feat(android): tell the page when the phone changes network

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2 files changed, 26 insertions, 0 deletions

diff --git a/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/MainActivity.kt b/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/MainActivity.kt
index 7ec81693..75ac0156 100644
--- a/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/MainActivity.kt
+++ b/packages/meshbay-android/app/src/main/kotlin/org/meshbay/client/MainActivity.kt
@@ -353,11 +353,25 @@ class MainActivity : Activity() {
      * Tells the page when the network becomes unmetered or stops being: a
      * backup waiting for Wi-Fi starts, one running on it stops. An event on the
      * window, carrying the one boolean and nothing about the network.
+     *
+     * And when the phone moves to another network altogether, mobile data to
+     * Wi-Fi or back: a connection to a node may be running over the one just
+     * left, and the page checks it (transport.js onNetworkChange). Nothing
+     * about either network goes with it.
      */
     private fun watchNetwork() {
         val cm = getSystemService(android.net.ConnectivityManager::class.java)
         var last: Boolean? = null
+        var current: android.net.Network? = null
         val callback = object : android.net.ConnectivityManager.NetworkCallback() {
+            override fun onAvailable(n: android.net.Network) {
+                val moved = current != null && current != n
+                current = n
+                if (moved) runOnUiThread {
+                    if (::web.isInitialized) web.evaluateJavascript(
+                        "window.dispatchEvent(new Event('meshbay-default-network'));", null)
+                }
+            }
             override fun onCapabilitiesChanged(n: android.net.Network, caps: android.net.NetworkCapabilities) = tell()
             override fun onLost(n: android.net.Network) = tell()
             private fun tell() {
diff --git a/packages/meshbay-hub/tests/test_android_shell.py b/packages/meshbay-hub/tests/test_android_shell.py
index cba4b320..eedc1988 100644
--- a/packages/meshbay-hub/tests/test_android_shell.py
+++ b/packages/meshbay-hub/tests/test_android_shell.py
@@ -263,6 +263,18 @@ def test_the_local_network_is_asked_for_when_a_group_opens():
     assert "lanAsked = true" in asked[1][:200]
 
 
+def test_the_page_hears_when_the_phone_changes_network():
+    """A connection to the node may run over the network the phone just left,
+    and the page checks it then (transport.js onNetworkChange). Said by an
+    event that carries nothing about either network."""
+    activity = _read(SRC / "MainActivity.kt")
+    watch = activity.split("private fun watchNetwork()", 1)[1].split("\n    override fun ", 1)[0]
+    assert "override fun onAvailable" in watch
+    assert "new Event('meshbay-default-network')" in watch
+    from spa_source import transport_source
+    assert "'meshbay-default-network'" in transport_source()
+
+
 def test_no_backup_carries_the_keys_away():
     manifest = _read(APP / "src" / "main" / "AndroidManifest.xml")
     assert 'android:allowBackup="false"' in manifest