Use last style values as defaults and generate new colours for additional layers of the same type

src/main/java/de/blau/android/Map.java

@@ -266,7 +266,7 @@ public void setUpLayers(@NonNull Context ctx) {
                             layer = new de.blau.android.layer.tasks.MapOverlay(this);
                             break;
                         case GEOJSON:
-                            layer = new de.blau.android.layer.geojson.MapOverlay(this);
+                            layer = new de.blau.android.layer.geojson.MapOverlay(this, contentId);
                             if (!((de.blau.android.layer.geojson.MapOverlay) layer).loadGeoJsonFile(ctx, Uri.parse(contentId), true)) {
                                 // other error, has already been toasted
                                 layer = null; // this will delete the layer
@@ -376,6 +376,24 @@ private List<MapViewLayer> getLayers(@NonNull LayerType type, @Nullable String c
         return result;
     }
 
+    /**
+     * Get a count of layers of a specific type
+     * 
+     * @param type the LayerType
+     * @return a count
+     */
+    public int getLayerTypeCount(@NonNull LayerType type) {
+        int count = 0;
+        synchronized (mLayers) {
+            for (MapViewLayer l : mLayers) {
+                if (l.getType().equals(type)) {
+                    count++;
+                }
+            }
+        }
+        return count;
+    }
+
     /**
      * Get the list of configured layers
      * 

src/main/java/de/blau/android/Splash.java

@@ -126,7 +126,9 @@ protected Void doInBackground(Void param) {
             }
             // read Presets here to avoid reading them on UI thread on startup of Main
             Progress.showDialog(Splash.this, Progress.PROGRESS_LOADING_PRESET);
+            Log.d(DEBUG_TAG, "Initial preset load");
             App.getCurrentPresets(Splash.this);
+            Log.d(DEBUG_TAG, "Preset load finished");
             //
             Intent intent = new Intent(Splash.this, Main.class);
             intent.putExtra(SHORTCUT_EXTRAS_KEY, shortcutExtras);

src/main/java/de/blau/android/dialogs/Layers.java

@@ -436,7 +436,6 @@ private void addStyleableLayerFromUri(@NonNull final FragmentActivity activity,
             map.setUpLayers(activity);
             layer = (de.blau.android.layer.StyleableLayer) map.getLayer(type, uriString);
             if (layer != null) { // if null setUpLayers will have toasted
-                layer.resetStyling();
                 LayerStyle.showDialog(activity, layer.getIndex());
                 SelectFile.savePref(prefs, R.string.config_osmPreferredDir_key, fileUri);
                 layer.invalidate();

src/main/java/de/blau/android/layer/StyleableFileLayer.java

@@ -0,0 +1,59 @@
+package de.blau.android.layer;
+
+import java.io.InputStream;
+
+import android.content.Context;
+import android.net.Uri;
+import androidx.annotation.NonNull;
+import de.blau.android.contract.FileExtensions;
+import de.blau.android.util.Hash;
+
+/**
+ * StyleableLayer that is loaded from a file
+ * 
+ * @author simon
+ *
+ */
+public abstract class StyleableFileLayer extends StyleableLayer {
+
+    private static final long serialVersionUID = 1L;
+
+    /**
+     * State file file name
+     */
+    protected String stateFileName;
+
+    protected String contentId; // could potentially be transient
+
+    protected StyleableFileLayer(@NonNull String contentId, String defaultStateFileName) {
+        this.contentId = contentId;
+        this.stateFileName = defaultStateFileName;
+    }
+
+    /**
+     * Check if we have a state file
+     * 
+     * @param context an Android Context
+     * @return true if a state file exists
+     */
+    protected boolean hasStateFile(@NonNull Context context) {
+        setStateFileName(Uri.parse(contentId).getEncodedPath());
+        try (InputStream stream = context.openFileInput(stateFileName)) {
+            return true;
+        } catch (Exception ex) {
+            return false;
+        }
+    }
+
+    /**
+     * Set the name of the state file
+     * 
+     * This needs to be unique across all instances so best an encoded uri, to avoid filename length issues we use the
+     * SHA-256 hash
+     * 
+     * @param baseName the base name for this specific instance
+     */
+    protected void setStateFileName(@NonNull String baseName) {
+        stateFileName = Hash.sha256(baseName) + "." + FileExtensions.RES;
+    }
+}

