fix: bring back a swiped-away ring notification

From Android 14 a foreground service's notification can be swiped away on
an unlocked phone, which left a sounding alarm with no controls. The ring
notification now reposts itself when it is deleted, and tapping a ringing
alarm in the list opens its ring screen.

app/src/main/java/de/jeanlucmakiola/clockula/alarm/AlarmIntents.kt

@@ -25,6 +25,7 @@ object AlarmIntents {
     const val REQUEST_SHOW: Int = 3
     const val REQUEST_SNOOZE: Int = 4
     const val REQUEST_DISMISS: Int = 5
+    const val REQUEST_REPOST: Int = 6
 
     val ALL_REQUEST_CODES: List<Int> = listOf(
         REQUEST_FIRE,
@@ -32,5 +33,6 @@ object AlarmIntents {
         REQUEST_SHOW,
         REQUEST_SNOOZE,
         REQUEST_DISMISS,
+        REQUEST_REPOST,
     )
 }

app/src/main/java/de/jeanlucmakiola/clockula/alarm/ring/AlarmRingService.kt

@@ -1,6 +1,8 @@
 package de.jeanlucmakiola.clockula.alarm.ring
 
 import android.app.Notification
+import android.app.NotificationManager
+import android.app.PendingIntent
 import android.app.Service
 import android.content.Context
 import android.content.Intent
@@ -51,6 +53,9 @@ class AlarmRingService : Service() {
     private var wakeLock: PowerManager.WakeLock? = null
     private var ringing: Job? = null
 
+    /** The notification last posted, put back as it was when the user swipes it away. */
+    private var posted: Notification? = null
+
     override fun onBind(intent: Intent?): IBinder? = null
 
     override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
@@ -58,6 +63,16 @@ class AlarmRingService : Service() {
             stop()
             return START_NOT_STICKY
         }
+        if (intent?.action == ACTION_REPOST) {
+            // The ring is untouched; only its notification comes back. A
+            // service the system recreated has nothing to repost yet, so it
+            // starts the ring as any other start would.
+            posted?.let {
+                getSystemService(NotificationManager::class.java)
+                    .notify(RingNotifications.RING_NOTIFICATION_ID, it)
+                return START_REDELIVER_INTENT
+            }
+        }
 
         // The whole ring is released, not just the coroutine: cancelling the job
         // alone would orphan a MediaPlayer the previous start had already
@@ -115,7 +130,7 @@ class AlarmRingService : Service() {
      * screen.
      */
     private fun startForegroundPreparing() {
-        startForeground(RingNotifications.preparing(this, presentation()))
+        startForeground(RingNotifications.preparing(this, presentation(), repostPendingIntent()))
     }
 
     private fun startForeground(session: RingSession) {
@@ -124,13 +139,22 @@ class AlarmRingService : Service() {
                 context = this,
                 session = session,
                 presentation = presentation(),
+                repost = repostPendingIntent(),
             ),
         )
     }
 
     private fun presentation() = RingPresentationPolicy.forCapabilities(capabilities.snapshot())
 
+    private fun repostPendingIntent(): PendingIntent = PendingIntent.getService(
+        this,
+        AlarmIntents.REQUEST_REPOST,
+        Intent(this, AlarmRingService::class.java).setAction(ACTION_REPOST),
+        PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE,
+    )
+
     private fun startForeground(notification: Notification) {
+        posted = notification
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
             // systemExempted: Android's own guidance names an app holding an
             // exact-alarm permission and continuing an alarm in the background.
@@ -164,12 +188,14 @@ class AlarmRingService : Service() {
 
     private fun stop() {
         releaseRing()
+        posted = null
         stopForeground(STOP_FOREGROUND_REMOVE)
         stopSelf()
     }
 
     companion object {
         private const val ACTION_STOP = AlarmIntents.ACTION_DISMISS + ".SERVICE_STOP"
+        private const val ACTION_REPOST = AlarmIntents.ACTION_DISMISS + ".SERVICE_REPOST"
         private const val WAKE_LOCK_TAG = "clockula:alarm-ring"
 
