Supporting the Mac OS menubar in JavaFX

[Jim Graham]

What happens when the last window closes and a "native" Mac app would 
still have a menubar?  Where do you find the first menubar marked native 
when there are no stages or scenes to search?

Also, most of the stages in a single application would tend to have the 
same skeleton of the menu bar with only minor variations.

Those 2 reasons were why I was proposing adding an app-global menu 
skeleton in the Application object - so it could be there when there are 
no windows open, and also to share the specification of the base menu 
structure between multiple windows in an app...

			...jim

On 12/14/11 3:31 PM, Jonathan Giles wrote:
> Hi All,
>
> Here's an update from the UI controls team as to how we see the native
> Mac OS menubar support working. Your thoughts are appreciated.
>
> After discussing it again today, we think that the approach suggested by
> Richard in an earlier email in this thread makes the best sense, in
> terms of modularity and code cleanliness. I'll explain this further
> shortly...
>
> The thinking is to add a new property to javafx.scene.control.MenuBar.
> We haven't settled on a name, but it's something along the lines of
> 'native', 'global', 'globalMenuBar', 'screenMenuBar', or
> 'applicationMenuBar'. Whatever property name we use, we'll expand it out
> to have the usual set*/get*/*property methods. This would be the only
> public API we end up adding for native menubar support. For the
> remainder of this email I refer to this property as 'native'.
>
> This property will by default be true, indicating that on platforms
> where we support native integration, it'll happen by default.
>
> On a platform that supports native integration, we'll find the 'first'
> MenuBar in the scene that has the 'native' property set to true. We
> can't guarantee that we'll find necessarily the physically top-most
> MenuBar as that is really a matter of how the scenegraph is laid out. Of
> course, this is only a problem in situations where the scene contains
> multiple MenuBars where 'native' is true in more than one of them, which
> we hope won't often be the case. If a Scene does have multiple MenuBars
> with 'native' set to true, the behaviour is undefined. If the wrong
> MenuBar is made native, you can help provide a hint by setting 'native'
> to false in the relevant place(s).
>
> We'll also hook into the Stage and listen to the relevant events, such
> that when a Stage gains focus, we'll switch in any native menubars found
> in the scene of that stage. If no relevant MenuBar is found, then we can
> either retain the MenuBar from the previous stage, or null it out. I'm
> going to assume the former is by far going to win this vote, but feel
> free to surprise me.
>
> Using this approach, developer code should be cleaner. Your user
> interface should position a MenuBar where it makes sense for your
> application, regardless of the operating system (normally at the very
> top of your scene). On platforms where native integration is supported,
> the JavaFX-rendered MenuBar will not be rendered (although it'll likely
> remain in the scenegraph as a no-op control). If the 'native' property
> changes, we'll flick between the native and JavaFX-rendered MenuBar as
> expected. This approach means there is no operating system dependent
> code in your user interface.
>
> As I mentioned - we're totally open to discussion on any of these
> points. Any thoughts?
>
> -- Jonathan
>
> On 10/12/2011 8:56 a.m., Jonathan Giles wrote:
>> Hi all,
>>
>> One of the things we're planning to support in JavaFX 2.1 is the
>> native Mac OS menubar. This email is intended primarily to discuss the
>> API one expects to see to set a MenuBar in the native Mac OS menubar
>> area. Your feedback is sought and will be very much appreciated.
>>
>> The current thinking is that Application feels like the right place to
>> specify a global, application-wide javafx.scene.control.MenuBar on. It
>> could be assumed that if a developer were to set this property, and
>> the operating system upon which the end-user was running the JavaFX
>> application was Mac OS, that the menubar will be displayed using the
>> native Mac OS menubar. Of course, if a developer wants a
>> cross-platform look and feel, they could just place the MenuBar in the
>> stage as per usual and it would display as it currently does. This
>> approach opens up a number of questions and issues:
>>
>> 1) What happens in the case of the end-user being on Windows? Is the
>> Application.MenuBar ignored, or is it automagically added to the main
>> Stage? (I would argue for totally ignoring it....but that leads to the
>> next point).
>> 2) This approach means there needs to be operating specific code in
>> the UI to test whether a non-native MenuBar should be added (in the
>> case of Windows, for example). This starts to clutter the UI code, and
>> without careful consideration by the developer may result in needing
>> to duplicate their MenuBar code. Is there a better approach?
>>
>> Another place to specify a MenuBar would be on Stage, rather than (or
>> in addition to), Application. Having a MenuBar property on Stage would
>> allow for the MenuBar to change based on the currently focused Stage -
>> but I'm not certain this is desirable or even the expected behaviour
>> of Mac OS. Therefore, I'm thinking that this is not likely to happen
>> unless we hear otherwise.
>>
>> Like I said, we're at a very early exploration point in this process.
>> The controls team is very keen to hear feedback from the community, as
>> well as from the owners of the Application API, and the Mac OS experts
>> on this list.
>>
>> Thanks,
>> -- Jonathan