[Accessibility]Focus unable to traverse in the menubar (original) (raw)

Jing Lv lvjing at linux.vnet.ibm.com
Wed Nov 9 08:51:41 UTC 2011

Thanks Pavel,

  It seems fine to me, if no other suggestions/opinions, I guess we

can move on with this?

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.

More information about the swing-dev mailing list