make the File > Examples link work

app/src/processing/app/ui/Welcome.java

@@ -35,10 +35,8 @@ import javax.swing.JComponent;
 import javax.swing.border.EmptyBorder;
 
 import processing.app.Base;
-import processing.app.Language;
 import processing.app.Platform;
 import processing.app.Preferences;
-import processing.awt.ShimAWT;
 
 
 public class Welcome {
@@ -74,6 +72,9 @@ public class Welcome {
     button.addActionListener(e -> view.handleClose());
     panel.add(button);
 
+    File indexFile = getIndexFile();
+    if (indexFile == null) return;  // giving up; error already printed
+
     view = new WebFrame(getIndexFile(), 420, panel) {
       /*
       @Override
@@ -97,15 +98,40 @@ public class Welcome {
       @Override
       public void handleLink(String link) {
         // The link will already have the full URL prefix
+        /*
         if (link.endsWith("#sketchbook")) {
           File folder = new File(Preferences.getSketchbookPath()).getParentFile();
           ShimAWT.selectFolder(Language.text("preferences.sketchbook_location.popup"),
                                "sketchbookCallback", folder, this);
+         */
+
+        if (link.endsWith("#examples")) {
+          base.getDefaultMode().showExamplesFrame();
+
+        } else if (link.endsWith("#mouse")) {
+          openExample("Basics/Input/Mouse2D/Mouse2D.pde");
+
+        } else if (link.endsWith("#arctan")) {
+          openExample("Basics/Math/Arctangent/Arctangent.pde");
+
+        } else if (link.endsWith("#flocking")) {
+          openExample("Topics/Simulate/Flocking/Flocking.pde");
+
+        } else if (link.endsWith("#rotating")) {
+          openExample("Demos/Graphics/RotatingArcs/RotatingArcs.pde");
+
         } else {
           super.handleLink(link);
         }
       }
 
+      private void openExample(String examplePath) {
+        File examplesFolder =
+          Platform.getContentFile("modes/java/examples");
+        File pdeFile = new File(examplesFolder, examplePath);
+        base.handleOpen(pdeFile.getAbsolutePath());
+      }
+
       @Override
       public void handleClose() {
         Preferences.setBoolean("welcome.four.seen", true);
@@ -117,14 +143,14 @@ public class Welcome {
   }
 
 
-  /** Callback for the folder selector. */
-  public void sketchbookCallback(File folder) {
-    if (folder != null) {
-      if (base != null) {
-        base.setSketchbookFolder(folder);
-      }
-    }
-  }
+//  /** Callback for the folder selector. */
+//  public void sketchbookCallback(File folder) {
+//    if (folder != null) {
+//      if (base != null) {
+//        base.setSketchbookFolder(folder);
+//      }
+//    }
+//  }
 
 
   static private File getIndexFile() {
@@ -163,13 +189,11 @@ public class Welcome {
     }
     Preferences.init();
 
-    EventQueue.invokeLater(new Runnable() {
-      public void run() {
-        try {
-          new Welcome(null);
-        } catch (IOException e) {
-          e.printStackTrace();
-        }
+    EventQueue.invokeLater(() -> {
+      try {
+        new Welcome(null);
+      } catch (IOException e) {
+        e.printStackTrace();
       }
     });
   }