altosui: Handle broken network in map tile loading

Handle missing pngfiles in AltosSetMapCache by checking ImageIO.read
for null return.

Do incremental map tile downloading asynchronously so that the UI
doesn't lock up when the network is slow

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/altosui/AltosSiteMap.java b/altosui/AltosSiteMap.java
index 5bf02e546179fbf936cdfb05c263617bb4054b84..23085f3ec5e270645b8c44760c34fb9202d61271 100644 (file)
--- a/altosui/AltosSiteMap.java
+++ b/altosui/AltosSiteMap.java
@@ -220,6 +220,16 @@ public class AltosSiteMap extends JScrollPane implements AltosFlightDisplay {
                return pngfile.toString();
        }
 
+       public void initAndFinishMapAsync (final AltosSiteMapTile tile, final Point offset) {
+               Thread thread = new Thread() {
+                               public void run() {
+                                       initMap(offset);
+                                       finishTileLater(tile, offset);
+                               }
+                       };
+               thread.start();
+       }
+
        public void setBaseLocation(double lat, double lng) {
                for (Point k : mapTiles.keySet()) {
                        AltosSiteMapTile tile = mapTiles.get(k);
@@ -308,8 +318,7 @@ public class AltosSiteMap extends JScrollPane implements AltosFlightDisplay {
 
                        AltosSiteMapTile tile = createTile(offset);
                        tile.show(state, listener_state, lref, ref);
-                       initMap(offset);
-                       finishTileLater(tile, offset);
+                       initAndFinishMapAsync(tile, offset);
                }
 
                scrollRocketToVisible(pt);
@@ -370,8 +379,7 @@ public class AltosSiteMap extends JScrollPane implements AltosFlightDisplay {
                                if (mapTiles.containsKey(offset))
                                        continue;
                                AltosSiteMapTile tile = createTile(offset);
-                               initMap(offset);
-                               finishTileLater(tile, offset);
+                               initAndFinishMapAsync(tile, offset);
                        }
                }
        }

diff --git a/altosui/AltosSiteMapCache.java b/altosui/AltosSiteMapCache.java
index 617ed4a9a3331193271b03f4dd4b56b6eb406eb3..40c8ff6bf0dc078beff6f8b5016f8910ffe2f4c4 100644 (file)
--- a/altosui/AltosSiteMapCache.java
+++ b/altosui/AltosSiteMapCache.java
@@ -19,6 +19,7 @@ package altosui;
 
 import javax.swing.*;
 import javax.imageio.ImageIO;
+import java.awt.image.*;
 import java.io.*;
 import java.net.URL;
 import java.net.URLConnection;
@@ -87,7 +88,14 @@ public class AltosSiteMapCache extends JLabel {
                }
 
                try {
-                       return new ImageIcon(ImageIO.read(pngfile));
+                       BufferedImage   img;
+
+                       img = ImageIO.read(pngfile);
+                       if (img == null) {
+                               System.out.printf("# Can't read pngfile %s\n", pngfile);
+                               return null;
+                       }
+                       return new ImageIcon(img);
                } catch (IOException e) {
                        System.out.printf("# IO error trying to load %s\n", pngfile);
                        return null;