Re: Minimum requirements for a NSAccessibility object?

Subject: Re: Minimum requirements for a NSAccessibility object?

From: James Dempsey <email@hidden>

Date: Wed, 23 Aug 2006 11:43:55 -0700

Delivered-to: email@hidden

Håkan,

Can you tell me a little bit more about the object that you are trying to make accessible? What is it a subclass of?

Since you are implementing the accessibility protocol from scratch, I am guessing that this object is a subelement of a custom view or control, and is not a view or cell itself.

A second question would be where does this object draw itself? Is it custom drawing within a view or control? If so, then the parent of this object needs to report it as one of its children, and needs to implement its accessibility hit testing / focus testing methods to call this object's accessibility hit testing / focus testing methods.

If you could provide a little more info about what you are doing, that would be very helpful.

You might also take a look at the following code samples, which show two different methods of making an object accessible from scratch:

http://developer.apple.com/samplecode/ImageMapExample/index.html

http://developer.apple.com/samplecode/Dicey/index.html

Thanks,

James

On Aug 23, 2006, at 6:46 AM, Håkan Waara wrote:

What's the absolutely required methods and attributes that a generic NSAccessibility object must support to show up in Accessibility Verifier and Accessibility Inspector?

Currently they simply do not show my objects (and don't really help me in determining what's missing). I'm supporting the following methods:

// general
- (id)accessibilityHitTest:(NSPoint)point;
- (BOOL)accessibilityIsIgnored;
- (id)accessibilityFocusedUIElement;

// attributes
- (NSArray*)accessibilityAttributeNames;
- (id)accessibilityAttributeValue:(NSString*)attribute;
- (BOOL)accessibilityIsAttributeSettable:(NSString*)attribute;

// actions
- (NSArray*)accessibilityActionNames;
- (NSString*)accessibilityActionDescription:(NSString*)action;
- (void)accessibilityPerformAction:(NSString*)action;

I support no actions, and no settable attributes. Here are the attributes I support:

NSAccessibilityChildrenAttribute
NSAccessibilityParentAttribute
NSAccessibilityRoleAttribute
NSAccessibilitySubroleAttribute
NSAccessibilityRoleDescriptionAttribute
NSAccessibilityFocusedAttribute
NSAccessibilitySizeAttribute
NSAccessibilityPositionAttribute
NSAccessibilityWindowAttribute

AFAICS, I support all that are listed as mandatory in the API reference, and even some more.

I wish NSAccessibility had more stricts requirements. Right now I more or less have to guess what's missing or what's wrong.

Now and then, at the most, I get a NSException about some attribute in the Xcode debugger, but unfortunately it provides no information about what attribute emitted the error.

Any tips, or ideas are most welcome.

Regards,
Håkan Waara _______________________________________________
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James Dempsey

AppKit Engineering

Apple

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References:
	>Minimum requirements for a NSAccessibility object? (From: Håkan Waara <email@hidden>)