On Tuesday, December 13, 2016 at 7:50:43 AM UTC-2, Thomas Broyer wrote:
>
>
>
> On Tuesday, December 13, 2016 at 8:14:50 AM UTC+1, Julio Feferman wrote:
>>
>> I am instrumenting an application for best possible support for assistive
>> technologies (ATs) such as screen readers, using GWT's ARIA implementation.
>> I see that the CustomButton widget setEnabled() method sets the
>> aria-pressed attribute on the button element if it is enabled. This is fine
>> for a ToggleButton but wouldn't it be incorrect for a PushButton? When the
>> aria-pressed attribute is present, screen readers interpret the widget as a
>> toggle button. In the case of a push button, however, this attribute should
>> not be present, in order to allow the AT to click the widget via keyboard
>> commands, instead of toggling it.
>>
>
> From the code, it looks like it sets the aria-pressed state to either true
> or false depending on the current pressed state when enabled, and un-sets
> the state when disabled.
> The thing is, a PushButton is CustomButton, which actually is a kind of
> "toggle button". The ToggleButton makes it easier to work with by adding
> style names corresponding to the "faces", providing constructors to easily
> create such "faces", and having a boolean value corresponding to the
> "pressed" state. And the PushButton is actually one such button that is
> only "pressed" while the mouse button or keyboard key is depressed.
> This seems to be in line with the WAI ARIA spec:
> https://www.w3.org/TR/wai-aria/states_and_properties#aria-pressed, with
> the exception that most people don't see a PushButton as such a "special
> kind of toggle button"; so I'd agree with you that aria-pressed shouldn't
> be used for a PushButton (leaky abstraction).
>
> Actually, I strongly believe CustomButton and derivatives are a legacy
> that should be avoided. They're from a time where you couldn't easily style
> <button>, or <input type=checkbox> to create toggle buttons; this is no
> longer the case.
> Don't use a PushButton, use a Button instead. And I'd even say don't use a
> ToggleButton, use a Checkbox (or RadioButton) with proper styling, and
> possibly add ARIA attributes to make it "appear" like a toggle button to
> ATs too.
>
> Even though I believe those widgets should be deprecated, feel free to
> propose a patch, I'll (help) review it. I'm not sure we could come up with
> a viable patch though: CustomButton is "too abstract", and yet we don't
> want to move the ARIA handling to subclasses as that would remove it from
> existing custom widgets people could have written based on CustomButton.
> Maybe add a boolean (add constructor overloads) telling the CustomButton
> whether it's a toggle button or a command button? (that seems slightly
> wrong though, as that'd mean the onClick/onClickStart/onClickCancel could
> probably use that information too instead of relying on subclasses to
> change the button's behavior).
> No, really, the long-term solution is to deprecate at least PushButton and
> move on to Button.
>
I agree that we should perhaps switch our uses of PushButton to a Button.
However, I still believe ToggleButton is convenient for a series of use
cases. For instance, a disclosure arrow that has an untoggled/toggled face
(pointing right or down), in which case radio/checkbox are not appropriate.
I'm submitting a patch here for CustomButton that inserts aria-pressed only
in the case of (instanceof) a ToggleButton, completely removing the
attribute for PushButton without interfering with the subclasses or current
uses. The functionality would be preserved while only removing aria-pressed
from PushButton. Thank you very much for your help.
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--- CustomButton.java 2016-12-13 14:54:01.000000000 -0200
+++ CustomButtonNew.java 2016-12-13 14:51:30.000000000 -0200
@@ -749,7 +749,7 @@
if (!enabled) {
cleanupCaptureState();
Roles.getButtonRole().removeAriaPressedState(getElement());
- } else {
+ } else if (this instanceof ToggleButton) {
setAriaPressed(getCurrentFace());
}
}
@@ -925,7 +925,7 @@
setCurrentFaceElement(newFace.getFace());
addStyleDependentName(curFace.getName());
- if (isEnabled()) {
+ if (isEnabled() && this instanceof ToggleButton) {
setAriaPressed(newFace);
}
}
@@ -1102,4 +1102,3 @@
setCurrentFace(newFaceID);
}
}
-
