java - 为什么 SwingWorker 不向 EDT 返回对象？

Question

我正在使用 SwingWorker 类来执行后台任务。在后台线程完成工作后，GUI 的许多不同组件都会更新(这些组件在 done() 方法中)。 doInBackground() 方法发布一个 HeatMap 类对象，process() 方法将其添加到 JPanel 组件。我已将 MouseListener 和 MouseMotionListener 添加到此 Heatmap 类对象中。 mouseMoved() 方法存在于主 GUI 类中。当鼠标移动时，鼠标在 HeatMap 上的坐标位置应显示在 JLabel 中。

当我运行代码时，HeatMap 对象在 JPanel 中可见，但我认为 EDT 无法访问它。这是因为，经过快速检查，我发现 rawIntensityMap HeatMap 对象在 process() 中不是 null SwingWorker 的方法，但在 mouseMoved() 方法中它仍然是 null，因此我得到一个 NullPointerException.

GUIMain 类和 SwingWorker 类中的 HeatMap 对象已声明为:

private HeatMap rawIntensityMap = null;

我不会将 rawIntensityMap 对象发送到 SwingWorker 类构造函数。我之前曾尝试过，但没有成功。

这是 SwingWorker 类中的 process() 方法:

 @Override
protected void process(List<HeatMap> chunks) {

    SwingUtilities.invokeLater(new Runnable() {
        @Override
        public void run() {
            imagePanel.add(rawIntensityMap, BorderLayout.CENTER);
            coordinates.setBounds(31, 31, rawIntensityMap.getWidth() - 31, rawIntensityMap.getHeight() - 31);
        }
    });

    }

这是mouseMoved()方法:

@Override
    public void mouseMoved(MouseEvent e) {
        System.out.println("I am in the mouseevent" + coordinates.toString());
        System.out.println("Width of raw Intensity map: " + rawIntensityMap.getWidth());
        if (e.getPoint().x >= 31 && e.getPoint().y >= 31 && e.getPoint().x <= rawIntensityMap.getWidth() - 31 && e.getPoint().y <= rawIntensityMap.getHeight() - 31) {
            rawIntensityMap.removeAll();
            rawIntensityMap.add(coordinates);
            coordinates.setText("(x,y) = " + "(" + (e.getPoint().x - 31) + "," + (e.getPoint().y - 31) + ")");
            if (peakPickedImage.isSelected()) {
                preprocessedIntensityMap.add(coordinates);
                coordinates.setText("(x,y) = " + "(" + (e.getPoint().x - 31) + "," + (e.getPoint().y - 31) + ")");
                coordinates.revalidate();
                coordinates.repaint();
            }
            coordinates.revalidate();
            coordinates.repaint();
        }
    }

这是我的 SwingWorker 类的基本结构:

public class FileReadWorker extends SwingWorker<REXP, HeatMap> {

 public FileReadWorker(GUIMain guiClassObject, File fileName, JTree rawSpectraTree, DefaultTreeModel model, DefaultMutableTreeNode root, String currentPath, JTextField minMz, JTextField maxMz, JFreeChart spectrumPlot, ChartPanel chartPanel, JPanel chartContent, float minMzValue, float maxMzValue, Float globalMinMz, Float globalMaxMz, JLabel statusLabel, JPanel imagePanel, JLabel coordinates, JTabbedPane tabbedSpectralFiles, JScrollPane spectralFilesScrollPane, JPanel rawFilesPanel, JRadioButton rawImage, JRadioButton peakPickedImage, JMenuItem loadPeakListMenuItem, JButton loadPeaklistsButton, JMenuItem propertiesMenuItem, JButton propertiesButton) {
        this.guiClassObject = guiClassObject;
        this.fileName = fileName;
        this.rawSpectraTree = rawSpectraTree;
        this.currentPath = currentPath;
        this.minMz = minMz;
        this.maxMz = maxMz;
        this.spectrumPlot = spectrumPlot;
        this.chartPanel = chartPanel;
        this.chartContent = chartContent;
        this.minMzValue = minMzValue;
        this.maxMzValue = maxMzValue;
        this.GlobalMinMz = globalMinMz;
        this.GlobalMaxMz = globalMaxMz;
        this.statusLabel = statusLabel;
        this.imagePanel = imagePanel;
        this.coordinates = coordinates;
        this.tabbedSpectralFiles = tabbedSpectralFiles;
        this.spectralFilesScrollPane = spectralFilesScrollPane;
        this.rawFilesPanel = rawFilesPanel;
        this.rawImage = rawImage;
        this.peakPickedImage = peakPickedImage;
        this.loadPeakListMenuItem = loadPeakListMenuItem;
        this.loadPeaklistsButton = loadPeaklistsButton;
        this.propertiesMenuItem = propertiesMenuItem;
        this.propertiesButton = propertiesButton;
        this.model = model;
        this.root = root;
    }

@Override
    protected REXP doInBackground() throws Exception {

// does some background tasks

// Works on the generating the HeatMap

try {
            rawIntensityMap = gim.generateIntensityMap(rawSpectrumObjects, currentPath, minMzValue, maxMzValue, Gradient.GRADIENT_Rainbow, "RAW");
            publish(rawIntensityMap);
        } catch (RserveException e) {
            e.printStackTrace();
        } catch (REXPMismatchException e) {
            e.printStackTrace();
        }

