Blog: Tap into native Android and iOS APIs with Pyjnius and Pyobjus (#394)

* Create 2025-01-20-access-native-android-ios.md

* PyJnius

* Pyobjus

* Intro

Author: FeodorFitsner

blog/2025-02-23-tap-into-native-android-and-ios-apis-with-pyjnius-and-pyobjus.md

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+---
+slug: tap-into-native-android-and-ios-apis-with-Pyjnius-and-pyobjus
+title: Tap into native Android and iOS APIs with Pyjnius and Pyobjus
+author: Feodor Fitsner
+author_title: Flet founder and developer
+author_url: https://github.com/FeodorFitsner
+author_image_url: https://avatars0.githubusercontent.com/u/5041459?s=400&v=4
+tags: [releases]
+---
+
+When building mobile apps with Flet, you may need to interact directly with platform-specific APIs. Whether it’s accessing system information, managing Bluetooth devices, or working with user preferences, **Pyjnius** and **Pyobjus** by Kivy provide a seamless way to bridge Python with Java (for Android) and Objective-C (for iOS).
+
+You can now integrate both Pyjnius and Pyobjus into your Flet apps! 🚀
+
+<!-- truncate -->
+
+## Pyjnius for Android
+
+Pyjnius is a Python library for accessing Java classes using the **Java Native Interface** (JNI).
+
+### Adding to a project
+
+Add `pyjnius` dependency for Android builds only (other settings in `pyproject.toml` were omitted for brevity):
+
+```toml
+[project]
+name = "pyjnius_demo"
+version = "0.1.0"
+dependencies = [
+  "flet==0.27.1"
+]
+
+[tool.flet.android]
+dependencies = [
+  "pyjnius"
+]
+```
+
+### Usage examples
+
+Here are some example of how Pyjnius can be used in your Flet Android app.
+
+#### Getting Android OS details
+
+```python
+from jnius import autoclass
+
+# Get Build and Build.VERSION classes
+Build = autoclass('android.os.Build')
+Version = autoclass('android.os.Build$VERSION')
+
+# Get OS details
+device_model = Build.MODEL
+manufacturer = Build.MANUFACTURER
+brand = Build.BRAND
+hardware = Build.HARDWARE
+product = Build.PRODUCT
+device = Build.DEVICE
+os_version = Version.RELEASE
+sdk_version = Version.SDK_INT
+```
+
+#### Listing Bluetooth devices
+
+```python
+from jnius import autoclass
+
+# Get BluetoothAdapter instance
+BluetoothAdapter = autoclass('android.bluetooth.BluetoothAdapter')
+bluetooth_adapter = BluetoothAdapter.getDefaultAdapter()
+
+if bluetooth_adapter is None:
+    print("Bluetooth not supported on this device")
+else:
+    if not bluetooth_adapter.isEnabled():
+        print("Bluetooth is disabled. Please enable it.")
+    else:
+        print("Bluetooth is enabled.")
+
+        # Get paired devices
+        paired_devices = bluetooth_adapter.getBondedDevices()
+        for device in paired_devices.toArray():
+            print(f"Device Name: {device.getName()}, MAC Address: {device.getAddress()}")
+```
+
+### Accessing the Activity
+
+App main activity instance can be retrieved with the following code:
+
+```python
+import os
+from jnius import autoclass
+
+activity_host_class = os.getenv("MAIN_ACTIVITY_HOST_CLASS_NAME")
+assert activity_host_class
+activity_host = autoclass(activity_host_class)
+activity = activity_host.mActivity
+```
+
+Heck, you can basically call any Android API using Pyjnius - endless posibilities!
+
+Check complete [Flet Pyjnius example](https://github.com/flet-dev/python-package-tests/tree/main/Pyjnius).
+
+For more Pyjnius examples and API refer to the [Pyjnius Documentation](https://Pyjnius.readthedocs.io/en/latest/quickstart.html).
+
+...or just use ChatGPT (or your favorite LLM) to get more ideas and solutions! 😅
+
+## Pyobjus for iOS
+
+Pyobjus is a library for accessing Objective-C classes as Python classes using Objective-C runtime reflection.
+
+### Adding to a project
+
+Add `pyobjus` dependency for iOS builds only (other settings in `pyproject.toml` were omitted for brevity):
+
+```toml
+[project]
+name = "Pyjnius"
+version = "0.1.0"
+dependencies = [
+  "flet==0.27.1"
+]
+
+[tool.flet.ios]
+dependencies = [
+  "pyobjus"
+]
+```
+
+### Usage examples
+
+#### The simplest example
+
+```python
+from pyobjus import autoclass
+
+NSString = autoclass('NSString')
+text = NSString.alloc().initWithUTF8String_('Hello world')
+print(text.UTF8String())
+```
+
+#### Getting OS details
+
+```python
+from pyobjus import autoclass
+from pyobjus.dylib_manager import load_framework, INCLUDE
+
+# Load Foundation framework
+load_framework(INCLUDE.Foundation)
+
+# Get NSProcessInfo instance
+NSProcessInfo = autoclass('NSProcessInfo')
+process_info = NSProcessInfo.processInfo()
+
+# Retrieve OS version as a string
+os_version = process_info.operatingSystemVersionString.UTF8String()
+
+print(f"iOS Version: {os_version}")
+```
+
+#### Working with app user settings
+
+```python
+from pyobjus import autoclass, objc_str
+
+NSUserDefaults = autoclass('NSUserDefaults')
+
+key = "pyobjus_hello_world_key"
+value = "Hello, world!"
+
+# set key
+NSUserDefaults.standardUserDefaults().setObject_forKey_(objc_str(value), objc_str(key))
+
+# get key
+ret = NSUserDefaults.standardUserDefaults().stringForKey_(objc_str(key))
+
+assert ret.UTF8String() == value
+```
+
+Check complete [Flet Pyobjus example](https://github.com/flet-dev/python-package-tests/tree/main/pyobjus).
+
+For more Pyobjus examples and API refer to the [Pyobjus Documentation](https://pyobjus.readthedocs.io/en/latest/quickstart.html).
+
+## Plyer challenge
+
+There is a [Plyer](https://github.com/kivy/plyer) project by Kivy team which uses both Pyjnius and Pyobjus under the hood.
+
+It's not ported to Flet yet. You can either get more usage examples for [Android](https://github.com/kivy/plyer/tree/master/plyer/platforms/android) and [iOS](https://github.com/kivy/plyer/tree/master/plyer/platforms/ios) from there or help us with porting it to Flet.