Improve Document Viewer error handling and state management

CHANGELOG.md

@@ -59,6 +59,7 @@ Note that this project **does not** adhere to [Semantic Versioning](https://semv
 - We fixed an issue where the preview area in the "Select Style" dialog of the LibreOffice integration was too small to display full content. [#13051](https://github.com/JabRef/jabref/issues/13051)
 - We fixed an issue where the tab showing the fulltext search results was not displayed. [#12865](https://github.com/JabRef/jabref/issues/12865)
 - We fixed an issue showing an empty tooltip in maintable. [#11681](https://github.com/JabRef/jabref/issues/11681)
+- We fixed an issue where Document Viewer showed technical exceptions when opening entries with non-PDF files. [#13198](https://github.com/JabRef/jabref/issues/13198)
 
 ### Removed
 

jabgui/src/main/java/org/jabref/gui/documentviewer/DocumentViewerView.java

@@ -88,7 +88,7 @@ private void setupFileChoice() {
         // This also automatically selects the first file on the initial load
         Stage stage = (Stage) getDialogPane().getScene().getWindow();
         fileChoice.itemsProperty().addListener((observable, oldValue, newValue) -> {
-            if (newValue.isEmpty()) {
+            if (newValue == null || newValue.isEmpty()) {
                 stage.close();
             } else {
                 fileChoice.getSelectionModel().selectFirst();
@@ -99,9 +99,8 @@ private void setupFileChoice() {
 
     private void setupViewer() {
         viewModel.currentDocumentProperty().addListener((observable, oldDocument, newDocument) -> {
-            if (newDocument != null) {
-                viewer.show(newDocument);
-            }
+            // Always call show(), even when newDocument is null
+            viewer.show(newDocument);
         });
         viewModel.currentPageProperty().bindBidirectional(viewer.currentPageProperty());
         viewModel.highlightTextProperty().bindBidirectional(viewer.highlightTextProperty());

jabgui/src/main/java/org/jabref/gui/documentviewer/DocumentViewerViewModel.java

@@ -26,6 +26,9 @@
 import org.jabref.model.entry.BibEntry;
 import org.jabref.model.entry.LinkedFile;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 public class DocumentViewerViewModel extends AbstractViewModel {
 
     private final StateManager stateManager;
@@ -35,6 +38,7 @@ public class DocumentViewerViewModel extends AbstractViewModel {
     private final BooleanProperty liveMode = new SimpleBooleanProperty(true);
     private final IntegerProperty currentPage = new SimpleIntegerProperty();
     private final StringProperty highlightText = new SimpleStringProperty();
+    private final Logger LOGGER = LoggerFactory.getLogger(DocumentViewerViewModel.class);
 
     public DocumentViewerViewModel(StateManager stateManager, CliPreferences preferences) {
         this.stateManager = Objects.requireNonNull(stateManager);
@@ -76,10 +80,25 @@ public StringProperty highlightTextProperty() {
     private void setCurrentEntries(List<BibEntry> entries) {
         if (entries.isEmpty()) {
             files.clear();
+            currentDocument.set(null); // Clear current document when no entries
         } else {
-            Set<LinkedFile> linkedFiles = entries.stream().map(BibEntry::getFiles).flatMap(List::stream).collect(Collectors.toSet());
-            // We don't need to switch to the first file, this is done automatically in the UI part
-            files.setValue(FXCollections.observableArrayList(linkedFiles));
+            Set<LinkedFile> pdfFiles = entries.stream()
+                                              .map(BibEntry::getFiles)
+                                              .flatMap(List::stream)
+                                              .filter(this::isPdfFile)  // 直接在这里过滤
+                                              .collect(Collectors.toSet());
+
+            if (pdfFiles.isEmpty()) {
+                // No PDF files found - clear the list and current document
+                files.clear();
+                currentDocument.set(null);
+                // The UI will automatically close the dialog when files list is empty
+                // This provides better UX than showing technical errors
+            } else {
+                // We have PDF files - display them in the dropdown
+                files.setValue(FXCollections.observableArrayList(pdfFiles));
+                // The first file will be automatically selected by the UI
+            }
         }
     }
 
