Pause the cellular signal chart from updating when the fragment is in…

… the background

networksurvey/src/main/java/com/craxiom/networksurvey/fragments/NetworkDetailsFragment.java

@@ -128,6 +128,14 @@ public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup c
         return binding.getRoot();
     }
 
+    @Override
+    public void onPause()
+    {
+        chartViewModel.pauseChartUpdates();
+
+        super.onPause();
+    }
+
     @Override
     public void onResume()
     {
@@ -139,6 +147,8 @@ public void onResume()
         initializeLocationTextView();
 
         startAndBindToService();
+
+        chartViewModel.resumeChartUpdates();
     }
 
     @Override

networksurvey/src/main/java/com/craxiom/networksurvey/ui/ASignalChartViewModel.kt

@@ -16,6 +16,7 @@ import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
 import timber.log.Timber
+import kotlin.concurrent.Volatile
 import kotlin.properties.ReadWriteProperty
 import kotlin.reflect.KProperty
 
@@ -60,6 +61,9 @@ abstract class ASignalChartViewModel : ViewModel() {
     private val xValueQueue: ArrayDeque<Int> by dequeLimiter(CHART_WIDTH)
     private val rssiQueue: ArrayDeque<Float> by dequeLimiter(CHART_WIDTH)
 
+    @Volatile
+    private var isPaused = false
+
     private val _latestChartRssi = MutableStateFlow(UNKNOWN_RSSI)
     private val latestChartRssi: StateFlow<Float> = _latestChartRssi.asStateFlow()
 
@@ -72,7 +76,7 @@ abstract class ASignalChartViewModel : ViewModel() {
             while (currentCoroutineContext().isActive) {
                 // This coroutine will make sure that the chart is updated every n seconds, even
                 // if there are not any new values coming in.
-                if (!rssiQueue.isEmpty()) {
+                if (!isPaused && !rssiQueue.isEmpty()) {
                     addRssiToChart(latestChartRssi.value)
                 }
 
@@ -81,6 +85,21 @@ abstract class ASignalChartViewModel : ViewModel() {
         }
     }
 
+    /**
+     * Pauses updates to the chart so that the chart does not keep getting values added when the
+     * fragment is in the background.
+     */
+    fun pauseChartUpdates() {
+        isPaused = true;
+    }
+
+    /**
+     * Resumes updates to the chart.
+     */
+    fun resumeChartUpdates() {
+        isPaused = false;
+    }
+
     /**
      * The label to use for the marker text on the chart. If this is an empty string, then the
      * default marker text is displayed (the y-axis value). Override this method to provide a