Search code examples
objective-ccocoaosx-elcapitannstouchbar

cocoa build for os x 10.11 with NSTouchbar support

I know in Swift it's possible to make use of #available and objective-c doesn't support that.

Is there still a way to make an os x app which can be run on 10.11 but also supports the NSTouchbar (which starts from 10.12)?

Solution

  • #available and friends in Swift are a simplification of (and improvement on) the more complex ways of dealing with new features and backward compatibility in ObjC. If you're using ObjC, there isn't a direct equivalent to #available, so you have to fall back to those old ways. Apple's docs on such can be found in the SDK Compatibility Guide. The gist:

    1. Build your project using the latest Xcode 8.x / macOS 10.12.x (or later) SDK.

    2. Set your project's Base SDK to macOS 10.12 (or later), and its Minimum Deployment Target to 10.11.

    3. This makes the AppKit classes/methods you're looking for "weak linked", so you can check for their presence at run time. For example:

      if ([NSTouchBar class]) {
    self.touchBar = [[NSTouchBar alloc] init];
    self.touchBar.delegate = self;
    self.touchBar.defaultItemIdentifiers = @[ /*...*/ ];
    //...
}

      In macOS versions predating touch bar support, [NSTouchBar class] returns nil, so none of the touch bar usage happens. In versions with touch bar support, your if body executes.