Skip to main content

ScalaFX MenuBars: Can I Right-align one Menu?

A question arose recently: can we move the Help menu item to the right edge of the active window?
In an earlier post, I looked at some basics of Menu-related controls in ScalaFX, and wrote some simple code for ScalaFX to create a basic menu bar that looked like this:


Our three Menus are all left-aligned, which is pretty standard in the realm of desktop applications.
So: does ScalaFX give us the controls and hooks that we need in order to adjust the alignment and push the last menu to be Right-aligned?


After browsing the ScalaFX API, the only alignment-related tools I noticed applied to the entire MenuBar. I did not notice anything that provided the ability to alter the alignment on a per-Menu basis.

Next, I wondered if we could set the horizontal-growth property on a Menu. If so, we could specify the last of the left-aligned Menus to have the highest priority for Horizontal stretching, which could push any Menus that followed it to the right edge of the MenuBar area.

The method HBox.setHgrow() is promising, but it acts on a Node in an HBox layout. Two issues: my basic menu above is not using HBox layout; and even if it were, Menu is not a descendant of Node.

MenuBar, on the other hand, does inherit from Node. So let's try using two MenuBars laid out in an HBox. Something like this:

  val menuCore = new MenuBar {
    menus = List(
      new Menu("_File") {
        mnemonicParsing = true
        items = List(
          new MenuItem("New..."),
          new MenuItem("Save")
        )
      },
      new Menu("_Edit") {
        mnemonicParsing = true
        items = List(
          new MenuItem("Cut"),
          new MenuItem("Copy"),
          new MenuItem("Paste")
        )
      }
    )
  }
  val menuHelp = new MenuBar {
    menus = List (
      new Menu("_Help") {
        mnemonicParsing = true
        items = List(
            new MenuItem("About")
        )
      }
    )
  }

   val menuAll = new HBox {
    children = List(menuCore, menuHelp)
  }
  HBox.setHgrow(menuCore, Priority.Always)  

   val wholeLayout = new VBox {
    children = List(menuAll)
  }

Previously, I had a single MenuBar with three Menu items added. Now, I have pulled the third one, the Help menu, out into a separate MenuBar object. I then created an HBox to lay them out side by side, and used HBox.setHgrow() to specify that any extra horizontal space be given to the menuCore object.

Then the whole HBox layout was added to a VBox as before. Here is the result:


Nice! That's the layout I was aiming for, with the main two Menus on the far left, and the Help Menu off by itself on the far right. And they keep that layout as the window is resized.

There is just one minor problem with this solution: while it visually looks like one big MenuBar, it is actually two MenuBars. It looks good and will behave correctly when users interact with it using mouse or touch-screen input. But keyboard input presents some navigation issues.

For example, when I hit the ALT-key, which normally activates a Menu on a MenuBar, this happens:


With two MenuBar objects, they both get activated by the ALT-key.

There are also some unexpected interactions when I use the keyboard arrow keys to navigate the Menus and MenuItems. I don't expect they will be insurmountable show-stoppers, but if I want to keep this two-MenuBar solution, I will have to do some work with keyboard events, to make sure that the navigation behaves as expected.

Labels:

Popular posts from this blog

Git Reset in Eclipse

Using Git and the Eclipse IDE, you have a series of commits in your branch history, but need to back up to an earlier version. The Git Reset feature is a powerful tool with just a whiff of danger, and is accessible with just a couple clicks in Eclipse. In Eclipse, switch to the History view. In my example it shows a series of 3 changes, 3 separate committed versions of the Person file. After commit 6d5ef3e, the HEAD (shown), Index, and Working Directory all have the same version, Person 3.0.
Read more

Scala Collections: A Group of groupBy() Examples

Scala provides a rich Collections API. Let's look at the useful groupBy() function. What does groupBy() do? It takes a collection, assesses each item in that collection against a discriminator function, and returns a Map data structure. Each key in the returned map is a distinct result of the discriminator function, and the key's corresponding value is another collection which contains all elements of the original one that evaluate the same way against the discriminator function. So, for example, here is a collection of Strings: val sports = Seq ("baseball", "ice hockey", "football", "basketball", "110m hurdles", "field hockey") Running it through the Scala interpreter produces this output showing our value's definition: sports: Seq[String] = List(baseball, ice hockey, football, basketball, 110m hurdles, field hockey) We can group those sports names by, say, their first letter. To do so, we need a disc
Read more

Java 8: Rewrite For-loops using Stream API

Java 8 Tip: Anytime you write a Java For-loop, ask yourself if you can rewrite it with the Streams API. Now that I have moved to Java 8 in my work and home development, whenever I want to use a For-loop, I write it and then see if I can rewrite it using the Stream API. For example: I have an object called myThing, some Collection-like data structure which contains an arbitrary number of Fields. Something has happened, and I want to set all of the fields to some common state, in my case "Hidden"
Read more

How to do Git Rebase in Eclipse

This is an abbreviated version of a fuller post about Git Rebase in Eclipse. See the longer one here : One side-effect of merging Git branches is that it leaves a Merge commit. This can create a history view something like: The clutter of parallel lines shows the life spans of those local branches, and extra commits (nine in the above screen-shot, marked by the green arrows icon). Check out this extreme-case history:  http://agentdero.cachefly.net/unethicalblogger.com/images/branch_madness.jpeg Merge Commits show all the gory details of how the code base evolved. For some teams, that’s what they want or need, all the time. Others may find it unnecessarily long and cluttered. They prefer the history to tell the bigger story, and not dwell on tiny details like every trivial Merge-commit. Git Rebase offers us 2 benefits over Git Merge: First, Rebase allows us to clean up a set of local commits before pushing them to the shared, central repository. For this
Read more

Code Coverage in C#.NET Unit Tests - Setting up OpenCover

The purpose of this post is to be a brain-dump for how we set up and used OpenCover and ReportGenerator command-line tools for code coverage analysis and reporting in our projects. The documentation made some assumptions that took some digging to fully understand, so to save my (and maybe others') time and effort in the future, here are my notes. Our project, which I will call CEP for short, includes a handful of sub-projects within the same solution. They are a mix of Web APIs, ASP MVC applications and Class libraries. For Unit Tests, we chose to write them using the MSTest framework, along with the Moq mocking framework. As the various sub-projects evolved, we needed to know more about the coverage of our automated tests. What classes, methods and instructions had tests exercising them, and what ones did not? Code Coverage tools are conveniently built-in for Visual Studio 2017 Enterprise Edition, but not for our Professional Edition installations. Much less for any Commun
Read more