// returns a REXP object
        return rawSpectrumObjects;
    }

  @Override
    public void done() {

// Updates different components of the GUI
rawIntensityMap.addMouseListener(guiClassObject);
        rawIntensityMap.addMouseMotionListener(guiClassObject);
}


}

}

有人可以指出这里的错误吗？

更多代码:

这是我的 GUIMain 类，其中声明了 HeatMap rawIntensityMap。另外，我还粘贴了实际使用此 HeatMap 对象的部分代码(未粘贴所有方法)。

    public class GUIMain extends JFrame implements ActionListener, ItemListener, MouseListener, MouseMotionListener, ChangeListener {

    volatile HeatMap rawIntensityMap;
private JPanel imagePanel; // container for the HeatMap


 /**
     * Constructor to setup the GUI
     */
    public GUIMain(String title) {

        super(title);

        setLayout(new BorderLayout());
        //getSize();
        setSize(getSize());

 imagePanel = new JPanel(new BorderLayout());
        g.gridx = 0;
        g.gridy = 1;
        g.gridwidth = 2;
        g.weightx = 1.0; // fill the rest of the space
        g.weighty = 1.0;
        g.fill = GridBagConstraints.BOTH;

        imagePanel.setBorder(BorderFactory.createEtchedBorder());
        //imagePanel.addMouseListener(this);

        imageDisplay.add(imagePanel, g);
        //  ImageDisplay.setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));

        imageDisplay.setBorder(
                BorderFactory.createCompoundBorder(
                        BorderFactory.createTitledBorder("View 2-D ion intensity map"),
                        BorderFactory.createEmptyBorder(5, 5, 5, 5)));

}

public void actionPerformed(ActionEvent e) {

        //Handle open *.img imaging file button and menu item action

        if ((e.getSource() == OpenImagingFileButton) || (e.getSource() == loadRawSpectraMenuItem)) {
            int returnVal = fcImg.showOpenDialog(GUIMain.this);

            if (returnVal == JFileChooser.APPROVE_OPTION) {
                file = fcImg.getSelectedFile();

                root = new DefaultMutableTreeNode(file);
                rawSpectraTree = new JTree(root);
                model = (DefaultTreeModel) rawSpectraTree.getModel();

    //Passing this HeatMap to the SwingWorker class

    FileReadWorker frw = new FileReadWorker(this, file, rawSpectraTree, rawIntensityMap, model, root, currentPath, minMz, maxMz, spectrumPlot, chartPanel, chartContent, minMzValue, maxMzValue, GlobalMinMz, GlobalMaxMz, statusLabel, imagePanel, coordinates, tabbedSpectralFiles, spectralFilesScrollPane, rawFilesPanel, rawImage, peakPickedImage, loadPeakListMenuItem, loadPeaklistsButton, propertiesMenuItem, propertiesButton);
                    frw.execute();

}


    // Method when a different HeatMap color gradient is selected
    @Override
        public void itemStateChanged(ItemEvent e) {
            colorNumber = (Integer) e.getItem();
            if (e.getStateChange() == ItemEvent.SELECTED) {
                rawIntensityMap.updateGradient(gradients[colorNumber]);
                if (peakPickedImage.isEnabled()) {
                    preprocessedIntensityMap.updateGradient(gradients[colorNumber]);
                }
            }

        }

    // Mouse moved event

     @Override
        public void mouseMoved(MouseEvent e) {
            if(rawIntensityMap == null)
                System.out.println("TRUE**");
            else
                System.out.println("FALSE**");
            System.out.println("I am in the mouseevent" + coordinates.toString());
            if (e.getPoint().x >= 31 && e.getPoint().y >= 31 && e.getPoint().x <= rawIntensityMap.getWidth() - 31 && e.getPoint().y <= rawIntensityMap.getHeight() - 31) {
                rawIntensityMap.removeAll();
                rawIntensityMap.add(coordinates);
                coordinates.setText("(x,y) = " + "(" + (e.getPoint().x - 31) + "," + (e.getPoint().y - 31) + ")");
                if (peakPickedImage.isSelected()) {
                    preprocessedIntensityMap.add(coordinates);
                    coordinates.setText("(x,y) = " + "(" + (e.getPoint().x - 31) + "," + (e.getPoint().y - 31) + ")");
                    coordinates.revalidate();
                    coordinates.repaint();
                }
                coordinates.revalidate();
                coordinates.repaint();
            }
        }

    }

SwingWorker 类中的代码已粘贴在上面。

Answer 1

您有两个完全独立的字段，名为 rawIntensityMap。

您有GUIMain.rawIntensityMap和FileReadWorker.rawIntensityMap。您在 FileReadWorker::doInBackground 中分配 FileReadWorker.rawIntensityMap，但从未将 GUIMain.rawIntensityMap 分配给任何值。

尝试在 GUIMain 中为 rawIntensityMap 创建 setter，并在 FileReadWorker::done< 中调用 guiClassObject.setRawIntensityMap(rawIntensityMap);/.