Add welcome screen to JabRef GUI that displays when no database/library is open

CHANGELOG.md

@@ -34,6 +34,7 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 - We added a different background color to the search bar to indicate when the search syntax is wrong. [#11658](https://github.com/JabRef/jabref/pull/11658)
 - We added a setting which always adds the literal "Cited on pages" text before each JStyle citation. [#11691](https://github.com/JabRef/jabref/pull/11732)
 - We added a new plain citation parser that uses LLMs. [#11825](https://github.com/JabRef/jabref/issues/11825)
+- We added a welcome screen that displays when no database is open [koppor#96](https://github.com/koppor/jabref/issues/96)
 - We added a compare button to the duplicates in the citation relations tab to open the "Possible duplicate entries" window. [#11192](https://github.com/JabRef/jabref/issues/11192)
 - We added automatic browser extension install on Windows for Chrome and Edge. [#6076](https://github.com/JabRef/jabref/issues/6076)
 - We added a search bar for filtering keyboard shortcuts. [#11686](https://github.com/JabRef/jabref/issues/11686)

src/main/java/org/jabref/gui/Base.css

@@ -1732,5 +1732,25 @@ We want to have a look that matches our icons in the tool-bar */
     -fx-effect: dropshadow(three-pass-box, rgba(0, 0, 0, 0.6), 8, 0.0, 0, 0);
 }
 
+/* Welcome Page Styles */
+.welcome-label {
+    -fx-font-size: 40px;
+    -fx-text-fill: -jr-theme-text;
+    -fx-font-family: "Arial";
+}
+
+.welcome-text {
+    -fx-font-size: 22px;
+    -fx-text-fill: -jr-gray-3;
+}
+
+.welcome-hyperlink {
+    -fx-font-size: 22px;
+    -fx-text-fill: -jr-theme;
+}
+
+.welcome-hyperlink:visited {
+    -fx-text-fill: -jr-theme;
+}
 
 /* endregion */

src/main/java/org/jabref/gui/JabRefGUI.java

@@ -86,12 +86,10 @@ public static void setup(List<UiCommand> uiCommands,
     public void start(Stage stage) {
         this.mainStage = stage;
 
-        FallbackExceptionHandler.installExceptionHandler((exception, thread) -> {
-            UiTaskExecutor.runInJavaFXThread(() -> {
-                DialogService dialogService = Injector.instantiateModelOrService(DialogService.class);
-                dialogService.showErrorDialogAndWait("Uncaught exception occurred in " + thread, exception);
-            });
-        });
+        FallbackExceptionHandler.installExceptionHandler((exception, thread) -> UiTaskExecutor.runInJavaFXThread(() -> {
+            DialogService dialogService = Injector.instantiateModelOrService(DialogService.class);
+            dialogService.showErrorDialogAndWait("Uncaught exception occurred in " + thread, exception);
+        }));
 
         initialize();
 

src/main/java/org/jabref/gui/frame/JabRefFrame.java

@@ -21,6 +21,7 @@
 import javafx.scene.control.TabPane;
 import javafx.scene.input.KeyEvent;
 import javafx.scene.layout.BorderPane;
+import javafx.scene.layout.StackPane;
 import javafx.scene.layout.VBox;
 import javafx.stage.Stage;
 
@@ -45,6 +46,7 @@
 import org.jabref.gui.sidepane.SidePane;
 import org.jabref.gui.sidepane.SidePaneType;
 import org.jabref.gui.undo.CountingUndoManager;
+import org.jabref.gui.util.WelcomePage;
 import org.jabref.logic.UiCommand;
 import org.jabref.logic.ai.AiService;
 import org.jabref.logic.journals.JournalAbbreviationRepository;
@@ -99,6 +101,9 @@ public class JabRefFrame extends BorderPane implements LibraryTabContainer, UiMe
 
     private Subscription dividerSubscription;
 
+    private final WelcomePage welcomePage;
+    private final StackPane contentPane = new StackPane();  // Holds both WelcomePage and TabPane
+
     public JabRefFrame(Stage mainStage,
                        DialogService dialogService,
                        FileUpdateMonitor fileUpdateMonitor,
@@ -120,6 +125,19 @@ public JabRefFrame(Stage mainStage,
         this.clipBoardManager = clipBoardManager;
         this.taskExecutor = taskExecutor;
 
+        this.welcomePage = new WelcomePage(
+                this,
+                preferences,
+                aiService,
+                dialogService,
+                stateManager,
+                fileUpdateMonitor,
+                entryTypesManager,
+                undoManager,
+                clipBoardManager,
+                taskExecutor
+        );
+
         setId("frame");
 
         // Create components
@@ -181,10 +199,13 @@ public JabRefFrame(Stage mainStage,
             }
         });
 
+        // Initialize layout and bindings
         initLayout();
         initKeyBindings();
         frameDndHandler.initDragAndDrop();
         initBindings();
+        bindDatabaseChanges();
+        updateContent();
     }
 
     private void initLayout() {
@@ -223,12 +244,42 @@ private void initLayout() {
         head.setSpacing(0d);
         setTop(head);
 
