Question

我有我的主GUI线程，其中包含JprogressBar并正在实现ProprtyChangeListener。

当按下某个按钮时，另一个扩展SwingWorker的类会启动并执行一系列可能很长的计算。我需要A类中的进度条根据B类中的变量显示进度。

我的代码在下面（对于我所有失败的尝试都可能有点混乱......）

感谢任何帮助。

GUI CLASS：

SignalSimulator signalSimulator = new SignalSimulator(
                path, numOfdataPoints, numOfLocalSpikes,
                    numOfExpSpikes, noiseAmp, slope, offset,
                                    rdbtnSineWave.isSelected());       
signalSimulator.addPropertyChangeListener( new PropertyChangeListener() {
    public void propertyChange(PropertyChangeEvent evt) {
        String property = evt.getPropertyName();
        if ("progress".equals(property)) {
            int progress = (Integer) evt.getNewValue();
            System.out.println("value in PropertChangeListener is: " + progress);
            progressBar.setValue(progress);
        }
    }
});
signalSimulator.execute();

计算类：

protected Integer doInBackground() throws Exception {
    if (isSine){
        data = generateSineWave(numOfDataPoints, noiseAmp, offset);
        data = addAnomalies(data, numOfPointOutliers, numOfExpSpikes);
    } else {
        data = generateLinearSignal(numOfDataPoints, noiseAmp, slope, offset);
        data = addAnomalies(data, numOfPointOutliers, numOfExpSpikes);
    }
    writeLogFile(path, ".txt", data);
    firePropertyChange("progress", 1, 1);
    setProgress((int)progress);
    publish(progress);
    System.out.println("value in doInBackground is: " + progress);
    return 1;
}

修改

原始问题仍然存在。由于某种原因，进度条仍未更新，我确信progressBar.setValue（progress）中的“progress”变量正在更新，但GUI中的进度条保持不变（固定为0）这是我的新代码：

GUI类：

    SignalSimulator signalSimulator = new SignalSimulator(path, numOfdataPoints, numOfLocalSpikes, numOfExpSpikes, noiseAmp, slope, offset, rdbtnSineWave.isSelected());       
    signalSimulator.addPropertyChangeListener( new PropertyChangeListener() {
      public void propertyChange(PropertyChangeEvent evt) {
        String property = evt.getPropertyName();

        if ("progress".equals(property)) {
            int progress = (Integer) evt.getNewValue();
             System.out.println("value in PropertChangeListener is: " + progress);
             progressBar.setValue(progress);

        }
      }
    });
    signalSimulator.execute();

SwingWorker类：

@Override
        protected Integer doInBackground() throws Exception {

            if (isSine){
                data = generateSineWave(numOfDataPoints, noiseAmp, offset);
                data = addAnomalies(data, numOfPointOutliers, numOfExpSpikes);
            }
            else{
                data = generateLinearSignal(numOfDataPoints, noiseAmp, slope, offset);
                data = addAnomalies(data, numOfPointOutliers, numOfExpSpikes);
            }

            writeLogFile(path, ".txt", data);

            return 1;}


public double[] generateSineWave(int numOfDataPoints, double noiseAmp, double offset){

            Random rnd = new Random();
            double[] dataArray = new double[numOfDataPoints];           


            for (int i=0;i<numOfDataPoints;i++){

                dataArray[i] =  Math.sin(Math.toRadians(i))+rnd.nextDouble()*noiseAmp+offset;
                progress = ((double)i)/(double)numOfDataPoints*100;

                //firePropertyChange("progress", 1, 1);
                setProgress((int)progress);
                //publish(progress);
                System.out.println("value in doInBackground is: " + progress);
            }

            return dataArray;

修改没有额外的（不相关的）代码重写了整个事情。我想我错过了一些基本的东西因为它仍然没有更新进度条。

public class ProgressBarTest implements PropertyChangeListener {


    private JFrame frame;
    private JButton btnRun;
    static JProgressBar progressBar = new JProgressBar(0,100);

public static void main(String[] args) {

        EventQueue.invokeLater(new Runnable()  {
            public void run() {
                try {
                    //UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel"); 
                    UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); 
                    ProgressBarTest window = new ProgressBarTest();
                    window.frame.setVisible(true);
                    //SignalSimulator signalSimulator = new SignalSimulator();

                } catch (Exception e) {
                    e.printStackTrace();
                }

