<Swing Dev> [Accessibility]Focus unable to traverse in the menubar

[Pavel Porvatov]

Hi Jing,
> Thanks Pavel,
>
>      It seems fine to me, if no other suggestions/opinions, I guess we 
> can move on with this?
Yes, we can. Could you please file a bug for the problem as well?

Thanks, Pavel
>
> On 2011/11/2 19:58, Pavel Porvatov wrote:
>> Hi Jing,
>>>
>>> Hello Anton,
>>>
>>>     Thanks for the review. I am still trying to figure out some real 
>>> case and provide more detail the customer may fail.
>>>     Anyway, I agree we'd better update the java spec to make it 
>>> clear for the customers. I'd like to know if anyone can help with that?
>> I'm not sure that javadoc changing is a good decision in this case. 
>> ContainerOrderFocusTraversalPolicy is designed for AWT, but I don't 
>> know why that policy cannot be used for Swing components as well. I 
>> see several problems:
>> 1. We cannot change javadoc of ContainerOrderFocusTraversalPolicy 
>> because of backward compatibility
>> 2. We cannot remove setFocusTraversalKeysEnabled(false) from the 
>> JMenuBar#JMenuBar() constructor because of backward compatibility
>>
>> May be the best decision is to specify, that JMenuBar creates menu 
>> with the focusTraversalKeysEnabled = false
>>
>> Regards, Pavel
>>>
>>> On 2011/10/12 20:54, Anton Tarasov wrote:
>>>> Hi Neil,
>>>>
>>>> On 10/10/2011 7:01 PM, Neil Richards wrote:
>>>>> On Mon, 2011-10-10 at 16:56 +0400, Anton Tarasov wrote:
>>>>>> Hi Neil and Jing,
>>>>>> I'm afraid that it's wrong to use ContainerOrderFocusTraversalPolicy
>>>>>> for swing components. This policy is designed for AWT.
>>>>>> JMenuBar calls setFocusTraversalKeysEnabled(false) in its ctor which
>>>>>> means that it "swallows" focus traversal keys (like TAB/SHIFT-TAB
>>>>>> etc.)
>>>>>> and so it can't be a member of a focus traversal chain. Swing's
>>>>>> default traversal policy (LayoutFocusTraversalPolicy) excludes
>>>>>> JMenuBar
>>>>>> from a focus traversal cycle. ContainerOrderFocusTraversalPolicy is
>>>>>> not "aware" about JMenuBar and so it allows it.
>>>>>>
>>>>>> So, either a default Swing policy should be used, or a custom 
>>>>>> policy.
>>>>>> At worst, ContainerOrderFocusTraversalPolicy should be overriden
>>>>>> to exclude JMenuBar from a cycle (override its accept(Component)
>>>>>> method).
>>>>>>
>>>>>> Thanks,
>>>>>> Anton.
>>>>> Hi Anton,
>>>>> Thanks for reviewing the suggestion, and for your insights into this
>>>>> scenario.
>>>>>
>>>>> > From the Javadoc, it seems that setFocusTraversalKeysEnabled() 
>>>>> is mainly
>>>>> concerned with choosing whether focus traversal key presses (normally
>>>>> TAB and SHIFT-TAB) are processed "automatically" (when 'true') or are
>>>>> delivered to the Component as key events (for the component's code to
>>>>> process "manually").
>>>>>
>>>>> (In the case of JMenuBar, it makes them come through as key 
>>>>> events, but
>>>>> doesn't do anything special to process these events, which is why 
>>>>> they
>>>>> get discarded.)
>>>>
>>>> That is right, though it doesn't directly relate to the issue we're 
>>>> talking about =)
>>>>
>>>>> Your description above, though, seems to suggest that it is generally
>>>>> undesirable for the JMenuBar to be given the focus, as all the
>>>>> Swing-aware focus traversal policies make a point of not giving 
>>>>> focus to
>>>>> JMenuBar items.
>>>>>
>>>>> If this is so, then wouldn't it make sense to call 
>>>>> setFocusable(false)
>>>>> from its constructor (too), to ensure it doesn't get focus ?
>>>>>
>>>>> Or, to put it another way, could you explain a little of the 
>>>>> reasoning
>>>>> or scenario behind why it is desirable for JMenuBar items to be
>>>>> generally focusable, even though they aren't focus-traversable ?
>>>>>
>>>>> I think such an explanation would be really helpful in clearing up my
>>>>> confusion on this point.
>>>>>
>>>>> Thanks, Neil
>>>>>
>>>>
>>>> Well, I suspect that the core of the problem is that adding 
>>>> JMenuBar as JComponent to a swing
>>>> container doesn't make much sense. Though it is not directly 
>>>> prohibited, doing so may cause
>>>> side effects like the one you've discovered. When JMenuBar is set 
>>>> properly onto a JFrame its focus
>>>> is managed by JRootPane and its focusability just isn't taken into 
>>>> account. That's may be the reason
>>>> it's not declared unfocusable. Honestly, I can't tell you exactly.
>>>>
>>>> If you do it, you probably won't make any harm, but I personally 
>>>> don't think this is a vital fix
>>>> (unless you have a good use case of the scenario you've provided). 
>>>> Anyway, this is a swing question
>>>> (I'm, as an AWT dev member, leaving the decision to swing guys).
>>>>
>>>> Thanks,
>>>> Anton.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>
>