3 files changed, 26 insertions, 2 deletions
diff --git a/android/app/src/main/AndroidManifest.xml b/android/app/src/main/AndroidManifest.xml
index 0444b76..2f0f950 100644
--- a/android/app/src/main/AndroidManifest.xml
+++ b/android/app/src/main/AndroidManifest.xml
@@ -14,6 +14,9 @@
     <intent>
       <action android:name="org.unifiedpush.android.distributor.REGISTER" />
     </intent>
+    <!-- whether Google Play Services is here (Push.playServices): with it, the
+         TWA's web push works and UnifiedPush isn't asked -->
+    <package android:name="com.google.android.gms" />
   </queries>
   <application
       android:label="@string/app_name"
diff --git a/android/app/src/main/java/io/coinos/app/Push.java b/android/app/src/main/java/io/coinos/app/Push.java
index 925693a..932fc11 100644
--- a/android/app/src/main/java/io/coinos/app/Push.java
+++ b/android/app/src/main/java/io/coinos/app/Push.java
@@ -120,6 +120,19 @@ public final class Push {
     p.edit().putInt(KEY_TRY, p.getInt(KEY_TRY, 0) + 1).putLong(KEY_TRY_AT, 0).remove(KEY_DIST).apply();
   }
 
+  /**
+   * Google Play Services, installed and switched on — what web push on
+   * Android runs through. (Its package is named in the manifest's queries:
+   * Android 11+ hides it otherwise.)
+   */
+  static boolean playServices(Context c) {
+    try {
+      return c.getPackageManager().getApplicationInfo("com.google.android.gms", 0).enabled;
+    } catch (Exception e) {
+      return false;
+    }
+  }
+
   static String endpoint(Context c) {
     return prefs(c).getString(KEY_ENDPOINT, null);
   }
diff --git a/android/app/src/twa/java/io/coinos/app/LauncherActivity.java b/android/app/src/twa/java/io/coinos/app/LauncherActivity.java
index bf960e2..6e05403 100644
--- a/android/app/src/twa/java/io/coinos/app/LauncherActivity.java
+++ b/android/app/src/twa/java/io/coinos/app/LauncherActivity.java
@@ -27,12 +27,20 @@ public class LauncherActivity
   @Override
   protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
+    // UnifiedPush is for phones without Google Play Services (GrapheneOS and
+    // the like, without the sandboxed Play): web push reaches Chrome — and so
+    // this app — through Google, and with it there it already does. Asking
+    // ntfy as well there only put up its prompt in an app the user hadn't
+    // asked for anything (and would have brought every notification twice).
+    // A registration already made is kept: whoever has one has been through
+    // the prompt, and may be counting on it.
+    boolean unifiedPush = !Push.playServices(this) || Push.endpoint(this) != null;
     // Ask the distributor on every launch: it's idempotent, and it's how a
     // distributor installed after us ever gets noticed.
-    Push.register(this);
+    if (unifiedPush) Push.register(this);
     // Android 13+ won't show our notifications without this, and the TWA's
     // own permission covers the browser's, not ours.
-    if (Build.VERSION.SDK_INT >= 33
+    if (unifiedPush && Build.VERSION.SDK_INT >= 33
         && checkSelfPermission(Manifest.permission.POST_NOTIFICATIONS) != PackageManager.PERMISSION_GRANTED
         && Push.distributor(this) != null) {
       try { requestPermissions(new String[] { Manifest.permission.POST_NOTIFICATIONS }, 1); } catch (Exception ignored) {}