Android APK crashes immediately after successful Flet build

[RIB93-stack]

Hi everyone,

I'm developing a mobile app with Python and Flet. I was finally able to build the Android APK successfully using GitHub Actions, and the APK installs correctly on my OnePlus 12R (OxygenOS 16.0.5).

However, when I try to open the app, it immediately crashes and closes. The current APK size is about 62 MB.

Package name: "com.J053.gestion_queso"

I've tried checking the logs with Logcat Reader, but unfortunately I can't get any logs from the app process.

Has anyone experienced a similar issue with Flet on Android? I'd really appreciate any help identifying what could be causing the crash. I can also provide the APK or the project files if someone is willing to take a look.

Thank you!

[ndonkoHenri]

Can you try building and testing a simple hello world flet app to see if it works on your end?

Will be nice if you could provide the link to your repo if its opensource, so we can have a closer look.

[RIB93-stack]

Hi, thanks for offering to help! Here's the link to my repo:
https://github.com/RIB93-stack/gestion-queso

Just to give context: I was trying to roll back my main branch to a stable commit (25d9cac) because some later builds were failing. I already did a git reset --hard 25d9cac and a git push origin main --force, so the branch should be at that commit now. Let me know if you spot anything off.

[ndonkoHenri]

Thanks for the repo, that made it easy to find.

Quick fix: add flet to your dependencies in pyproject.toml and rebuild:

[project]
name = "gestion-queso"
version = "1.0.0"
requires-python = ">=3.9"
dependencies = ["flet==0.25.2"]

Why it crashes: your APK doesn't contain the flet Python package. With no dependencies in pyproject.toml (and no requirements.txt), Flet 0.25.2's flet build packages your app without installing any Python packages. You can see it in your CI log: the serious_python ... package step runs without --requirements. On startup the app fails before it can report the error, so it just closes, and that's why Logcat shows nothing useful. (Since Flet 0.26.0, flet build adds flet automatically when nothing is declared, but listing it explicitly is still recommended.)

---

Recommended next step: upgrade to Flet 1.0. 0.25.2 + Flutter 3.24.5 is quite old, and current flet build installs the right Flutter version by itself:

[project]
name = "gestion-queso"
version = "1.0.0"
requires-python = ">=3.10"
dependencies = ["flet"]

[tool.flet]
product = "Gestión de Queso"
org = "com.j053"

- uses: actions/setup-python@v5
  with:
    python-version: "3.12"
- run: pip install flet-cli flet
- run: flet build apk --yes --verbose

(Remove the subosito/flutter-action step.)

Flet 1.0 removed some APIs your main.py uses, so you'll need a few changes:

• ft.colors.X → ft.Colors.X, ft.icons.X → ft.Icons.X
• page.dialog = dlg; dlg.open = True; page.update() → page.show_dialog(dlg), and close with page.pop_dialog()
• page.snack_bar = ...; .open = True → page.show_dialog(ft.SnackBar(...))
• ft.ElevatedButton → ft.Button
• Dropdown.on_change → Dropdown.on_select, ft.dropdown.Option → ft.DropdownOption
• ft.app(target=main) → ft.run(main)

Run it once on desktop with flet run to catch anything else before building the APK.