            }
        });
    }

/**
 * Create the application.
 */
public ProgressBarTest() {
    initialize();
}

private void initialize() {
    frame = new JFrame();
    frame.setBounds(100, 100, 450, 300);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().setLayout(null);
    frame.setResizable(false);  

    JProgressBar progressBar = new JProgressBar();
    progressBar.setAlignmentX(Component.RIGHT_ALIGNMENT);
    progressBar.setBounds(0, 252, 444, 20);
    progressBar.setStringPainted(true);
    frame.getContentPane().add(progressBar);


    JButton btnRun = new JButton("Start Long Run");
    btnRun.setBounds(167, 214, 159, 31);
    frame.getContentPane().add(btnRun);
    btnRun.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            // TODO Auto-generated method stub
            longRun();
        }

    } );

}


private void longRun(){

    LongRunner longRunner = new LongRunner(100000);
    longRunner.addPropertyChangeListener(new PropertyChangeListener() {

        @Override
        public void propertyChange(PropertyChangeEvent evt) {

            if ("progress".equals(evt.getPropertyName())){
                int progress = (int) evt.getNewValue();
                System.out.println("Value in propertyChangeListener: "+progress);
                progressBar.setValue(progress);
            }
        }
    });
    longRunner.execute();
}
@Override
public void propertyChange(PropertyChangeEvent arg0) {
    // TODO Auto-generated method stub

}

}

和SwingWorker：

import javax.swing.SwingWorker;


public class LongRunner extends SwingWorker<Integer, Double>{

    int numOfPoints;
    double progress;

    public LongRunner(int numOfPoints) {

        this.numOfPoints = numOfPoints;
        this.progress = 0;
    }

    private void runLong(int bigNum){

        for (int i=0; i< bigNum; i++){

            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            progress =  (((double)i*100)/(double)bigNum);
            setProgress((int)progress);
            System.out.println("Value in setProgress: "+progress);

        }

    }
    @Override
    protected Integer doInBackground() throws Exception {

        runLong(numOfPoints);
        return null;
    }

}

我在这里做错了什么？

Answer 1

您直接从代码中调用doInBackground()，这类似于直接在runnable中调用run()。这意味着您的代码实际上并不在后台线程上运行，因此您可能会使用长时间运行的代码来破坏事件线程，从而阻止Swing GUI和进度条进行更新。

解决方案：不要这样做。如果希望它运行，请致电execute()。

如果您需要进一步的帮助，您首先需要帮助我们。您了解到您发布了大量代码，其中大部分代码与您手头的问题完全无关，而且肯定会超过您应该让志愿者通过的代码。请删除所有无关的无关代码，而是创建并发布适当的MCVE。

修改
您似乎也直接从EDT调用代码，这些代码应保留在您的工作线程中：

signalSimulator.execute(); // ************* all these signalSimulator calls below *********** if (rdbtnSineWave.isSelected()) { data = signalSimulator.generateSineWave(numOfdataPoints, noiseAmp, offset); data = signalSimulator.addAnomalies(data, numOfLocalSpikes, numOfExpSpikes); } else { // Linear signal is selected data = signalSimulator.generateLinearSignal(numOfdataPoints, noiseAmp, slope, offset); data = signalSimulator.addAnomalies(data, numOfLocalSpikes, numOfExpSpikes); } signalSimulator.writeLogFile(path, ".txt", data);

您似乎也只创建一个工作线程对象，因为您无法重复使用SwingWorker对象，因此该对象不正确。

我建议您只在需要时创建SwingWorker对象，将所需信号类型的信息传递给构造函数。这样，可以从SwingWorker的doInBackground方法调用上述方法。

如，

signalSimulator = SignalSimulator(rdbtnSineWave.isSelected()) signalSimulator.addPropertyChangeListener(...); signalSimulator.execute();

请注意，您在发布的代码中还有其他一些重要的无关问题，但是必须在其他时间解决它们，但它们包括使用null布局和setBounds，几乎总是一个非常糟糕的主意。< / p>

修改

再次澄清一下，你的主要问题是你在Swing事件线程上调用长时间运行的代码。仅仅因为一个方法位于您的Worker类中并不意味着调用它会自动让它在后台线程上运行。保证这一点的唯一方法是在doInBackground()方法中调用代码。同样，您要做的是在需要时创建新的工作对象，例如，在某个ActionListener内部，并在创建时将所有信息传递给它将需要运行。然后添加PropertyChangeListener，然后添加.execute()您的工作人员。这样做，我敢打赌你的代码会更好。

