commit eff6100eb59979db4c0544efa9a8e3344d1eb7f0
Author: Fabio Mazza <fab4mazz@gmail.com>
Date:   Wed Apr 23 12:06:41 2025 +0200

    Restore map state on re-drawing of the map

diff --git a/app/src/main/java/it/reyboz/bustorino/fragments/MapLibreFragment.kt b/app/src/main/java/it/reyboz/bustorino/fragments/MapLibreFragment.kt
index 8d30067..5c29d21 100644
--- a/app/src/main/java/it/reyboz/bustorino/fragments/MapLibreFragment.kt
+++ b/app/src/main/java/it/reyboz/bustorino/fragments/MapLibreFragment.kt
@@ -124,7 +124,7 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
     private lateinit var centerUserButton: ImageButton
     private lateinit var followUserButton: ImageButton
     private var followingUserLocation = false
-    private var shouldShowLocation = false
+    private var pendingLocationActivation = false
     private var ignoreCameraMovementForFollowing = true
     private var enablingPositionFromClick = false
     private val positionRequestLauncher =
@@ -181,6 +181,11 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
     private var initialStopToShow : Stop? = null
     private var initialStopShown = false
 
+    //shown stuff
+    private var savedStateOnStop : Bundle? = null
+    private var savedMapStateOnPause : Bundle? = null
+    private var shownStopInBottomSheet : Stop? = null
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         arguments?.let {
@@ -204,9 +209,13 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
 
         // Init the MapView
         mapView = rootView.findViewById(R.id.libreMapView)
+        if(savedStateOnStop!=null){
+            mapView.onCreate(savedStateOnStop)
+        } else mapView.onCreate(savedInstanceState)
         mapView.getMapAsync(this) //{ //map ->
             //map.setStyle("https://demotiles.maplibre.org/style.json") }
 
+
         //init bottom sheet
         val bottomSheet = rootView.findViewById<RelativeLayout>(R.id.bottom_sheet)
         bottomLayout = bottomSheet
@@ -277,12 +286,10 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
      */
     override fun onMapReady(mapReady: MapLibreMap) {
         this.map = mapReady
-        //TODO: Check if we have the user last position and start the map there
 
         val mjson = Styles.getJsonStyleFromAsset(requireContext(), "map_style_good_noshops.json")
         //ViewUtils.loadJsonFromAsset(requireContext(),"map_style_good.json")
 
-
         activity?.run {
             val builder = Style.Builder().fromJson(mjson!!)
 
@@ -310,6 +317,14 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
                 //init stop layer with this
                 displayStops(stopsViewModel.getAllStopsLoaded())
                 setupBusLayer(style)
+
+                savedMapStateOnPause?.let{
+                    restoreMapStateFromBundle(it)
+                    pendingLocationActivation = false
+                    Log.d(DEBUG_TAG, "Restored map state from the saved bundle")
+                }
+                //reset saved State at the end
+
             }
 
             mapReady.addOnCameraIdleListener {
@@ -377,13 +392,17 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
             // we start requesting the bus positions now
             startRequestingPositions()
         }
-
-        val zoom = 15.0
-        //center position
-        val latlngTarget = initialStopToShow?.let {
-            LatLng(it.latitude!!, it.longitude!!) } ?: LatLng(DEFAULT_CENTER_LAT, DEFAULT_CENTER_LON)
-        mapReady.cameraPosition = CameraPosition.Builder().target(latlngTarget).zoom(zoom).build()
-
+        if( savedMapStateOnPause == null) {
+            //set initial state
+            val zoom = 15.0
+            //center position
+            val latlngTarget = initialStopToShow?.let {
+                LatLng(it.latitude!!, it.longitude!!)
+            } ?: LatLng(DEFAULT_CENTER_LAT, DEFAULT_CENTER_LON)
+            mapReady.cameraPosition = CameraPosition.Builder().target(latlngTarget).zoom(zoom).build()
+        }
+        //reset saved state
+        savedMapStateOnPause = null
     }
 
 
@@ -429,16 +448,6 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
                 PropertyFactory.iconRotate(Expression.get("bearing")),
                 PropertyFactory.iconRotationAlignment(ICON_ROTATION_ALIGNMENT_MAP)
 
