Packaging the Applications

Each of the subdirectories inside the apps directory contains a manifest file for use with Flatpak. This describes where the application source code can be obtained from, how the application is built, the dependencies that need to be built with it, and the permissions it needs when it is run.

Building a Package

Following the instructions in Cross-Building an Application, we use flatpak-builder to build a flatpak for the application. To do this we need to install the runtime and SDK that the application depends on. These are the same as those mentioned in Setting up Flatpak for GNOME Development except that we need the ones for the aarch64 architecture:

flatpak --user install flathub org.gnome.Platform/aarch64/3.34 org.gnome.Sdk/aarch64/3.34

After installing these, build the application with flatpak-builder. For example, here is how to build the Title Bar application from the part1 directory:

flatpak-builder --arch=aarch64 --repo=myrepo _flatpak com.example.title_bar.json

The result is stored in the myrepo directory, which is a local repository. Export a binary bundle from the repository by running flatpak with the build-bundle command:

flatpak build-bundle --arch=aarch64 myrepo app.flatpak com.example.title_bar

In this case the bundle is written to the app.flatpak file. This can be copied to the phone or development board for installation.

Installing the Application

One way to install the application is to use the flatpak tool on the command line to install the binary bundle. Other more user-friendly ways are also possible.

First of all, copy the bundle to the target device and make it readable by the purism user. Then, log in to the device and ensure that the flathub remote is registered for the user:

flatpak --user remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo

Assuming that the app.flatpak file is in the current directory, install it for the user by running the install command:

flatpak --user install app.flatpak

Flatpak will resolve the dependencies of the bundle using the remote we registered and ask you if you want to install them if they are not already present. It will then install the application itself.

You can run the application using flatpak in the usual way:

flatpak run com.example.title_bar

When you are finished with the application and want to uninstall it, use the following command:

flatpak uninstall com.example.title_bar

You can also uninstall the runtime needed by the application, but it may be useful to keep it installed for future use.