         /** A backstop on the backstop: the ring window is ten minutes. */

app/src/main/java/de/jeanlucmakiola/clockula/alarm/ring/RingNotifications.kt

@@ -82,7 +82,7 @@ object RingNotifications {
      * closes when there is none, so a dismiss that lands before the service's
      * read costs one brief screen wake, never a ring screen left up.
      */
-    fun preparing(context: Context, presentation: RingPresentation): Notification {
+    fun preparing(context: Context, presentation: RingPresentation, repost: PendingIntent): Notification {
         val show = showPendingIntent(context)
         val builder = NotificationCompat.Builder(context, RING_CHANNEL_ID)
             .setSmallIcon(R.drawable.ic_notification)
@@ -93,6 +93,7 @@ object RingNotifications {
             .setOngoing(true)
             .setAutoCancel(false)
             .setContentIntent(show)
+            .setDeleteIntent(repost)
         if (presentation.useFullScreenIntent) builder.setFullScreenIntent(show, true)
         return builder.build()
     }
@@ -104,11 +105,16 @@ object RingNotifications {
      * while snoozes are left, since a refused snooze dismisses; and an alarm
      * with a dismiss challenge has its Dismiss open the ring screen, where the
      * challenge is, rather than end the alarm from a heads-up or the lock screen.
+     *
+     * From Android 14 a foreground service's notification can be swiped away
+     * on an unlocked phone, ongoing or not. [repost] puts it back, so a
+     * sounding alarm never loses its controls.
      */
     fun ringing(
         context: Context,
         session: RingSession,
         presentation: RingPresentation,
+        repost: PendingIntent,
     ): Notification {
         val alarm = session.alarm
         val show = showPendingIntent(context)
@@ -122,6 +128,7 @@ object RingNotifications {
             .setOngoing(true)
             .setAutoCancel(false)
             .setContentIntent(show)
+            .setDeleteIntent(repost)
         if (session.canSnooze) {
             builder.addAction(
                 R.drawable.ic_notification,

app/src/main/java/de/jeanlucmakiola/clockula/ui/alarms/AlarmsScreen.kt

@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.clockula.ui.alarms
 
+import android.content.Intent
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.PaddingValues
@@ -19,11 +20,13 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.clockula.R
+import de.jeanlucmakiola.clockula.ui.ring.AlarmRingActivity
 import de.jeanlucmakiola.clockula.ui.shell.LocalLivePillInset
 import de.jeanlucmakiola.floret.components.CollapsingScaffold
 import de.jeanlucmakiola.floret.components.GroupedListInset
@@ -53,6 +56,7 @@ fun AlarmsScreen(
 ) {
     val state by viewModel.state.collectAsStateWithLifecycle()
     val rows = (state as? AlarmsUiState.Loaded)?.rows
+    val context = LocalContext.current
     val pillInset = LocalLivePillInset.current
     val addAlarm = stringResource(R.string.alarms_add)
 
@@ -99,7 +103,18 @@ fun AlarmsScreen(
             items(rows.orEmpty(), key = { row -> row.id }) { row ->
                 AlarmRow(
                     row = row,
-                    onClick = { onEditAlarm(row.id) },
+                    // A ringing alarm's row leads back to its ring screen, the
+                    // way out if its notification was swiped away.
+                    onClick = {
+                        if (row.ringing) {
+                            context.startActivity(
+                                Intent(context, AlarmRingActivity::class.java)
+                                    .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
+                            )
+                        } else {
+                            onEditAlarm(row.id)
+                        }
+                    },
                     onToggle = { enabled -> viewModel.onToggleEnabled(row.id, enabled) },
                     // An alarm whose time changed slides to its new place
                     // instead of teleporting.