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Packaging app for iOS

Introduction​

Flet CLI provides flet build ipa command that allows packaging Flet app into an iOS archive bundle and IPA for distribution.

note

The command can be run on macOS only.

Prerequisites​

Native Python packages​

Native Python packages (vs "pure" Python packages written in Python only) are packages that partially written in C, Rust or other languages producing native code. Example packages are numpy, cryptography, lxml, pydantic.

When packaging Flet app for iOS with flet build command such packages cannot be installed from PyPI, because there are no wheels (.whl) for iOS platform.

Therefore, you have to compile native packages for iOS on your computer before running flet build command.

Work in progress

We are actively working on automating the process described below - it's #1 item in our backlog.

Flet uses Kivy for iOS to build Python and native Python packages for iOS.

To build your own Python distributive with custom native packages and use it with flet build command you need to use toolchain tool provided by Kivy for iOS.

toolchain command-line tool can be run on macOS only.

Start with creating a new Python virtual environment and installing kivy-ios package from Flet's fork as described here:

pip install git+https://github.com/flet-dev/python-for-ios.git

Run toolchain command with the list of packages you need to build, for example to build numpy:

toolchain build numpy

NOTE: The library you want to build with toolchain command should have a recipe in this folder. You can submit a request to make a recipe for the library you need or create your own recipe and submit a PR.

You can also install package that don't require compilation with pip:

toolchain pip install flask

This case you don't need to include that package into requirements.txt of your Flet app.

When toolchain command is finished you should have everything you need in dist directory.

Get the full path to dist directory by running realpath dist command.

In the terminal where you run flet build ipa command to build your Flet iOS app run the following command to store dist full path in SERIOUS_PYTHON_IOS_DIST environment variable:

export SERIOUS_PYTHON_IOS_DIST="<full-path-to-dist-directory>"

Build your app by running flet build ipa command.

You app's bundle now includes custom Python libraries.

flet build ipa​

Build an iOS archive bundle and IPA for distribution (macOS host only).

Work in progress

Creating of an iOS package, suitable for running on a device or publishing to AppStore is, in general, a complex process with a lot of moving parts. Let us know if it worked or didn't work for your particular case and there are some changes required into Flutter project template.

To successfully generate IPA you should provide correct values for the following arguments:

  • --org - organization name in reverse domain name notation, e.g. com.mycompany (default is com.flet). The value is combined with --project and used as an iOS and Android bundle ID.
  • --project - project name in C-style identifier format (lowercase alphanumerics with underscores) used to build bundle ID and as a name for bundle executable. By default, it's the name of Flet app directory.
  • --team - team ID to locate provisioning profile. If no team ID provided a unsigned iOS archive will be generated.