CocoaDev

NSTextField responds to TAB to move to next field on the layout. How easy is it to make it respond to RETURN ? Or to respond to both Return OR tab ?

Database users often instinctively hit RETURN to leave a field. Others are used to TAB.

I�d like to be able to manage 2 responder chains: the normal one, accessed by hitting Tab or Shift-Tab and a custom one triggered by hitting Return or Shift-Return.

The Tab chain might be set up in IB. And I�m trying to handle navigation too when the user exits the textField by hitting Return. I added some code in the Action method of the field but I can never make first responder the textField I want�

So I tried to override - (BOOL)textView:(NSTextView *)aTextView doCommandBySelector:(SEL)aSelector. I can catch that the event is NSTabCharacter for example but then when attempting to do aTextView window] selectKeyViewFollowingView:aTextView]; nothing happens� Also [[NSLog(@”= NSTabCharacter nextKey = %@”, [aTextView nextValidKeyView]); returns null even if the responder chain and the initial first responder were set in IB.

So here is my question: Has anyone done this before and is able to submit a How-To?? What would be the better strategy: the action method or what else?

Also, if we use the action method, how (and when) do we check for Shift-Return instead of Return?

God alone knows why you might want to do this. Two responder chains is terribly non-standard, and no one – including the full keyboard access and speech recognition features – will know about it.

That said, I suggest you do the first responder like Apple does the first responder. Make a subclass of NSWindow and intercept the return and shift-return events at that level. NSWindow manages events dispatch and focus.

But in which method should I intercept those events?? And how??

[I actually have some textfields and I just want to be able to go through them tabbing or to cycle through only some of them if I decide to press Return.]

So, it works with the code below� (Shift-Return doesn�t work, though�)

I made 2 columns of 4 texFields and am now able to tab horizontally through them (normally using Tab: 0-1-2-3-4-5-6-7-0�) or vertically (using Return: 0-2-4-6-0� or 1-3-5-7-1�).

I created a custom object that stores every TF�s next and previous responder. An array of such objects is build in the controller�s awakeFromNib. You just cycle through that array to find the current view�s next “return-responder”, recursively if it turns up to be invisible�

The custom object .h:

#import <Foundation/Foundation.h>

@interface ResponderObject : NSObject {

NSView * resp;
NSView * previousResp;
NSView * nextResp;

}

// Accessor Methods

• (NSView*)resp;

• (void)setResp:(NSView*)aResp;

• (NSView*)previousResp;

• (void)setPreviousResp:(NSView*)aResp;

• (NSView*)nextResp;
• (void)setNextResp:(NSView*)aResp;

@end

Controller.h:

#import <Foundation/Foundation.h>

@interface Controller : NSObject {

IBOutlet NSTextField * tf0;
IBOutlet NSTextField * tf1;
IBOutlet NSTextField * tf2;
IBOutlet NSTextField * tf3;

IBOutlet NSTextField * tf4;
IBOutlet NSTextField * tf5;
IBOutlet NSTextField * tf6;
IBOutlet NSTextField * tf7;

NSArray * respChainArray; // Our own responder chain! }

• (IBAction)vertTab:(id)sender;

@end

Controller.m:

#import “Controller.h” #import “ResponderObject.h”

@implementation Controller

• (void)awakeFromNib { int i;

  // Array to cycle through all the textFields IBOutlets. NSArray * tfArray = [[NSArray alloc] initWithObjects: tf0, tf1, tf2, tf3, tf4, tf5,tf6, tf7, nil];

  // Set Action, Target and sendActionOn for the tFs. for (i = 0; i <= 7; i++) { tfArray objectAtIndex:i] setAction:@selector(vertTab:)]; [[tfArray objectAtIndex:i] setTarget:self]; [[[tfArray objectAtIndex:i] cell]setSendsActionOnEndEditing:NO]; }

  // Temporary array to fill our responder chain array with. [[NSMutableArray * tempRCArray = [[NSMutableArray alloc] init];

  for (i = 0; i <= 7; i++) { // Build our responder chain.

  FLResponderObject * theRespObj = [[FLResponderObject alloc] init];

  [theRespObj setResp:[tfArray objectAtIndex:i]];

  // Cases 0, 1, 6 and 7 to loop to the beginning/end of the column. if (i == 6) [theRespObj setNextResp:[tfArray objectAtIndex:0]]; else if (i == 7) [theRespObj setNextResp:[tfArray objectAtIndex:1]]; else [theRespObj setNextResp:[tfArray objectAtIndex:i+2]];

  if (i == 0) [theRespObj setPreviousResp: [tfArray objectAtIndex:6]]; else if (i == 1) [theRespObj setPreviousResp: [tfArray objectAtIndex:7]]; else [theRespObj setPreviousResp:[tfArray objectAtIndex:i-2]];

  [tempRCArray insertObject:theRespObj atIndex:i];

  [theRespObj release];

  }

  respChainArray = [[NSArray alloc] initWithArray:tempRCArray]; [tempRCArray release]; [tfArray release];

}

• (IBAction)vertTab:(id)sender; { // Action of the TFs to be able to “Tab Vertically” (using the return key). int i; NSView * newResp = nil;

  for (i = 0; i <= 7; i++) { // Find out our own nextResponder. if ([sender isEqualTo:respChainArray objectAtIndex:i] resp) { newResp = respChainArray objectAtIndex:i] nextResp]; break; } }

  while ([newResp isHidden]) { // While it isn�t Visible, for (i = 0; i <= 7; i++) { //take its nextResponder. if ([newResp isEqualTo:[[respChainArray objectAtIndex:i] resp) { newResp = respChainArray objectAtIndex:i] nextResp]; break; } } } [[sender window] makeFirstResponder:newResp]; }

• ([[IBAction)setTFHidden:(id)sender; { // Action for the checkboxes to make the textFields hidden. [ [sender window] contentView] viewWithTag:[sender tag setHidden:[sender state]]; }

@end