Initial commit: EventTracker desktop app + Android companion

Desktop: GTK3 + matplotlib app tracking arbitrary events (button ->
timestamp -> CSV), with per-event stats, trend charts, settings
(rename/add events, relocate data file), and a reset-with-backup flow.
Portable desktop launcher via a .desktop.in template + install script,
no machine-specific paths baked in.

Android: minimal Kivy v1 companion reading/writing the same CSV format,
plus buildozer build tooling isolated in a venv and a local p4a recipe
override for kivy (see CLAUDE.md for why).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

android/p4a-recipes/kivy/__init__.py

@@ -0,0 +1,110 @@
+# Local override of p4a's built-in kivy recipe — identical except
+# python_depends is emptied. See buildozer.spec for why: upstream's
+# ['certifi', 'chardet', 'idna', 'requests', 'urllib3', 'filetype'] pulls
+# in requests -> charset-normalizer, whose newest release ships an
+# Android-tagged wheel that p4a's own install step can't actually install
+# (see comment in buildozer.spec). We never call kivy.network.UrlRequest,
+# so dropping the whole chain is correct, not just a workaround.
+from os.path import join
+import sys
+import packaging.version
+
+import sh
+from pythonforandroid.recipe import PyProjectRecipe
+from pythonforandroid.toolchain import current_directory, shprint
+
+
+def get_kivy_version(recipe, arch):
+    with current_directory(join(recipe.get_build_dir(arch.arch), "kivy")):
+        return shprint(
+            sh.Command(sys.executable),
+            "-c",
+            "import _version; print(_version.__version__)",
+        )
+
+
+def is_kivy_affected_by_deadlock_issue(recipe=None, arch=None):
+    return packaging.version.parse(
+        str(get_kivy_version(recipe, arch))
+    ) < packaging.version.Version("2.2.0.dev0")
+
+
+def is_kivy_less_than_3(recipe=None, arch=None):
+    return packaging.version.parse(
+        str(get_kivy_version(recipe, arch))
+    ) < packaging.version.Version("3.0.0.dev0")
+
+
+class KivyRecipe(PyProjectRecipe):
+    version = '2.3.1'
+    url = 'https://github.com/kivy/kivy/archive/{version}.zip'
+    name = 'kivy'
+
+    depends = [('sdl2', 'sdl3'), 'pyjnius', 'setuptools', 'android']
+    python_depends = []  # upstream: ['certifi', 'chardet', 'idna', 'requests', 'urllib3', 'filetype'] — unused, see buildozer.spec
+    hostpython_prerequisites = ["cython>=0.29.1,<=3.0.12"]
+
+    # sdl-gl-swapwindow-nogil.patch is needed to avoid a deadlock.
+    # See: https://github.com/kivy/kivy/pull/8025
+    # WARNING: Remove this patch when a new Kivy version is released.
+    patches = [
+        ("sdl-gl-swapwindow-nogil.patch", is_kivy_affected_by_deadlock_issue),
+        ("use_cython.patch", is_kivy_less_than_3),
+        "no-ast-str.patch"
+    ]
+
+    @property
+    def need_stl_shared(self):
+        if "sdl3" in self.ctx.recipe_build_order:
+            return True
+        else:
+            return False
+
+    def get_recipe_env(self, arch, **kwargs):
+        env = super().get_recipe_env(arch, **kwargs)
+
+        # Taken from CythonRecipe
+        env['LDFLAGS'] = env['LDFLAGS'] + ' -L{} '.format(
+            self.ctx.get_libs_dir(arch.arch) +
+            ' -L{} '.format(self.ctx.libs_dir) +
+            ' -L{}'.format(join(self.ctx.bootstrap.build_dir, 'obj', 'local',
+                                arch.arch)))
+        env['LDSHARED'] = env['CC'] + ' -shared'
+        env['LIBLINK'] = 'NOTNONE'
+
+        # NDKPLATFORM is our switch for detecting Android platform, so can't be None
+        env['NDKPLATFORM'] = "NOTNONE"
+        if not is_kivy_less_than_3(self, arch):
+            env['KIVY_CROSS_PLATFORM'] = 'android'
+
+        if 'sdl2' in self.ctx.recipe_build_order:
+            env['USE_SDL2'] = '1'
+            env['KIVY_SPLIT_EXAMPLES'] = '1'
+            sdl2_mixer_recipe = self.get_recipe('sdl2_mixer', self.ctx)
+            sdl2_image_recipe = self.get_recipe('sdl2_image', self.ctx)
+            env['KIVY_SDL2_PATH'] = ':'.join([
+                join(self.ctx.bootstrap.build_dir, 'jni', 'SDL', 'include'),
+                *sdl2_image_recipe.get_include_dirs(arch),
+                *sdl2_mixer_recipe.get_include_dirs(arch),
+                join(self.ctx.bootstrap.build_dir, 'jni', 'SDL2_ttf'),
+            ])
+        if "sdl3" in self.ctx.recipe_build_order:
+            sdl3_mixer_recipe = self.get_recipe("sdl3_mixer", self.ctx)
+            sdl3_image_recipe = self.get_recipe("sdl3_image", self.ctx)
+            sdl3_ttf_recipe = self.get_recipe("sdl3_ttf", self.ctx)
+            sdl3_recipe = self.get_recipe("sdl3", self.ctx)
+            env["USE_SDL3"] = "1"
+            env["KIVY_SPLIT_EXAMPLES"] = "1"
+            env["KIVY_SDL3_PATH"] = ":".join(
+                [
+                    *sdl3_mixer_recipe.get_include_dirs(arch),
+                    *sdl3_image_recipe.get_include_dirs(arch),
+                    *sdl3_ttf_recipe.get_include_dirs(arch),
+                    *sdl3_recipe.get_include_dirs(arch),
+                ]
+            )
+
+        return env
+
+
+recipe = KivyRecipe()

