コード例 #1
0
  /**
   * Create preview component.
   *
   * @param comboBox the options.
   * @return the component.
   */
  private static Component createPreview(final JComboBox comboBox) {
    final JComponent preview;

    JLabel noPreview =
        new JLabel(GuiActivator.getResources().getI18NString("impl.media.configform.NO_PREVIEW"));
    noPreview.setHorizontalAlignment(SwingConstants.CENTER);
    noPreview.setVerticalAlignment(SwingConstants.CENTER);

    preview = createVideoContainer(noPreview);

    preview.setPreferredSize(new Dimension(WIDTH, 280));
    preview.setMaximumSize(new Dimension(WIDTH, 280));

    final ActionListener comboBoxListener =
        new ActionListener() {
          public void actionPerformed(ActionEvent event) {
            MediaDevice device = (MediaDevice) comboBox.getSelectedItem();

            if ((device != null) && device.equals(videoDeviceInPreview)) return;

            Exception exception;
            try {
              createPreview(device, preview);
              exception = null;
            } catch (IOException ex) {
              exception = ex;
            } catch (MediaException ex) {
              exception = ex;
            }
            if (exception != null) {
              logger.error("Failed to create preview for device " + device, exception);

              device = null;
            }

            videoDeviceInPreview = device;
          }
        };
    comboBox.addActionListener(comboBoxListener);

    /*
     * We have to initialize the controls to reflect the configuration
     * at the time of creating this instance. Additionally, because the
     * video preview will stop when it and its associated controls
     * become unnecessary, we have to restart it when the mentioned
     * controls become necessary again. We'll address the two goals
     * described by pretending there's a selection in the video combo
     * box when the combo box in question becomes displayable.
     */
    comboBox.addHierarchyListener(
        new HierarchyListener() {
          public void hierarchyChanged(HierarchyEvent event) {
            if (((event.getChangeFlags() & HierarchyEvent.DISPLAYABILITY_CHANGED) != 0)
                && comboBox.isDisplayable()) {
              // let current changes end their execution
              // and after that trigger action on combobox
              SwingUtilities.invokeLater(
                  new Runnable() {
                    public void run() {
                      comboBoxListener.actionPerformed(null);
                    }
                  });
            } else {
              if (!comboBox.isDisplayable()) videoDeviceInPreview = null;
            }
          }
        });

    return preview;
  }