Added GetLastActiveClass

To make temporary plugins work with the BCV.getCurrentlyOpenedClassNode() API, we have to store the last active class viewer in memory

There is probably a better way of doing this, but the only code using these APIs are user plugins, so it shouldn't impact the rest of the program if we have a resource mismatch

src/main/java/the/bytecode/club/bytecodeviewer/BytecodeViewer.java

@@ -350,7 +350,15 @@ public static ResourceViewer getActiveResource()
      */
     public static ClassNode getCurrentlyOpenedClassNode()
     {
-        return getActiveResource().resource.getResourceClassNode();
+        return getActiveClass().resource.getResourceClassNode();
+    }
+
+    /**
+     * Returns the currently opened & viewed resource
+     */
+    public static ResourceViewer getActiveClass()
+    {
+        return BytecodeViewer.viewer.workPane.getLastActiveClass();
     }
 
     /**

src/main/java/the/bytecode/club/bytecodeviewer/gui/resourceviewer/Workspace.java

@@ -54,13 +54,22 @@ public class Workspace extends TranslatedVisibleComponent
     public final JButton refreshClass;
     public final Set<String> openedTabs = new HashSet<>();
     public HashMap<String, ClassFileContainer> classFiles = new HashMap<>();
+    private ResourceViewer lastActiveClassViewer;
 
     public Workspace()
     {
         super("Workspace", TranslatedComponents.WORK_SPACE);
 
         this.tabs = new DraggableTabbedPane();
 
+        tabs.addChangeListener(e ->
+        {
+            ResourceViewer viewer = (ResourceViewer) tabs.getSelectedComponent();
+
+            if(viewer instanceof ClassViewer)
+                lastActiveClassViewer = viewer;
+        });
+
         // configure popup menu of close tabs
         JTabbedPanePopupMenuTabsCloser popupMenuTabsCloser = new JTabbedPanePopupMenuTabsCloser(this.tabs);
         PopupMenuTabsCloseConfiguration.Builder builder = new PopupMenuTabsCloseConfiguration.Builder();
@@ -173,6 +182,11 @@ public ResourceViewer getActiveResource()
         return (ResourceViewer) tabs.getSelectedComponent();
     }
 
+    public ResourceViewer getLastActiveClass()
+    {
+        return lastActiveClassViewer;
+    }
+
     public Component[] getLoadedViewers()
     {
         return tabs.getComponents();