-                /*PropertyFactory.textField("label"),
-                PropertyFactory.textSize(12f),
-                PropertyFactory.textColor(Color.BLACK),
-                //PropertyFactory.textHaloColor(Color.BLACK),
-                //PropertyFactory.textHaloWidth(1f),
-                PropertyFactory.textAnchor(TEXT_ANCHOR_CENTER),
-                PropertyFactory.textAllowOverlap(true),
-                PropertyFactory.textRotationAlignment(TEXT_ROTATION_ALIGNMENT_VIEWPORT)
-
-                 */
             )
         }
         style.addLayerAbove(busesLayer, STOPS_LAYER_ID)
@@ -488,20 +497,6 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
         }
         //add stop marker
         if (stop.latitude!=null && stop.longitude!=null) {
-            /*val marker = map?.addMarker(
-                MarkerOptions()
-                    .position(LatLng(stop.latitude!!, stop.longitude!!)) // example coords
-                    .icon(
-                        //IconFactory.getInstance(requireContext()).fromBitmap(
-                        getIconFromVectorDrawable(requireContext(), R.drawable.bus_stop_new_highlight)
-                                    //R.drawable.bus_stop_new_highlight)
-                                //IconFactory.getInstance(requireContext())
-                            //.fromResource(R.drawable.bus_stop_new_highlight)
-                    )
-                    .title(stop.stopDefaultName)
-
-            )
-             */
             stopActiveSymbol = symbolManager.create(
                 SymbolOptions()
                     .withLatLng(LatLng(stop.latitude!!, stop.longitude!!))
@@ -511,6 +506,7 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
             )
 
         }
+        shownStopInBottomSheet = stop
         bottomSheetBehavior.state = BottomSheetBehavior.STATE_EXPANDED
 
     }
@@ -564,12 +560,18 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
         super.onPause()
         mapView.onPause()
         Log.d(DEBUG_TAG, "Fragment paused")
+
+        savedMapStateOnPause = saveMapStateInBundle()
     }
 
     override fun onStop() {
         super.onStop()
         mapView.onStop()
         Log.d(DEBUG_TAG, "Fragment stopped!")
+        savedStateOnStop = Bundle().let {
+            mapView.onSaveInstanceState(it)
+            it
+        }
 
     }
 
@@ -591,6 +593,7 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
     override fun onSaveInstanceState(outState: Bundle) {
         super.onSaveInstanceState(outState)
         mapView.onSaveInstanceState(outState)
+        Log.d(DEBUG_TAG, "Saved instanceState")
     }
 
     private fun observeViewModels() {
@@ -664,6 +667,8 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
         if(initialStopToShow!=null){
             initialStopToShow = null
         }
+
+        shownStopInBottomSheet = null
     }
     // --------------- BUS LOCATIONS STUFF --------------------------
     /**
@@ -893,37 +898,35 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
 
     @SuppressLint("MissingPermission")
     private fun requestInitialUserLocation() {
-        val provider :String? = LocationManager.GPS_PROVIDER//getBestLocationProvider()
-
-        provider?.let {
-            setLocationIconEnabled(true)
-            Toast.makeText(requireContext(), R.string.position_searching_message, Toast.LENGTH_SHORT).show()
-            shouldShowLocation = true
-            locationManager.requestSingleUpdate(it, object : LocationListener {
-                override fun onLocationChanged(location: Location) {
-                    val userLatLng = LatLng(location.latitude, location.longitude)
-                    val distanceToTarget = userLatLng.distanceTo(DEFAULT_LATLNG)
-
-                    if (distanceToTarget <= MAX_DIST_KM*1000.0) {
-                        map?.let{
-                            // if we are still waiting for the position to enable
-                            if(shouldShowLocation)
-                                setMapLocationEnabled(true, true, false)
-                        }
-                    } else {
-                        Toast.makeText(context, "You are too far, not showing the position", Toast.LENGTH_SHORT).show()
+        val provider : String = LocationManager.GPS_PROVIDER//getBestLocationProvider()
+
+        //provider.let {
+        setLocationIconEnabled(true)
+        Toast.makeText(requireContext(), R.string.position_searching_message, Toast.LENGTH_SHORT).show()
+        pendingLocationActivation = true
+        locationManager.requestSingleUpdate(provider, object : LocationListener {
+            override fun onLocationChanged(location: Location) {
+                val userLatLng = LatLng(location.latitude, location.longitude)
+                val distanceToTarget = userLatLng.distanceTo(DEFAULT_LATLNG)
+
+                if (distanceToTarget <= MAX_DIST_KM*1000.0) {
+                    map?.let{
+                        // if we are still waiting for the position to enable
+                        if(pendingLocationActivation)
+                            setMapLocationEnabled(true, true, false)
                     }
+                } else {
+                    Toast.makeText(context, "You are too far, not showing the position", Toast.LENGTH_SHORT).show()
                 }
+            }
 
-                override fun onProviderDisabled(provider: String) {}
-                override fun onProviderEnabled(provider: String) {}
+            override fun onProviderDisabled(provider: String) {}
+            override fun onProviderEnabled(provider: String) {}
+
+            @Deprecated("Deprecated in Java")
+            override fun onStatusChanged(provider: String?, status: Int, extras: Bundle?) {}
+        }, null)
 
-                @Deprecated("Deprecated in Java")
-                override fun onStatusChanged(provider: String?, status: Int, extras: Bundle?) {}
-            }, null)
-        } ?: run {
-            Toast.makeText(context, "No suitable location provider found.", Toast.LENGTH_SHORT).show()
-        }
     }
 