src/main/java/de/blau/android/layer/geojson/MapOverlay.java

@@ -55,21 +55,23 @@
 import de.blau.android.layer.LabelMinZoomInterface;
 import de.blau.android.layer.LayerInfoInterface;
 import de.blau.android.layer.LayerType;
+import de.blau.android.layer.StyleableFileLayer;
 import de.blau.android.layer.StyleableLayer;
 import de.blau.android.osm.BoundingBox;
 import de.blau.android.osm.OsmXml;
 import de.blau.android.osm.Server;
 import de.blau.android.osm.ViewBox;
+import de.blau.android.prefs.Preferences;
 import de.blau.android.resources.DataStyle;
 import de.blau.android.resources.DataStyle.FeatureStyle;
 import de.blau.android.resources.symbols.TriangleDown;
+import de.blau.android.util.ColorUtil;
 import de.blau.android.util.ContentResolverUtil;
 import de.blau.android.util.ExecutorTask;
 import de.blau.android.util.FileUtil;
 import de.blau.android.util.GeoJSONConstants;
 import de.blau.android.util.GeoJson;
 import de.blau.android.util.GeoMath;
-import de.blau.android.util.Hash;
 import de.blau.android.util.SavingHelper;
 import de.blau.android.util.SerializableTextPaint;
 import de.blau.android.util.Snack;
@@ -78,7 +80,7 @@
 import de.blau.android.util.rtree.RTree;
 import de.blau.android.views.IMapView;
 
-public class MapOverlay extends StyleableLayer
+public class MapOverlay extends StyleableFileLayer
         implements Serializable, ExtentInterface, DiscardInterface, ClickableInterface<Feature>, LayerInfoInterface, LabelMinZoomInterface {
 
     private static final long serialVersionUID = 4L;
@@ -182,19 +184,20 @@ private void readObject(java.io.ObjectInputStream in) throws IOException, ClassN
      */
     private String uri;
 
-    /**
-     * State file file name
-     */
-    private String stateFileName = FILENAME;
-
     /**
      * Construct this layer
      * 
      * @param map the Map object we are displayed on
+     * @param contentId the id for the current contents
      */
-    public MapOverlay(final Map map) {
+    public MapOverlay(@NonNull final Map map, @NonNull String contentId) {
+        super(contentId, FILENAME);
         this.map = map;
-        resetStyling();
+        final Preferences prefs = map.getPrefs();
+        initStyling(!hasStateFile(map.getContext()), prefs.getGeoJsonStrokeWidth(), prefs.getGeoJsonLabelSource(), prefs.getGeoJsonLabelMinZoom(),
+                prefs.getGeoJsonSynbol());
+        paint.setColor(
+                ColorUtil.generateColor(map.getLayerTypeCount(LayerType.GEOJSON), 9, DataStyle.getInternal(DataStyle.GEOJSON_DEFAULT).getPaint().getColor()));
     }
 
     @Override
@@ -418,7 +421,7 @@ protected Boolean doInBackground(Void arg) {
                         if (name == null) {
                             name = uri.getLastPathSegment();
                         }
-                        setFileName(uri.getEncodedPath());
+                        setStateFileName(uri.getEncodedPath());
                         MapOverlay.this.uri = uri.toString();
                         return loadGeoJsonFile(ctx, is, fromState);
                     } catch (SecurityException sex) {
@@ -442,17 +445,6 @@ protected Boolean doInBackground(Void arg) {
         }
     }
 
