Avoid haptics while app in background

Author: sameerasw

app/src/main/java/com/sameerasw/airsync/presentation/ui/screens/AirSyncMainScreen.kt

@@ -39,6 +39,7 @@ import androidx.compose.material.icons.filled.QrCodeScanner
 import androidx.compose.material.icons.filled.LinkOff
 import androidx.compose.material.icons.outlined.Phonelink
 import androidx.compose.material.icons.outlined.Settings
+import androidx.lifecycle.compose.LocalLifecycleOwner
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.sameerasw.airsync.presentation.viewmodel.AirSyncViewModel
 import com.sameerasw.airsync.utils.ClipboardSyncManager
@@ -95,6 +96,7 @@ fun AirSyncMainScreen(
     val deviceInfo by viewModel.deviceInfo.collectAsState()
     val scope = rememberCoroutineScope()
     val haptics = LocalHapticFeedback.current
+    val lifecycle = LocalLifecycleOwner.current.lifecycle
     val connectScrollState = rememberScrollState()
     val settingsScrollState = rememberScrollState()
     var hasProcessedQrDialog by remember { mutableStateOf(false) }
@@ -306,8 +308,7 @@ fun AirSyncMainScreen(
     // Start/stop loading haptics when connecting
     LaunchedEffect(uiState.isConnecting) {
         if (uiState.isConnecting) {
-            loadingHapticsJob?.cancel()
-            loadingHapticsJob = HapticUtil.startLoadingHaptics(haptics)
+            loadingHapticsJob = HapticUtil.startLoadingHaptics(haptics, lifecycle)
         } else {
             loadingHapticsJob?.cancel()
             loadingHapticsJob = null

app/src/main/java/com/sameerasw/airsync/utils/HapticUtil.kt

@@ -8,6 +8,7 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.isActive
+import androidx.lifecycle.Lifecycle
 
 object HapticUtil {
     /**
@@ -49,12 +50,27 @@ object HapticUtil {
     /**
      * Start repeating haptic ticks for loading states
      * Returns a Job that can be cancelled to stop the haptics
+     *
+     * If a lifecycle is provided, haptics will only fire while the lifecycle
+     * is at least STARTED (i.e. the app/screen is in foreground). This prevents
+     * haptics from triggering while the app is backgrounded.
      */
-    fun startLoadingHaptics(haptics: HapticFeedback?): Job {
+    fun startLoadingHaptics(haptics: HapticFeedback?, lifecycle: Lifecycle? = null): Job {
         return CoroutineScope(Dispatchers.Main).launch {
             while (isActive) {
-                performLightTick(haptics)
-                delay(200) // 5 times per second
+                try {
+                    val shouldRun = lifecycle?.currentState?.isAtLeast(Lifecycle.State.STARTED) ?: true
+                    if (shouldRun) {
+                        performLightTick(haptics)
+                        delay(200) // 5 times per second
+                    } else {
+                        // Backoff while app is backgrounded; poll until it becomes STARTED again
+                        delay(200)
+                    }
+                } catch (_: Exception) {
+                    // swallow any exceptions from lifecycle or haptics and continue
+                    delay(200)
+                }
             }
         }
     }