修改
例如

import java.awt.event.*; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.util.Random; import java.util.concurrent.ExecutionException; import javax.swing.*; public class ProgressExampleGui { private JPanel mainPanel = new JPanel(); private JProgressBar progressBar = new JProgressBar(); private JButton pressMeBtn = new JButton(new MyAction("Press Me", KeyEvent.VK_P, this)); public ProgressExampleGui() { progressBar.setStringPainted(true); progressBar.setString(""); mainPanel.add(pressMeBtn); mainPanel.add(progressBar); } public void setProgress(int progress) { progressBar.setValue(progress); progressBar.setString(progress + "%"); } public JComponent getMainComponent() { return mainPanel; } public void setEnabled(boolean enabled) { pressMeBtn.setEnabled(enabled); } private static void createAndShowGui() { ProgressExampleGui progExampleGui = new ProgressExampleGui(); JFrame frame = new JFrame("Progress Example"); frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); frame.getContentPane().add(progExampleGui.getMainComponent()); frame.pack(); frame.setLocationByPlatform(true); frame.setVisible(true); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { createAndShowGui(); } }); } } @SuppressWarnings("serial") class MyAction extends AbstractAction { private ProgressExampleGui gui; public MyAction(String name, int mnemonic, ProgressExampleGui gui) { super(name); putValue(MNEMONIC_KEY, mnemonic); this.gui = gui; } @Override public void actionPerformed(ActionEvent e) { AbstractButton source = (AbstractButton) e.getSource(); gui.setProgress(0); source.setEnabled(false); MyWorker myWorker = new MyWorker(); myWorker.addPropertyChangeListener(new WorkerPropChngListener(gui)); myWorker.execute(); } } class WorkerPropChngListener implements PropertyChangeListener { private ProgressExampleGui gui; public WorkerPropChngListener(ProgressExampleGui gui) { this.gui = gui; } @Override public void propertyChange(PropertyChangeEvent pcEvt) { MyWorker myWorker = (MyWorker) pcEvt.getSource(); if ("progress".equals(pcEvt.getPropertyName())) { int progress = ((Integer)pcEvt.getNewValue()).intValue(); gui.setProgress(progress); } if (SwingWorker.StateValue.DONE.equals(pcEvt.getNewValue())) { try { myWorker.get(); } catch (InterruptedException | ExecutionException e) { e.printStackTrace(); } gui.setEnabled(true); } } } class MyWorker extends SwingWorker<Void, Void> { private static final int MAX_INCR = 8; private static final long SLEEP_TIME = 200; private static final int MAX_VALUE = 100; private int value = 0; private Random random = new Random(); @Override protected Void doInBackground() throws Exception { while (value < MAX_VALUE) { value += random.nextInt(MAX_INCR); value = Math.min(value, MAX_VALUE); Thread.sleep(SLEEP_TIME); setProgress(value); } return null; } }

修改
关于您的新代码，您有两个主要问题：

查看数据输出的结果：

Value in setProgress: 0.0 Value in setProgress: 0.001 Value in setProgress: 0.002 Value in setProgress: 0.003 Value in setProgress: 0.004 Value in setProgress: 0.005 Value in setProgress: 0.006 Value in setProgress: 0.007 Value in setProgress: 0.008 Value in setProgress: 0.009 Value in setProgress: 0.01 Value in setProgress: 0.011 Value in setProgress: 0.012 Value in setProgress: 0.013 Value in setProgress: 0.014 Value in setProgress: 0.015 Value in setProgress: 0.016 Value in setProgress: 0.017 Value in setProgress: 0.018 Value in setProgress: 0.019 Value in setProgress: 0.02 Value in setProgress: 0.021 Value in setProgress: 0.022 Value in setProgress: 0.023 Value in setProgress: 0.024 Value in setProgress: 0.025 Value in setProgress: 0.026 Value in setProgress: 0.027 Value in setProgress: 0.028 Value in setProgress: 0.029

按照这样的速度，你的进度值将达到1，并在下一个冰河时代到来时对PropertyChangeListener和JProgressBar造成明显的变化。首先，改变你的睡眠时间，并将你的大号改为更合理的东西。

