A Cookiecutter template for building Python apps that will run under iOS.

This repository branch contains a template for Python 3.10. Other Python versions are available by cloning other branches of repository.

The easiest way to use this project is to not use it at all - at least, not directly. Briefcase is a tool that uses this template, rolling it out using data extracted from a pyproject.toml configuration file.

However, if you do want use this template directly...

1. Install cookiecutter. This is a tool used to bootstrap complex project templates:

   $ pip install cookiecutter
   

2. Run cookiecutter on the template:

   $ cookiecutter https://github.com/beeware/briefcase-iOS-Xcode-template --checkout 3.10
   

   This will ask you for a number of details of your application, including the name of your application (which should be a valid PyPI identifier), and the Formal Name of your application (the full name you use to describe your app). The remainder of these instructions will assume a name of my-project, and a formal name of My Project.

3. Download the Python Apple support package for iOS, and extract it into the My Project directory generated by the template. This will give you a My Project/Support directory containing a self contained Python install.

   Alternatively, you can download the Python-Apple-support project, and build your own version.

4. Add your code to the template, into the My Project/my-project/app. directory. At the very minimum, you need to have an app/<app name>/__main__.py file that defines a PythonAppDelegate class.

   If your code has any dependencies, they should be installed into the My Project/my-project/app_packages directory.

If you've done this correctly, a project with a formal name of My Project, with an app name of my-project should have a directory structure that looks something like:

My Project/
    my-project/
        app/
            my_project/
                __init__.py
                app.py (declares PythonAppDelegate)
        app_packages/
            ...
        ...
    My Project.xcodeproj/
        ...
    Support/
        ...
    briefcase.toml

You're now ready to open the XCode project file, build and run your project!

Of course, running Python code isn't very interesting by itself - you'll be able to output to the console, and see that output in XCode, but if you tap the app icon on your phone, you won't see anything - because there isn't a visible console on an iPhone.

To do something interesting, you'll need to work with the native iOS system libraries to draw widgets and respond to screen taps. The Rubicon Objective C bridging library can be used to interface with the iOS system libraries. Alternatively, you could use a cross-platform widget toolkit that supports iOS (such as Toga) to provide a GUI for your application.

Regardless of whether you use Toga, or you write an application natively, the template project will try to instantiate a UIApplicationMain instance, using a class named PythonAppDelegate as the App delegate. If a class of that name can't be instantiated, the error raised will be logged, and the Python interpreter will be shut down.

If you have any external library dependencies (like Toga, or anything other third-party library), you should install the library code into the app_packages directory. This directory is the same as a site_packages directory on a desktop Python install.