android: add support for adaptive icon/launcher (#2446)

see https://developer.android.com/guide/practices/ui_guidelines/icon_design_adaptive

This adds a `--icon-fg` and a `--icon-bg` build option to the sdl2 bootstrap,
that can be used to specify two PNG files to be used as the foreground and background
of an adaptive icon. These will get used if API 26+ is available at runtime.
The existing `--icon` option to specify an icon as a single PNG file is kept, as
- this provides backwards compatibility,
- and even if the new options are used, it might be a good idea to set all three
  options: when running on API <26, the PNG specified via `--icon` gets used.

Author: SomberNight

pythonforandroid/bootstraps/common/build/build.py

@@ -342,8 +342,21 @@ def make_package(args):
     default_presplash = 'templates/kivy-presplash.jpg'
     shutil.copy(
         args.icon or default_icon,
-        join(res_dir, 'drawable/icon.png')
+        join(res_dir, 'mipmap/icon.png')
     )
+    if args.icon_fg and args.icon_bg:
+        shutil.copy(args.icon_fg, join(res_dir, 'mipmap/icon_foreground.png'))
+        shutil.copy(args.icon_bg, join(res_dir, 'mipmap/icon_background.png'))
+        with open(join(res_dir, 'mipmap-anydpi-v26/icon.xml'), "w") as fd:
+            fd.write("""<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@mipmap/icon_background"/>
+    <foreground android:drawable="@mipmap/icon_foreground"/>
+</adaptive-icon>
+""")
+    elif args.icon_fg or args.icon_bg:
+        print("WARNING: Received an --icon_fg or an --icon_bg argument, but not both. "
+              "Ignoring.")
 
     if args.enable_androidx:
         shutil.copy('templates/gradle.properties', 'gradle.properties')
@@ -673,6 +686,12 @@ def parse_args_and_make_package(args=None):
     ap.add_argument('--icon', dest='icon',
                     help=('A png file to use as the icon for '
                           'the application.'))
+    ap.add_argument('--icon-fg', dest='icon_fg',
+                    help=('A png file to use as the foreground of the adaptive icon '
+                          'for the application.'))
+    ap.add_argument('--icon-bg', dest='icon_bg',
+                    help=('A png file to use as the background of the adaptive icon '
+                          'for the application.'))
     ap.add_argument('--service', dest='services', action='append', default=[],
                     help='Declare a new service entrypoint: '
                          'NAME:PATH_TO_PY[:foreground]')

pythonforandroid/bootstraps/sdl2/build/src/main/res/mipmap-anydpi-v26/.gitkeep

@@ -56,7 +56,7 @@
     -->
     <application android:label="@string/app_name"
                  {% if debug %}android:debuggable="true"{% endif %}
-                 android:icon="@drawable/icon"
+                 android:icon="@mipmap/icon"
                  android:allowBackup="{{ args.allow_backup }}"
                  {% if args.backup_rules %}android:fullBackupContent="@xml/{{ args.backup_rules }}"{% endif %}
                  {{ args.extra_manifest_application_arguments }}
@@ -100,7 +100,7 @@
 
         {% if args.launcher %}
         <activity android:name="org.kivy.android.launcher.ProjectChooser"
-                  android:icon="@drawable/icon"
+                  android:icon="@mipmap/icon"
                   android:label="@string/app_name">
 
           <intent-filter>