Supporting the Mac OS menubar in JavaFX

[steve.x.northover at oracle.com]

Hey Jonathan and all,

Are we also the global Mac menu bar also on the table or should we just 
defer that?

Steve

On 14/12/2011 7:26 PM, Jim Graham wrote:
> 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