feat(gui): add "Go To Declaration" in menu (PR #618)

jadx-gui/src/main/java/jadx/gui/ui/codearea/CodeArea.java

@@ -96,11 +96,14 @@ public final class CodeArea extends RSyntaxTextArea {
 
 	private void addMenuItems(JClass jCls) {
 		FindUsageAction findUsage = new FindUsageAction(contentPanel, this, jCls);
+		GoToDeclarationAction goToDeclaration = new GoToDeclarationAction(contentPanel, this, jCls);
 
 		JPopupMenu popup = getPopupMenu();
 		popup.addSeparator();
 		popup.add(findUsage);
+		popup.add(goToDeclaration);
 		popup.addPopupMenuListener(findUsage);
+		popup.addPopupMenuListener(goToDeclaration);
 	}
 
 	public void loadSettings() {

jadx-gui/src/main/java/jadx/gui/ui/codearea/GoToDeclarationAction.java

@@ -0,0 +1,66 @@
+package jadx.gui.ui.codearea;
+
+import java.awt.Point;
+import java.awt.event.ActionEvent;
+
+import javax.swing.AbstractAction;
+import javax.swing.event.PopupMenuEvent;
+import javax.swing.event.PopupMenuListener;
+
+import org.fife.ui.rsyntaxtextarea.Token;
+
+import jadx.api.JavaNode;
+import jadx.gui.treemodel.JClass;
+import jadx.gui.treemodel.JNode;
+import jadx.gui.ui.MainWindow;
+import jadx.gui.utils.JumpPosition;
+import jadx.gui.utils.NLS;
+
+public final class GoToDeclarationAction extends AbstractAction implements PopupMenuListener {
+	private static final long serialVersionUID = -1186470538894941301L;
+	private final transient CodePanel contentPanel;
+	private final transient CodeArea codeArea;
+	private final transient JClass jCls;
+
+	private transient JavaNode node;
+
+	public GoToDeclarationAction(CodePanel contentPanel, CodeArea codeArea, JClass jCls) {
+		super(NLS.str("popup.go_to_declaration"));
+		this.contentPanel = contentPanel;
+		this.codeArea = codeArea;
+		this.jCls = jCls;
+	}
+
+	@Override
+	public void actionPerformed(ActionEvent e) {
+		if (node == null) {
+			return;
+		}
+		MainWindow mainWindow = contentPanel.getTabbedPane().getMainWindow();
+		JNode jNode = mainWindow.getCacheObject().getNodeCache().makeFrom(node);
+		mainWindow.getTabbedPane().codeJump(new JumpPosition(jNode, jNode.getLine()));
+	}
+
+	@Override
+	public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
+		node = null;
+		Point pos = codeArea.getMousePosition();
+		if (pos != null) {
+			Token token = codeArea.viewToToken(pos);
+			if (token != null) {
+				node = codeArea.getJavaNodeAtOffset(jCls, token.getOffset());
+			}
+		}
+		setEnabled(node != null);
+	}
+
+	@Override
+	public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
+		// do nothing
+	}
+
+	@Override
+	public void popupMenuCanceled(PopupMenuEvent e) {
+		// do nothing
+	}
+}

jadx-gui/src/main/resources/i18n/Messages_en_US.properties

@@ -136,6 +136,7 @@ popup.paste=Paste
 popup.delete=Delete
 popup.select_all=Select All
 popup.find_usage=Find Usage
+popup.go_to_declaration=Go to declaration
 popup.exclude=Exclude
 
 confirm.save_as_title=Confirm Save as

jadx-gui/src/main/resources/i18n/Messages_es_ES.properties

@@ -136,6 +136,7 @@ popup.paste=Pegar
 popup.delete=Borrar
 popup.select_all=Seleccionar todo
 #popup.find_usage=
+#popup.go_to_declaration=
 #popup.exclude=
 
 #confirm.save_as_title=

jadx-gui/src/main/resources/i18n/Messages_zh_CN.properties

@@ -136,6 +136,7 @@ popup.paste=粘贴
 popup.delete=删除
 popup.select_all=全选
 popup.find_usage=查找用例
+#popup.go_to_declaration=
 #popup.exclude=
 
 #confirm.save_as_title=