Fixes koppor/jabref#521 - Allow to drag&drop selected bib entries to other library tabs

CHANGELOG.md

@@ -16,6 +16,7 @@ Note that this project **does not** adhere to [Semantic Versioning](http://semve
 - We added an extra option in the 'Find Unlinked Files' dialog view to ignore unnecessary files like Thumbs.db, DS_Store, etc. [koppor#373](https://github.com/koppor/jabref/issues/373)
 - JabRef now writes log files. Linux: `$home/.cache/jabref/logs/version`, Windows: `%APPDATA%\..\Local\harawata\jabref\version\logs`, Mac: `Users/.../Library/Logs/jabref/version`
 - We added an importer for Citavi backup files, support ".ctv5bak" and ".ctv6bak" file formats. [#8322](https://github.com/JabRef/jabref/issues/8322)
+- We added a feature about allowing drag selected entries and drop them to other opened inactive library tabs.
 
 ### Changed
 

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

@@ -222,6 +222,54 @@ private void initDragAndDrop() {
                 } else {
                     tabbedPane.getTabs().remove(dndIndicator);
                 }
+                // Accept drag entries from MainTable
+                if (event.getDragboard().hasContent(DragAndDropDataFormats.ENTRIES)) {
+                    event.acceptTransferModes(TransferMode.COPY);
+                    event.consume();
+                }
+            });
+
+            this.getScene().setOnDragEntered(event -> {
+                // It is necessary to setOnDragOver for newly opened tabs
+                // drag'n'drop on tabs covered dnd on tabbedPane, so dnd on tabs should contain all dnds on tabbedPane
+                tabbedPane.lookupAll(".tab").forEach(t -> {
+                    t.setOnDragOver(tabDragEvent -> {
+                        if (DragAndDropHelper.hasBibFiles(tabDragEvent.getDragboard())) {
+                            tabDragEvent.acceptTransferModes(TransferMode.ANY);
+                            if (!tabbedPane.getTabs().contains(dndIndicator)) {
+                                tabbedPane.getTabs().add(dndIndicator);
+                            }
+                            event.consume();
+                        } else {
+                            tabbedPane.getTabs().remove(dndIndicator);
+                        }
+
+                        if (tabDragEvent.getDragboard().hasContent(DragAndDropDataFormats.ENTRIES)) {
+                            tabDragEvent.acceptTransferModes(TransferMode.COPY);
+                            tabDragEvent.consume();
+                        }
+                    });
+                    t.setOnDragExited(event1 -> tabbedPane.getTabs().remove(dndIndicator));
+                    t.setOnDragDropped(tabDragEvent -> {
+                        if (DragAndDropHelper.hasBibFiles(tabDragEvent.getDragboard())) {
+                            tabbedPane.getTabs().remove(dndIndicator);
+                            List<Path> bibFiles = DragAndDropHelper.getBibFiles(tabDragEvent.getDragboard());
+                            OpenDatabaseAction openDatabaseAction = this.getOpenDatabaseAction();
+                            openDatabaseAction.openFiles(bibFiles, true);
+                            tabDragEvent.setDropCompleted(true);
+                            tabDragEvent.consume();
+                        } else {
+                            for (Tab libraryTab : tabbedPane.getTabs()) {
+                                if (libraryTab.getId().equals(t.getId()) &&
+                                        !tabbedPane.getSelectionModel().getSelectedItem().equals(libraryTab)) {
+                                    ((LibraryTab) libraryTab).dropEntry(stateManager.getLocalDragboard().getBibEntries());
+                                }
+                            }
+                            tabDragEvent.consume();
+                        }
+                    });
+                });
+                event.consume();
             });
 
             this.getScene().setOnDragExited(event -> tabbedPane.getTabs().remove(dndIndicator));

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

@@ -7,6 +7,7 @@
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Random;
 
 import javafx.animation.PauseTransition;
 import javafx.application.Platform;
@@ -153,6 +154,10 @@ public LibraryTab(JabRefFrame frame,
 
         this.entryEditor = new EntryEditor(this, externalFileTypes);
 
+        // set LibraryTab ID for drag'n'drop
+        // ID content doesn't matter, we only need different tabs to have different ID
+        this.setId(Long.valueOf(new Random().nextLong()).toString());
+
         Platform.runLater(() -> {
             EasyBind.subscribe(changedProperty, this::updateTabTitle);
             stateManager.getOpenDatabases().addListener((ListChangeListener<BibDatabaseContext>) c ->
@@ -758,6 +763,10 @@ public void paste() {
         mainTable.paste();
     }
 
+    public void dropEntry(List<BibEntry> entriesToAdd) {
+        mainTable.dropEntry(entriesToAdd);
+    }
+
     public void cut() {
         mainTable.cut();
     }

src/main/java/org/jabref/gui/maintable/MainTable.java

@@ -314,6 +314,12 @@ public void paste() {
         }
     }
 
+    public void dropEntry(List<BibEntry> entriesToAdd) {
+        for (BibEntry entry : entriesToAdd) {
+            importHandler.importEntryWithDuplicateCheck(database, (BibEntry) entry.clone());
+        }
+    }
+
     private void handleOnDragOver(TableRow<BibEntryTableViewModel> row, BibEntryTableViewModel item, DragEvent event) {
         if (event.getDragboard().hasFiles()) {
             event.acceptTransferModes(TransferMode.ANY);
@@ -350,8 +356,9 @@ private void handleOnDragDetected(TableRow<BibEntryTableViewModel> row, BibEntry
 
         // The following is necesary to initiate the drag and drop in javafx, although we don't need the contents
         // It doesn't work without
+        // Drag'n'drop to other tabs use COPY TransferMode, drop to group sidepane use MOVE
         ClipboardContent content = new ClipboardContent();
-        Dragboard dragboard = startDragAndDrop(TransferMode.MOVE);
+        Dragboard dragboard = startDragAndDrop(TransferMode.COPY_OR_MOVE);
         content.put(DragAndDropDataFormats.ENTRIES, "");
         dragboard.setContent(content);