-    /**
-     * Set the name of the state file
-     * 
-     * This needs to be unique across all instances so best an encoded uri
-     * 
-     * @param baseName the base name for this specific instance
-     */
-    private void setFileName(@NonNull String baseName) {
-        stateFileName = Hash.sha256(baseName) + "." + FileExtensions.RES;
-    }
-
     /**
      * Read an InputStream containing GeoJSON data in to the layer, replacing any existing data
      * 
@@ -707,41 +699,65 @@ public List<Feature> getFeatures() {
 
     @Override
     public void resetStyling() {
+        initStyling(true, DataStyle.DEFAULT_GEOJSON_STROKE_WIDTH, "", Map.SHOW_LABEL_LIMIT, TriangleDown.NAME);
+    }
+
+    /**
+     * Init the styling to the provided values
+     * 
+     * @param style if true set styling
+     * @param strokeWidth the stroke width
+     * @param labelKey the source of the label
+     * @param labelMinZoom min. zoom from on we show the label
+     * @param symbolName the name of the point symbol
+     */
+    private void initStyling(boolean style, float strokeWidth, @NonNull String labelKey, int labelMinZoom, String symbolName) {
         paint = new SerializableTextPaint(DataStyle.getInternal(DataStyle.GEOJSON_DEFAULT).getPaint());
-        labelKey = "";
-        labelMinZoom = Map.SHOW_LABEL_LIMIT;
         iconRadius = map.getIconRadius();
         marker = DataStyle.getCurrent().getSymbol(TriangleDown.NAME);
+        if (style) {
+            setStrokeWidth(strokeWidth);
+            setLabel(labelKey);
+            setLabelMinZoom(labelMinZoom);
+            setPointSymbol(symbolName);
+        }
     }
 
     @Override
     public List<String> getLabelList() {
-        if (data != null) {
-            Collection<BoundedFeature> queryResult = new ArrayList<>();
-            data.query(queryResult);
-            Set<String> result = new TreeSet<>();
-            for (BoundedFeature bf : queryResult) {
-                Feature feature = bf.getFeature();
-                if (feature != null) {
-                    JsonObject properties = feature.properties();
-                    if (properties != null) {
-                        for (String key : properties.keySet()) {
-                            JsonElement e = properties.get(key);
-                            if (e != null && e.isJsonPrimitive()) {
-                                result.add(key);
-                            }
-                        }
-                    }
+        if (data == null) {
+            return super.getLabelList();
+        }
+        Collection<BoundedFeature> queryResult = new ArrayList<>();
+        data.query(queryResult);
+        Set<String> result = new TreeSet<>();
+        for (BoundedFeature bf : queryResult) {
+            Feature feature = bf.getFeature();
+            JsonObject properties = feature != null ? feature.properties() : null;
+            if (properties == null) {
+                continue;
+            }
+            for (String key : properties.keySet()) {
+                JsonElement e = properties.get(key);
+                if (e != null && e.isJsonPrimitive()) {
+                    result.add(key);
                 }
             }
-            return new ArrayList<>(result);
+
         }
-        return super.getLabelList();
+        return new ArrayList<>(result);
+    }
+
+    @Override
+    public void setStrokeWidth(float width) {
+        super.setStrokeWidth(width);
+        map.getPrefs().setGeoJsonStrokeWidth(width);
     }
 
     @Override
     public void setLabel(String key) {
         labelKey = key;
+        map.getPrefs().setGeoJsonLabelSource(key);
     }
 
     @Override
@@ -752,13 +768,20 @@ public String getLabel() {
     @Override
     public void setLabelMinZoom(int minZoom) {
         labelMinZoom = minZoom;
+        map.getPrefs().setGeoJsonLabelMinZoom(minZoom);
     }
 
     @Override
     public int getLabelMinZoom() {
         return labelMinZoom;
     }
 
+    @Override
+    public void setPointSymbol(@NonNull String symbol) {
+        super.setPointSymbol(symbol);
+        map.getPrefs().setGeoJsonSymbol(symbol);
+    }
+
     /**
      * Get the label value for this Feature
      *