android/p4a-recipes/kivy/no-ast-str.patch

@@ -0,0 +1,16 @@
+diff -ur kivy-2.3.1b/kivy/lang/parser.py kivy-2.3.1/kivy/lang/parser.py
+--- kivy-2.3.1b/kivy/lang/parser.py	2025-10-19 13:04:51.542798827 +1300
++++ kivy-2.3.1/kivy/lang/parser.py	2025-10-19 13:05:16.007104601 +1300
+@@ -230,11 +230,7 @@
+ 
+         if isinstance(node, (ast.JoinedStr, ast.BoolOp)):
+             for n in node.values:
+-                if isinstance(n, ast.Str):
+-                    # NOTE: required for python3.6
+-                    yield from cls.get_names_from_expression(n.s)
+-                else:
+-                    yield from cls.get_names_from_expression(n.value)
++                yield from cls.get_names_from_expression(n.value)
+ 
+         if isinstance(node, ast.BinOp):
+             yield from cls.get_names_from_expression(node.right)

android/p4a-recipes/kivy/sdl-gl-swapwindow-nogil.patch

@@ -0,0 +1,32 @@
+diff --git a/kivy/core/window/_window_sdl2.pyx b/kivy/core/window/_window_sdl2.pyx
+index 46e15ec63..5002cd0f9 100644
+--- a/kivy/core/window/_window_sdl2.pyx
++++ b/kivy/core/window/_window_sdl2.pyx
+@@ -746,7 +746,13 @@ cdef class _WindowSDL2Storage:
+             pass
+ 
+     def flip(self):
+-        SDL_GL_SwapWindow(self.win)
++        # On Android (and potentially other platforms), SDL_GL_SwapWindow may
++        # lock the thread waiting for a mutex from another thread to be
++        # released. Calling SDL_GL_SwapWindow with the GIL released allow the
++        # other thread to run (e.g. to process the event filter callback) and
++        # release the mutex SDL_GL_SwapWindow is waiting for.
++        with nogil:
++            SDL_GL_SwapWindow(self.win)
+ 
+     def save_bytes_in_png(self, filename, data, int width, int height):
+         cdef SDL_Surface *surface = SDL_CreateRGBSurfaceFrom(
+diff --git a/kivy/lib/sdl2.pxi b/kivy/lib/sdl2.pxi
+index 6a539de6d..3a5a69d23 100644
+--- a/kivy/lib/sdl2.pxi
++++ b/kivy/lib/sdl2.pxi
+@@ -627,7 +627,7 @@ cdef extern from "SDL.h":
+     cdef SDL_GLContext SDL_GL_GetCurrentContext()
+     cdef int SDL_GL_SetSwapInterval(int interval)
+     cdef int SDL_GL_GetSwapInterval()
+-    cdef void SDL_GL_SwapWindow(SDL_Window * window)
++    cdef void SDL_GL_SwapWindow(SDL_Window * window) nogil
+     cdef void SDL_GL_DeleteContext(SDL_GLContext context)
+ 
+     cdef int SDL_NumJoysticks()

android/p4a-recipes/kivy/use_cython.patch

@@ -0,0 +1,11 @@
+--- kivy-master/setup.py	2025-02-25 03:08:18.000000000 +0530
++++ kivy-master.mod/setup.py	2025-03-01 13:10:24.227808612 +0530
+@@ -249,7 +249,7 @@
+ # This determines whether Cython specific functionality may be used.
+ can_use_cython = True
+ 
+-if platform in ('ios', 'android'):
++if platform in ('ios'):
+     # NEVER use or declare cython on these platforms
+     print('Not using cython on %s' % platform)
+     can_use_cython = False