@@ -89,11 +108,34 @@ private void setCurrentDocument(Path path) {
         }
     }
 
+    private boolean isPdfFile(LinkedFile file) {
+        if (file == null || file.getLink() == null || file.getLink().trim().isEmpty()) {
+            return false;
+        }
+
+        try {
+            Path filePath = Path.of(file.getLink());
+            return FileUtil.isPDFFile(filePath);
+        } catch (Exception e) {
+            return false;
+        }
+    }
+
     public void switchToFile(LinkedFile file) {
         if (file != null) {
             stateManager.getActiveDatabase()
                         .flatMap(database -> file.findIn(database, preferences.getFilePreferences()))
-                        .ifPresent(this::setCurrentDocument);
+                        .ifPresentOrElse(
+                                this::setCurrentDocument,
+                                () -> {
+                                    // File not found or cannot be accessed - clear current document
+                                    currentDocument.set(null);
+                                    LOGGER.warn("Could not find or access file: {}", file.getLink());
+                                }
+                        );
+        } else {
+            // File is null - clear current document to ensure UI consistency
+            currentDocument.set(null);
         }
     }
 

jabgui/src/main/java/org/jabref/gui/documentviewer/PdfDocumentViewer.java

@@ -8,6 +8,8 @@
 import javafx.beans.property.SimpleIntegerProperty;
 import javafx.beans.property.SimpleStringProperty;
 import javafx.beans.property.StringProperty;
+import javafx.geometry.Pos;
+import javafx.scene.control.Label;
 import javafx.scene.layout.StackPane;
 
 import com.dlsc.pdfviewfx.PDFView;
@@ -25,13 +27,27 @@ public class PdfDocumentViewer extends StackPane {
     private final PDFView pdfView;
     private final IntegerProperty currentPage = new SimpleIntegerProperty(0);
     private final StringProperty highlightText = new SimpleStringProperty("");
+    private final Label placeholderLabel;
 
     public PdfDocumentViewer() {
         pdfView = new PDFView();
-        getChildren().add(pdfView);
+
+        // Create placeholder label
+        placeholderLabel = new Label("No PDF available for preview");
+        placeholderLabel.setStyle("-fx-text-fill: #666666; -fx-font-size: 16px;");
+        placeholderLabel.setAlignment(Pos.CENTER);
+
+        getChildren().addAll(pdfView, placeholderLabel);
+
+        // Initially show placeholder
+        pdfView.setVisible(false);
+        placeholderLabel.setVisible(true);
+
         EasyBind.subscribe(currentPage, current -> pdfView.setPage(current.intValue()));
         // We can only set the search query at the moment not the results or mark them in the text
         EasyBind.subscribe(highlightText, pdfView::setSearchText);
+        // Initially hide PDFView until a document is loaded
+        pdfView.setVisible(false);
     }
 
     public IntegerProperty currentPageProperty() {
@@ -47,11 +63,23 @@ public void show(Path document) {
             try {
                 pdfView.load(Files.newInputStream(document));
                 pdfView.setPage(currentPage.get());
+                // Show PDF and hide placeholder
+                pdfView.setVisible(true);
+                placeholderLabel.setVisible(false);
+                LOGGER.debug("Successfully loaded PDF document: {}", document);
             } catch (IOException e) {
                 LOGGER.error("Could not load PDF document {}", document, e);
+                // Show error message
+                pdfView.setVisible(false);
+                placeholderLabel.setText("Could not load PDF: " + document.getFileName());
+                placeholderLabel.setVisible(true);
             }
         } else {
-            LOGGER.error("Could not load PDF document: no document found");
+            LOGGER.debug("No document provided to viewer, showing placeholder");
+            // Show placeholder and hide PDF
+            pdfView.setVisible(false);
+            placeholderLabel.setText("No PDF available for preview");
+            placeholderLabel.setVisible(true);
         }
     }
 }