and the value was retained. Without the nslog I had to assign the notification object string to the stringValue to keep it from getting released.
-(void) textDidEndEditing:(NSNotification *)notification {
[NSEvent removeMonitor:eventMonitor];
eventMonitor = nil;
NSTextView *textView=[notification object];
self.stringValue=textView.string;
}

Answer 2

You can subclass NStextField and use keyUp that works for NSTextField.
in .h
#interface MyTextField : NSTextField <NSTextFieldDelegate>
in .m
-(void)keyUp:(NSEvent *)theEvent {
NSLog(#"Pressed key in NStextField!");
}

Answer 3

Add UITextFieldDelegate to your .h like this
#interface ViewController : UIViewController <UITextFieldDelegate> {
Then you can use this to detect every key press in a text field
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
Return YES to allow the character that was pressed to be inserted into the field but you can add whatever code you need in here.