接下来，您将影响重要变量，尤其是JProgressBar变量progressBar。您可以在此处声明它并在类中初始化它：

public class ProgressBarTest implements PropertyChangeListener { private JFrame frame; private JButton btnRun; static JProgressBar progressBar = new JProgressBar(0, 100);

作为旁注，这个变量绝对不应该被声明为static，但这不是你当前问题的原因。原因是你实际上在initialize方法的其他地方重新声明相同的变量，然后将这个新对象添加到你的GUI中：

private void initialize() { frame = new JFrame(); // ..... JProgressBar progressBar = new JProgressBar(); // ..... frame.getContentPane().add(progressBar);

请理解这个新的progressBar变量引用了一个完全不同的JProgressBar，因此如果你提升在类中创建的对象的值，你的GUI将不会显示任何内容，因为它显示的是完全不同的对象。要解决此问题，**不要在initialize方法中重新声明并初始化新变量。而是使用在类中创建的对象。

您的代码的其他问题：您使用null布局和setBounds很多。这将向所有人表明你是一个新手Swing程序员，因为这意味着你喜欢创建极难升级的严格程序，并且在所有系统上可能看起来不太好。而是使用布局管理器。例如，这里是您的代码，其中包含一些更改，所有注释都标注：

import java.awt.*; import java.awt.event.*; import java.beans.*; import javax.swing.*; //!! no need to implement PropertyChangeListener //!! public class ProgressBarTest implements PropertyChangeListener { public class ProgressBarTest2 { private JFrame frame; private JButton btnRun; // !! this shouldn't be static! // !! static JProgressBar progressBar = new JProgressBar(0, 100); private JProgressBar progressBar = new JProgressBar(0, 100); // !! public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { try { UIManager .setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); ProgressBarTest2 window = new ProgressBarTest2(); window.frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } public ProgressBarTest2() { initialize(); } private void initialize() { frame = new JFrame(); // !!frame.setBounds(100, 100, 450, 300); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //!! frame.getContentPane().setLayout(null); //!! never use null layouts frame.setResizable(false); // !! don't create a shadowed variable // !! JProgressBar progressBar = new JProgressBar(); progressBar.setAlignmentX(Component.RIGHT_ALIGNMENT); //!! progressBar.setBounds(0, 252, 444, 20); progressBar.setStringPainted(true); //!! frame.getContentPane().add(progressBar); frame.getContentPane().add(progressBar, BorderLayout.SOUTH); btnRun = new JButton("Start Long Run"); //!! no shadowing //!! btnRun.setBounds(167, 214, 159, 31); JPanel panel = new JPanel(); //!! panel.setPreferredSize(new Dimension(450, 300)); //!! panel.setLayout(new GridBagLayout()); //!! panel.add(btnRun); //!! frame.getContentPane().add(panel, BorderLayout.CENTER); //!! btnRun.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { longRun(); } }); //!! frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } private void longRun() { //!! use a more realistic value, one that should show change in listener //!! LongRunner longRunner = new LongRunner(100000); LongRunner2 longRunner = new LongRunner2(10000); longRunner.addPropertyChangeListener(new PropertyChangeListener() { @Override public void propertyChange(PropertyChangeEvent evt) { if ("progress".equals(evt.getPropertyName())) { int progress = (int) evt.getNewValue(); System.out.println("Value in propertyChangeListener: " + progress); progressBar.setValue(progress); } } }); longRunner.execute(); } // !! @Override // !! not needed // public void propertyChange(PropertyChangeEvent evt) { // } } class LongRunner2 extends SwingWorker<Integer, Double> { private static final long SLEEP_TIME = 15; // !! int numOfPoints; double progress; public LongRunner2(int numOfPoints) { this.numOfPoints = numOfPoints; this.progress = 0; } private void runLong(int bigNum) { for (int i = 0; i < bigNum; i++) { try { // !! quicker turn-over so that our bigNum can change // in a realistic way // !! Thread.sleep(100); Thread.sleep(SLEEP_TIME);// !! } catch (InterruptedException e) { e.printStackTrace(); } progress = (((double) i * 100) / (double) bigNum); setProgress((int) progress); // !! System.out.println("Value in setProgress: " + progress); //!! This will slow us down } } @Override protected Integer doInBackground() throws Exception { runLong(numOfPoints); return null; } }

无法从SwingWorker类更新JProgressBar

1 个答案: