From f77bd76af353bc0b62b59f5991414ba26e7cac2e Mon Sep 17 00:00:00 2001
From: simonpoole <simon@poole.ch>
Date: Sat, 9 Nov 2024 12:45:56 +0100
Subject: [PATCH] Don't force recreating the map object and associated layer
 state

If Main has been destroyed, both the Map and Logic objects may still be
available and current, so we now reuse them instead of forcing
recreation.

This resolves race conditions that could be caused by selecting and
loading files into layers via the system file picker that could lead to
Main being removed.
---
 src/main/java/de/blau/android/Main.java       | 27 +++++++++++--------
 src/main/java/de/blau/android/Map.java        |  2 +-
 .../java/de/blau/android/dialogs/Layers.java  |  3 ++-
 3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/src/main/java/de/blau/android/Main.java b/src/main/java/de/blau/android/Main.java
index 3bef635a6..8049f0c70 100644
--- a/src/main/java/de/blau/android/Main.java
+++ b/src/main/java/de/blau/android/Main.java
@@ -67,6 +67,7 @@
 import android.view.View.OnLongClickListener;
 import android.view.View.OnTouchListener;
 import android.view.ViewGroup;
+import android.view.ViewParent;
 import android.view.ViewStub;
 import android.widget.LinearLayout;
 import android.widget.RelativeLayout;
@@ -492,13 +493,17 @@ protected void onCreate(final Bundle savedInstanceState) {
         LinearLayout ml = (LinearLayout) getLayoutInflater().inflate(layout, null);
         mapLayout = (RelativeLayout) ml.findViewById(R.id.mainMap);
 
-        if (map != null) {
-            Log.d(DEBUG_TAG, "map exists .. destroying");
-            map.onDestroy();
+        Logic logic = App.getLogic(); // logic instance might still be around
+        map = logic != null ? logic.getMap() : null;
+        if (map == null) {
+            map = new Map(this);
+            map.setId(R.id.map_view);
+        } else {
+            ViewGroup parent = (ViewGroup) map.getParent();
+            if (parent != null) {
+                parent.removeView(map);
+            }
         }
-        map = new Map(this);
-        map.setId(R.id.map_view);
-
         // Register some Listener
         mapTouchListener = new MapTouchListener();
         map.setOnTouchListener(mapTouchListener);
@@ -585,14 +590,14 @@ protected void onCreate(final Bundle savedInstanceState) {
 
         loadOnResume = false;
 
-        if (App.getLogic() == null) {
+        if (logic == null) {
             Log.i(DEBUG_TAG, "onCreate - creating new logic");
-            App.newLogic();
+            logic = App.newLogic();
         }
         Log.i(DEBUG_TAG, "onCreate - setting new map");
 
-        App.getLogic().setPrefs(prefs);
-        App.getLogic().setMap(map, true);
+        logic.setPrefs(prefs);
+        logic.setMap(map, true);
 
         Log.d(DEBUG_TAG, "StorageDelegator dirty is " + App.getDelegator().isDirty());
         if (StorageDelegator.isStateAvailable(this) && !App.getDelegator().isDirty()) {
@@ -806,7 +811,7 @@ public void onError(@Nullable AsyncResult result) {
                     // loadStateFromFile does this above
                     App.getLogic().loadEditingState(this, setViewBox);
                 }
-                logic.loadLayerState(this, postLoadTasks);
+                // layer state should still be available if logic is still around, no need to load
                 map.invalidate();
                 checkPermissions(() -> {
                     postLoadData.onSuccess();
diff --git a/src/main/java/de/blau/android/Map.java b/src/main/java/de/blau/android/Map.java
index 2b1e0bb96..a639f6786 100755
--- a/src/main/java/de/blau/android/Map.java
+++ b/src/main/java/de/blau/android/Map.java
@@ -427,7 +427,7 @@ public MapViewLayer getLayer(int index) {
             if (index >= 0 && index < mLayers.size()) {
                 return mLayers.get(index);
             }
-            Log.e(DEBUG_TAG, "Layer for index " + index + " is null");
+            Log.e(DEBUG_TAG, "Layer for index " + index + " is null " + mLayers.size() + " layers total");
             return null;
         }
     }
diff --git a/src/main/java/de/blau/android/dialogs/Layers.java b/src/main/java/de/blau/android/dialogs/Layers.java
index dbe7ff7ce..637f6b794 100644
--- a/src/main/java/de/blau/android/dialogs/Layers.java
+++ b/src/main/java/de/blau/android/dialogs/Layers.java
@@ -420,7 +420,8 @@ protected Void doInBackground(Void param) {
      * @param map current Map
      * @param type the layer type
      */
-    private void addStyleableLayerFromFile(final FragmentActivity activity, final Preferences prefs, final Map map, @NonNull final LayerType type) {
+    private void addStyleableLayerFromFile(@NonNull final FragmentActivity activity, @NonNull final Preferences prefs, @NonNull final Map map,
+            @NonNull final LayerType type) {
         Log.d(DEBUG_TAG, "addStyleableLayerFromFile");
         SelectFile.read(activity, R.string.config_osmPreferredDir_key, new ReadFile() {
             private static final long serialVersionUID = 1L;