Is there a simpler API for descending the accessibility object hierarchy?

Question

I am thinking about using the Accessibility API to automate some UI tasks, but I am finding that writing the code to descend the accessibility object hierarchy requires a lot of code and is prone to accidental memory leaks if I forget to call CFRelease(). For example, here is code that I wrote to look for an AXSplitGroup child of an accessibility object:

//AXError axErr;
//CFTypeRef typeRef;

AXUIElementRef axSplitGroup = NULL;
{
    CFIndex objectChildrenCount;
    axErr = AXUIElementGetAttributeValueCount(axObject, kAXChildrenAttribute, &objectChildrenCount);
    assert(kAXErrorSuccess == axErr);
    CFArrayRef objectChildren;
    axErr = AXUIElementCopyAttributeValues(axObject, kAXChildrenAttribute, 0, objectChildrenCount, &objectChildren);
    assert(kAXErrorSuccess == axErr);
    assert(CFArrayGetCount(objectChildren) == objectChildrenCount);

    for (CFIndex i = 0; i < objectChildrenCount; ++i) {
        AXUIElementRef objectChild = CFArrayGetValueAtIndex(objectChildren, i);
        axErr = AXUIElementCopyAttributeValue(objectChild, kAXRoleAttribute, &typeRef);
        assert(kAXErrorSuccess == axErr);
        assert([(__bridge id)typeRef isKindOfClass:[NSString class]]);
        CFStringRef role = (CFStringRef)typeRef;
        if (kCFCompareEqualTo == CFStringCompare(role, kAXSplitGroupRole, 0)) {
            axSplitGroup = objectChild;
            i = objectChildrenCount - 1;
        }
        CFRelease(role);
    }
    CFRelease(objectChildren);

    assert(axSplitGroup);
}

Originally I was wondering (read: hoping) that Apple provided an API that would allow XPath-like expressions to be evaluated on the accessibility object hierarchy to retrieve accessibility object(s) of interest, but from some searching, I don't think that this exists.

Is there another standard API that can be used to iterate the accessibility object hierarchy without so much code?

Answer 1

Your best option is to adopt Apple's UI Automation, which allows you to query and interact with elements in the accessibility hierarchy via Instruments and a JavaScript API. This is the preferred technique for interface automation. You will directly benefit from any work you've already done to adopt UIAccessibility.