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Call iOS APIs with pyobjus

pyobjus bridges Python and Objective-C, so your app can call the iOS frameworks and any @objc class you ship. This page shows you how to add pyobjus and call both kinds of class.

Before you begin

  • Configure your iOS app, including the mobile wheel index in extra_index_urls. The iOS pyobjus wheel resolves from that index.

Add pyobjus

  1. Add pyobjus to your dependencies:

    [project]
dependencies = [
    "kivy>=3.0.0.dev0,<4",
    "pyobjus",
]

  2. Lock the project:

    kivyforge lock -p ios

Note

pyobjus works only on iOS. Import it inside a platform check and provide a fallback, so the app still runs when you test it elsewhere. The pyobjus-deviceinfo example does this:

from kivy.utils import platform

if platform == "ios":
    from pyobjus import autoclass

Call an iOS framework class

autoclass returns a proxy for an Objective-C class. This example reads the device name and system version through UIDevice. Objective-C properties are plain attributes; NSString values come back as proxies, which you convert with UTF8String():

from pyobjus import autoclass


def nsstr(value):
    raw = value.UTF8String()
    return raw.decode("utf-8") if isinstance(raw, bytes) else str(raw)


device = autoclass("UIDevice").currentDevice()
print(nsstr(device.name))
print(nsstr(device.systemName), nsstr(device.systemVersion))

Call your own Swift shim

When you add a Swift package that exposes an @objc class, look the class up by its Objective-C runtime name. The keychain-spm example declares @objc(KeychainBridge) with class methods such as @objc(storeString:forKey:). pyobjus maps each colon in a selector to an underscore:

from pyobjus import autoclass

KeychainBridge = autoclass("KeychainBridge")
KeychainBridge.storeString_forKey_("secret", "token")
value = KeychainBridge.stringForKey_("token")

The shim framework is linked and embedded, so it loads at launch, and its load commands bring in the Swift package it wraps.

Verify

Run the app on the Simulator and confirm that the values appear:

kivyforge run -p ios --simulator

What's next