Question

For a simple Swing application for merging PDFs with Apache PDFBox I’m using a JFileChooser to select one or multiple PDF files and add it/them to a JList.
No problems so far.

What bothers me is that the previous selection persists in the JFileChooser when I click the button to add another file/files again, I do not want this, the selection should initially be empty.

I tried this but it neither works nor throws an exception:

    pdfFileChooser.setSelectedFile(null);

Here is the relevant code:

    pdfFileChooser.setAcceptAllFileFilterUsed(false);
    pdfFileChooser.setMultiSelectionEnabled(true);
    pdfFileChooser.setFileFilter(new FileFilter() {

       @Override
       public boolean accept(File arg0) {
          return arg0.getName().endsWith(".pdf");
       }
       @Override
       public String getDescription() {
          return "*.pdf";
       }
    } );

    JButton btnAddFile = new JButton("Add file");
    btnAddFile.addActionListener(new ActionListener() {
       public void actionPerformed(ActionEvent arg0) {
          if(pdfFileChooser.showOpenDialog(frame) == JFileChooser.APPROVE_OPTION) {
             addFileToList(pdfFileChooser.getSelectedFiles());
             pdfFileChooser.setSelectedFile(null);
          }
       }
    });

    private void addFileToList(File[] filesToAdd) {
       if((filesToAdd != null) && (filesToAdd.length > 0)) {
          DefaultListModel model = (DefaultListModel)listFiles.getModel();
          for(File file : filesToAdd) {
             if(!model.contains(file)) {
                model.addElement(file);                 
             }
          }
       }
    }

How can I remove the selection from the JFileChooser so no file/files is/are initially selected?

Answer 1

This is, IMHO, a bug.

(As has been kindly pointed out, “bug” might be to strong a word as the API does not state what would happen if you passed null to the selectedFile method. Instead, it’s probably more reasonable to suggest that it is a missing feature)

Try something like this…

JFileChooser fc = new JFileChooser();
fc.showOpenDialog(null);
File selected = fc.getSelectedFile();
System.out.println("You selected " + selected);

File currentDirectory = fc.getCurrentDirectory();
// Hack alert
fc.setSelectedFile(new File(""));
fc.setCurrentDirectory(currentDirectory);

fc.showOpenDialog(null);
selected = fc.getSelectedFile();

System.out.println("You selected " + selected);

Basically, the change of the selected file seems to be UI dependent and relies on the SELECTED_FILE_CHANGED_PROPERTY property change event. What seems to happen is that it’s ignoring a null reference when it comes to changing (in particular) the selected file text field.

I tested this using Metal and Windows look and feel