Intro to Global Hotkeys

[Presented at the joint meeting of CocoaHeads-NYC and the New York FileMaker Developers Group, July 8, 2010. I've heavily edited this since giving the presentation. The original text was much more sparse.]

Mixed audience for this meeting

Therefore:

  • Partly an intro to global hotkeys
  • Partly a glimpse into Cocoa development, for newcomers
  • Will show two apps, one trivial and one more advanced

App One: "Hello World" of hot keys

App is called "Hotness".

  • A minimal complete app
  • Bare-bones UI with five buttons (actually a matrix of five button cells)
  • Just one Objective-C class, four methods
  • Hotkey actions are defined in five AppleScript files
  • Uses a third-party library called DDHotKey which makes registering hotkeys very simple

Cocoa patterns and techniques:

  • target-action (the button matrix has a target)
  • delegation (the application object has a delegate)
  • calling AppleScript from Cocoa
  • bringing your application to the front (see the hotkey mapping for Control-0)

App Two: more realistic

App is called "WhatKeys".

  • User can create, modify, and remove hotkey assignments
  • Hotkeys can be mapped to either an AppleScript file or AppleScript code entered directly
  • Like Hotness, uses DDHotKey
  • Uses a third-party library called ShortcutRecorder for entering and displaying keyboard shortcuts

Cocoa patterns and techniques are same as in Hotness, plus:

  • MVC ("Model-View-Controller")
    • a model class (WKHotKeyAssignment)
    • view controller and window controller ("coordinating controllers")
    • array controller ("mediating controller")
  • bindings
  • properties
  • responder chain
  • user defaults and property lists (for saving the user's hotkey assignments)
  • handling NSError

Where to get

Here are links for the source:

[UPDATE 2011-01-12: I've put the code in GitHub and changed the above links accordingly.]

To compile the example code you'll need Apple's Developer Tools, which you can get for free here (requires registration). After installing the Dev Tools, double-click an xcodeproj file to open the project in Xcode.

[UPDATE 2001-02-09: This post used to be a WordPress "page", but I decided it should really be a regular blog post, so here it is.]

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