PyObjC Framework - Cocoa

Warnings

• breaking PyObjC 12.0 dropped support for Python 3.9. Ensure your Python environment is 3.10 or later.
  Fix: Upgrade Python to 3.10 or a newer supported version (e.g., `pyenv install 3.10.x` and `pyenv local 3.10.x`).
• breaking PyObjC 11.0 dropped support for Python 3.8. Python 3.9 and later were supported in this version.
  Fix: Upgrade Python to 3.9 or a newer supported version.
• breaking The `IMServicePlugIn` framework bindings were removed in PyObjC 10.0, as the framework was deprecated in macOS 10.13 and removed in macOS 14.
  Fix: Migrate away from the `IMServicePlugIn` framework to supported macOS APIs if your application relies on instant messaging services.
• breaking Changes in PyObjC 10.3 initially prevented the use of `__init__` when a user implemented `__new__`. While partially re-enabled in 10.3.1 for custom `__new__` implementations, classes relying on the `__new__` provided by PyObjC still cannot use `__init__`.
  Fix: Review classes with custom `__new__` and `__init__` for compatibility; avoid using `__init__` for classes relying on the default PyObjC `__new__`.
• breaking PyObjC 11.1 aligned its behavior with `clang`'s Automatic Reference Counting (ARC) documentation for initializer methods. Methods in the 'init' family now correctly steal a reference to `self` and return a new reference.
  Fix: Applications interacting with Objective-C initializer methods may need to review their memory management assumptions, though for most Python users, this change makes PyObjC more compliant with underlying Objective-C semantics.
• gotcha Key-Value Observing (KVO) with Python collections (lists, dictionaries) is not automatically supported. For instance variables that will be observed and contain a sequence or mapping, use `NSMutableArray` or `NSMutableDictionary` instances instead of Python lists or dictionaries.
  Fix: Replace Python lists with `NSMutableArray` and Python dicts with `NSMutableDictionary` for KVO-observed attributes.
• gotcha Developing PyObjC applications requires Xcode Command Line Tools to be installed on macOS for building and compilation.
  Fix: Install Xcode Command Line Tools by running `xcode-select --install` in the terminal.

Install

• pip install pyobjc-framework-cocoa Install stable version

Imports

• Foundation

  import Foundation

  Imports the Foundation framework, providing basic Objective-C classes like NSObject, NSDate, etc.
• AppKit

  import AppKit

  Imports the AppKit framework, essential for building macOS graphical user interfaces.
• objc

  import objc

  Imports the core PyObjC bridge module, providing utilities and decorators like objc.IBOutlet and objc.IBAction.
• PyObjCTools

  from PyObjCTools import AppHelper

  Provides various utility functions and classes for PyObjC development, such as AppHelper for running Cocoa event loops.

Quickstart

This simple example demonstrates importing and using a basic class (NSDate) and a function (NSLog) from the Foundation framework, showing direct interaction with Objective-C APIs via PyObjC.

import Foundation
import objc

def main():
    print(f"Current date and time: {Foundation.NSDate.date()}")
    Foundation.NSLog("Hello from PyObjC!")

if __name__ == "__main__":
    main()