-        splitPane.getItems().addAll(tabbedPane);
+        contentPane.getChildren().addAll(welcomePage, tabbedPane);
+        splitPane.getItems().add(contentPane);
+
         SplitPane.setResizableWithParent(sidePane, false);
         sidePane.widthProperty().addListener(c -> updateSidePane());
         sidePane.getChildren().addListener((InvalidationListener) c -> updateSidePane());
-        updateSidePane();
+
         setCenter(splitPane);
+        updateContent();  // Ensure layout is consistent on load
+    }
+
+    private void updateContent() {
+        boolean hasOpenDatabases = !stateManager.getOpenDatabases().isEmpty();
+
+        // Toggle visibility between welcome page and tabbed pane
+        welcomePage.setVisible(!hasOpenDatabases);
+        tabbedPane.setVisible(hasOpenDatabases);
+
+        if (hasOpenDatabases) {
+            if (!splitPane.getItems().contains(sidePane)) {
+                sidePane.setPrefWidth(260);
+                splitPane.getItems().addFirst(sidePane);
+
+                // Ensure divider position is set before rendering
+                splitPane.setDividerPositions(0.2);
+
+                // Ensure smooth transition by updating the layout immediately
+                Platform.runLater(() -> splitPane.setDividerPositions(0.2));
+            }
+        } else {
+            splitPane.getItems().remove(sidePane);
+        }
+    }
+
+    private void bindDatabaseChanges() {
+        stateManager.getOpenDatabases().addListener((InvalidationListener) obs -> Platform.runLater(this::updateContent));
     }
 
     private void updateSidePane() {
@@ -446,12 +497,31 @@ public void addTab(@NonNull BibDatabaseContext databaseContext, boolean raisePan
 
     public void addTab(@NonNull LibraryTab libraryTab, boolean raisePanel) {
         tabbedPane.getTabs().add(libraryTab);
+
         if (raisePanel) {
             tabbedPane.getSelectionModel().select(libraryTab);
             tabbedPane.requestFocus();
         }
 
         libraryTab.setContextMenu(createTabContextMenuFor(libraryTab));
+
+        // Ensure layout is updated
+        updateContent();
+        updateSidePane();
+
+        // Set the preferred width and divider position explicitly
+        sidePane.setPrefWidth(260);
+        Platform.runLater(() -> {
+            if (!sidePane.getChildren().isEmpty() && !splitPane.getItems().contains(sidePane)) {
+                splitPane.getItems().addFirst(sidePane);
+
+                // Force divider to a known position (e.g., 0.2 of the total width)
+                LOGGER.info("Forcing divider position after adding tab.");
+                splitPane.setDividerPositions(0.2);
+
+                updateDividerPosition();  // Ensure any further updates are applied
+            }
+        });
     }
 
     private ContextMenu createTabContextMenuFor(LibraryTab tab) {

src/main/java/org/jabref/gui/util/WelcomePage.java

@@ -0,0 +1,75 @@
+package org.jabref.gui.util;
+
+import javafx.geometry.Pos;
+import javafx.scene.control.Hyperlink;
+import javafx.scene.control.Label;
+import javafx.scene.layout.VBox;
+import javafx.scene.text.Text;
+import javafx.scene.text.TextAlignment;
+import javafx.scene.text.TextFlow;
+
+import org.jabref.gui.ClipBoardManager;
+import org.jabref.gui.DialogService;
+import org.jabref.gui.StateManager;
+import org.jabref.gui.frame.JabRefFrame;
+import org.jabref.gui.importer.NewDatabaseAction;
+import org.jabref.gui.importer.actions.OpenDatabaseAction;
+import org.jabref.gui.preferences.GuiPreferences;
+import org.jabref.gui.undo.CountingUndoManager;
+import org.jabref.logic.ai.AiService;
+import org.jabref.logic.util.TaskExecutor;
+import org.jabref.model.entry.BibEntryTypesManager;
+import org.jabref.model.util.FileUpdateMonitor;
+
+/**
+ * A simple Welcome Page for the JabRef application.
+ */
+public class WelcomePage extends VBox {
+
+    public WelcomePage(JabRefFrame frame,
+                       GuiPreferences preferences,
+                       AiService aiService,
+                       DialogService dialogService,
+                       StateManager stateManager,
+                       FileUpdateMonitor fileUpdateMonitor,
+                       BibEntryTypesManager entryTypesManager,
+                       CountingUndoManager undoManager,
+                       ClipBoardManager clipBoardManager,
+                       TaskExecutor taskExecutor) {
+
+        setAlignment(Pos.CENTER);
+        setSpacing(10);
+
+        // Title
+        Label welcomeLabel = new Label("Welcome to JabRef!");
+        welcomeLabel.getStyleClass().add("welcome-label");
+
+        // Text and hyperlink for "New Library"
+        Text openNewLibraryText = new Text("Open a ");
+        openNewLibraryText.getStyleClass().add("welcome-text");
+
+        Hyperlink newLibraryLink = new Hyperlink("New Library");
+        newLibraryLink.getStyleClass().add("welcome-hyperlink");
+        newLibraryLink.setOnAction(e -> new NewDatabaseAction(frame, preferences).execute());
+
+        // Text and hyperlink for "Open Library"
+        Hyperlink openLibraryLink = new Hyperlink("Existing Library");
+        openLibraryLink.getStyleClass().add("welcome-hyperlink");
+        openLibraryLink.setOnAction(e -> new OpenDatabaseAction(frame, preferences, aiService, dialogService,
+                stateManager, fileUpdateMonitor, entryTypesManager, undoManager, clipBoardManager,
+                taskExecutor).execute());
+
+        Text orExistingDatabaseText = new Text(" or open an ");
+        orExistingDatabaseText.getStyleClass().add("welcome-text");
+
+        // TextFlows for each section
+        TextFlow newLibraryFlow = new TextFlow(openNewLibraryText, newLibraryLink);
+        newLibraryFlow.setTextAlignment(TextAlignment.CENTER);
+
+        TextFlow openLibraryFlow = new TextFlow(orExistingDatabaseText, openLibraryLink);
+        openLibraryFlow.setTextAlignment(TextAlignment.CENTER);
+
+        // Add elements to the VBox
+        getChildren().addAll(welcomeLabel, newLibraryFlow, openLibraryFlow);
+    }
+}