A SwiftUI-style declarative NSToolbar for macOS and Mac Catalyst.

NSToolbar has an amazing API with incredible flexibility, but I find that it can be too verbose and spread throughout your code with the use of delegates and callbacks for simpler projects and I have trouble keeping tabs on all the individual components. Even moreso if you want to use actions and bindings on the toolbar objects which just increases the amount code required for each toolbar.

Because of this, I tended to find that I wasn't putting toolbars into my (admittedly basic) apps.

I was keen to see if I could produce an API that can :-

• use a SwiftUI- style declarative style for defining the toolbar.
• provide a block-based or bindings based interaction model.
• provide basic functionality for all of the toolbar item types. For example, segmented controls, search controls.
• provide fallback for newer toolbar functionality. For example, if you want to use the new macOS 11 splitview-tracking toolbar items you'd have to litter your code with if #available(macOS 11, *) if you want/need to support 10.15 (for example).
• legacy support for minSize/maxSize toolbar items on older macOS versions (before 10.13) if needed.

This module doesn't contain the full functionality of the NSToolbar/NSToolbarDelegate, but provides a decent chunk of the core functionality.

If you're familiar with SwiftUI syntax you'll feel comfortable with the declaration style.

class MyViewController: NSViewController {
   // A binder to enable/disable the search field
   let searchEnabled = ValueBinder(true)
   // The search text binding to the content of the search toolbar item
   let searchText = ValueBinder("") { newValue in
      Swift.print("Search text is now \(newValue)")
   }
   ...
   lazy var customToolbar: DSFToolbar = {
      DSFToolbar(
         toolbarIdentifier: NSToolbar.Identifier("Core"),
         allowsUserCustomization: true
      ) {
         DSFToolbar.Item(NSToolbarItem.Identifier("item-new"))
            .label("New")
            .isSelectable(true)
            .image(ProjectAssets.ImageSet.toolbar_new_document.template)
            .shouldEnable { [weak self] in
               self?.canAddDocument() ?? false
            }
            .action { [weak self] _ in
               self?.addDocument()
            }

         DSFToolbar.Item(NSToolbarItem.Identifier("item-edit"))
            .label("Edit")
            .isSelectable(true)
            .image(ProjectAssets.ImageSet.toolbar_edit_document.template)
            .shouldEnable { [weak self] in
               self?.canEditDocument() ?? false
            }
            .action { [weak self] _ in
               self?.editDocument()
            }

         DSFToolbar.FlexibleSpace()

         DSFToolbar.Search(NSToolbarItem.Identifier("search-field"))
            .label("Search")
            .isSelectable(true)
            .bindIsEnabled(searchEnabled)
            .bindText(self.searchText)
      }
   }()
   ...
   // Attaching the window to the toolbar will make the toolbar appear
   self.customToolbar.attachedWindow = self.view.window
}

And thats it!

For the most part, you'll only really need to use DSFToolbar.Item, DSFToolbar.Group and DSFToolbar.Search to get 90+% of the toolbar functionality you'll need.

Even moreso if you target 10.15 or later, you can use DSFToolbar.Group as a segmented-style control by settings isBordered(true).

A toolbar can be marked as customisable by settings allowsUserCustomization: true in the constructor of the toolbar.

Additionally you can set or bind to the toolbar's display mode (eg. .iconAndLabel, .labelOnly) by calling displayMode() or binding using bindDisplayMode() on your DSFToolbar instance.

A toolbar item can be marked with isDefault to indicate that the item should appear on the default toolbar. An item marked as isDefault(false) will not appear initially in the toolbar, but will appear in the customization palette to allow to be added.

A toolbar item marked as isSelectable will show a selection marker when pressed. You can detect the toolbar selection change by providing a block for the onSelectionChange property.

self.customToolbar = DSFToolbar(NSToolbar.Identifier("My Toolbar")) {
      ...
   }
   .onSelectionChange { newToolbarSelection in
      // Do something when the selection changes
   }

Items which provide callbacks (for example, responses to clicks) can provide a block action to respond with as part of the declaration.

self.customToolbar = DSFToolbar(NSToolbar.Identifier("Buttons")) {
   DSFToolbar.Image(NSToolbarItem.Identifier("toolbar-image-bordered"))
      .label("Burger")
      .action { _ in
         Swift.print("Clicked burger!")
      }
   }

Capturing self in any block can create retain cycles, so make sure you [weak self] if you need to capture self within a block

Some toolbar items can request information. For example, you can pass a block that provides the enabled status of an Image item during the declaration.

Capturing self in any block can create retain cycles, so make sure you [weak self] if you need to capture self within a block

self.customToolbar = DSFToolbar(NSToolbar.Identifier("Enabled-buttons")) {
   DSFToolbar.Image(NSToolbarItem.Identifier("toolbar-image-bordered"))
      .label("Burger")
      .shouldEnable { [weak self] in
         return self?.IsBurgerMenuEnabled() ?? false
      }
      .action { _ in
         Swift.print("Clicked burger!")
      }
   }

A lot of functionality can be hooked up via bindings in order to pass information to and from a toolbar item. For example, you can hook the content of the Search item to a class variable to observe when the content of the search field changes.

This library uses DSFValueBinders to provide two-way bindings between local properties and toolbar items.

let searchText = ValueBinder("") {
   // Update the search with the new string
}
   ...
self.customToolbar = DSFToolbar("Search") {
   DSFToolbar.Search("toolbar-search-field")
      .label("Search")
      .bindSearchText(self.searchText)
   }

When you are finished with a toolbar, you need to call close() on the toolbar object. This will remove any bindings or observers or custom controls that were set up during the creation of the toolbar.

self.customToolbar.close()

You can find pre-made demos under the Demos folder

• DSFToolbar Demo: Project for Xcode 12 containing targets for macOS and macCatalyst

MIT. Use it for anything you want! Let me know if you do use it somewhere, I'd love to hear about it.

MIT License

Copyright (c) 2023 Darren Ford

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