     /**
@@ -1003,7 +1006,7 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
             setLocationIconEnabled(false)
             if (fromClick) {
                 Toast.makeText(requireContext(), R.string.location_disabled, Toast.LENGTH_SHORT).show()
-                if(shouldShowLocation) shouldShowLocation=false //Cancel the request for the enablement of the position
+                if(pendingLocationActivation) pendingLocationActivation=false //Cancel the request for the enablement of the position
             }
         }
 
@@ -1036,13 +1039,46 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
 
 
     private fun switchUserLocationStatus(view: View?){
-        if(shouldShowLocation || locationComponent.isLocationComponentEnabled) setMapLocationEnabled(false, false, true)
+        if(pendingLocationActivation || locationComponent.isLocationComponentEnabled) setMapLocationEnabled(false, false, true)
         else{
             Log.d(DEBUG_TAG, "Request enable location")
             setMapLocationEnabled(true, false, true)
         }
     }
 
+    private fun saveMapStateBeforePause(bundle: Bundle){
+        map?.let {
+            val newBbox = it.projection.visibleRegion.latLngBounds
+
+            bundle.putDouble("center_map_lat", newBbox.center.latitude)
+            bundle.putDouble("center_map_lon", newBbox.center.longitude)
+            it.cameraPosition.zoom.let { z-> bundle.putDouble("map_zoom",z) }
+        }
+        shownStopInBottomSheet?.let {
+            bundle.putBundle("shown_stop", it.toBundle())
+        }
+    }
+    private fun saveMapStateInBundle(): Bundle {
+        val b = Bundle()
+        saveMapStateBeforePause(b)
+        return b
+    }
+
+    private fun restoreMapStateFromBundle(bundle: Bundle){
+        val latCenter = bundle.getDouble("center_map_lat", -10.0)
+        val lonCenter = bundle.getDouble("center_map_lon",-10.0)
+        val zoom = bundle.getDouble("map_zoom", -10.0)
+        if(lonCenter>=0 &&latCenter>=0) map?.let {
+            val newPos = CameraPosition.Builder().target(LatLng(latCenter,lonCenter))
+            if(zoom>0) newPos.zoom(zoom)
+            it.cameraPosition=newPos.build()
+        }
+        val mStop = bundle.getBundle("shown_stop")?.let {
+            Stop.fromBundle(it)
+        }
+        mStop?.let { openStopInBottomSheet(it) }
+    }
+
     companion object {
         private const val STOPS_SOURCE_ID = "stops-source"
         private const val STOPS_LAYER_ID = "stops-layer"
@@ -1058,8 +1094,8 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
         private const val POSITION_FOUND_ZOOM = 16.5
         private const val NO_POSITION_ZOOM = 17.1
         private const val MAX_DIST_KM = 90.0
-        private const val ACCESS_TOKEN="KxO8lF4U3kiO63m0c7lzqDCDrMUVg1OA2JVzRXxxmYSyjugr1xpe4W4Db5rFNvbQ"
-        private const val MAPLIBRE_URL = "https://api.jawg.io/styles/"
+        //private const val ACCESS_TOKEN="KxO8lF4U3kiO63m0c7lzqDCDrMUVg1OA2JVzRXxxmYSyjugr1xpe4W4Db5rFNvbQ"
+        //private const val MAPLIBRE_URL = "https://api.jawg.io/styles/"
         private const val DEBUG_TAG = "BusTO-MapLibreFrag"
         private const val STOP_ACTIVE_IMG = "Stop-active"
 
@@ -1069,21 +1105,20 @@ class MapLibreFragment : ScreenBaseFragment(), OnMapReadyCallback {
          * Use this factory method to create a new instance of
          * this fragment using the provided parameters.
          *
-         * @param param1 Parameter 1.
-         * @param param2 Parameter 2.
+         * @param stop Eventual stop to center the map into
          * @return A new instance of fragment MapLibreFragment.
          */
-        // TODO: Use parcelable interface?
         @JvmStatic
         fun newInstance(stop: Stop?) =
             MapLibreFragment().apply {
                 arguments = Bundle().let {
+                    // Cannot use Parcelable as it requires higher version of Android
                     //stop?.let{putParcelable(STOP_TO_SHOW, it)}
                     stop?.toBundle(it)
                 }
             }
-        private fun makeStyleUrl(style: String = "jawg-streets") =
-            "${MAPLIBRE_URL+ style}.json?access-token=${ACCESS_TOKEN}"
+        //private fun makeStyleUrl(style: String = "jawg-streets") =
+         //   "${MAPLIBRE_URL+ style}.json?access-token=${ACCESS_TOKEN}"
         private fun makeStyleMapBoxUrl(dark: Boolean) =
              if(dark)
                 "https://basemaps.cartocdn.com/gl/dark-matter-gl-style/style.json"