我的 JProgressBar 直到 100% 才更新 [英] My JProgressBar is not Updating Until it is 100%

问题描述

好的，我有以下代码.

public class MyProgressBar extends JPanel implements MyData, Serializable {

    /**
     * 
     */

    public static final int MAX                = 10000;
    public static final int WIDTH              = 400;
    public static final int HEIGHT             = 75;

    private JProgressBar    MyBar              = new JProgressBar( SwingConstants.HORIZONTAL, 0, MAX );
    private JFrame          MyFrame            = new JFrame();

    private int             MyValue            = 0;

    private Thread          MyThread           = new Thread( new ProgressThread() );



    public MyProgressBar() {
        add(MyBar);

        int x = ( MyData.SCREEN.width  / 2 ) - ( WIDTH  / 2);
        int y = ( MyData.SCREEN.height / 2 ) - ( HEIGHT / 2);

        this.setBounds( x, y, WIDTH, HEIGHT );

        MyFrame.setBounds( x, y, WIDTH, HEIGHT );
        MyFrame.setUndecorated(true);
        MyFrame.getContentPane().setSize( new Dimension( WIDTH, HEIGHT ) );
        MyFrame.setMinimumSize( new Dimension( WIDTH, HEIGHT ) );
        MyFrame.setPreferredSize( new Dimension( WIDTH, HEIGHT ) );
        MyFrame.setSize( new Dimension( WIDTH, HEIGHT ) );
        MyFrame.setVisible(false);
        MyFrame.getContentPane().setLayout(null);

        MyBar.setStringPainted( true );
        MyBar.setBorderPainted( true );
        MyBar.setValue( 0 );
        MyBar.setBounds( 0, 0, WIDTH, HEIGHT );

        MyFrame.add( MyBar );
        MyFrame.pack();
        MyFrame.repaint();

    }

    public void MyUpdateBar() {
        MyBar.setValue( MyValue );
        MyBar.repaint();
        MyFrame.repaint();
        this.repaint();
        //dbug.Message( "MYPROGRESSBAR", "MyUpdateBar", "Value is %3.2f %d", MyBar.getPercentComplete(), MyValue );
    }

    public void MySetValue( int percent ) {
        MyValue = (int)( MAX * ( (double)percent / 100.0 ) );
        MyUpdateBar();
        //dbug.Message( "MYPROGRESSBAR", "MySetValue", "Value is %3.2f %d percent was %d", MyBar.getPercentComplete(), MyValue, percent );
    }

    public void CreateAndShow () {
        MyFrame.setVisible(true);
        MyThread.start();
    }

    public void HideAndClear () {
        MyThread.stop();
        //frame.setVisible(false);
    }

    class ProgressThread implements Runnable {
        public void run() {
            EventQueue.invokeLater(new Runnable() {
                public void run() {
                    while( MyValue < MyBar.getMaximum() ) {
                        MyBar.setValue( MyValue );
                        MyBar.repaint();
                        MyFrame.repaint();
                        dbug.Message( "MYPROGRESSBAR", "THREAD", "Value is %3.2f %d", MyBar.getPercentComplete(), MyValue );
                    }
                }
            });
        }

    }



}

如您所见，我创建了一个类来显示进度.发生的事情是我实例化了这个类.加载我的 XML 文件，然后当我解析数据时，我正在调用更新 MyValue，当我让我的 dbug 消息出来时，我会看到它.但是，直到 100% 完成，条形图本身才会显示.我已经阅读了有关线程和遵循其他人的示例的内容，如果我将其作为他的示例，它会起作用.如果我进行了一些调整(更改线程中的循环以填充进度条的设置值以读取值)，它甚至不会显示到 100.

As you can see, I have created a class that I want to have show the progress. What happens is I instantiate the class. Load my XML file, then as I am parsing data, I am calling to update the MyValue which I see when I let my dbug messages come out. However, the bar itself does not even show until it is 100% complete. I have read about threading and following someone else's example and if I left it as his example it worked. If I made a few tweaks (changing a loop in the thread to populate the setvalue of the progress bar to read a value) it does not even show until it is 100.

我做错了什么?

谢谢！

推荐答案

您的线程执行 SwingUtilities.invokeLater.您有效地在 Swing 的事件调度线程上运行.不知道你想达到什么目的.但看起来您正在阻止 EDT 并且您的 while 循环未更新，因为 MySetValue 未执行.

You thread executes SwingUtilities.invokeLater. You're effectively running on Swing's Event Dispatch Thread. Not sure what are you trying to achieve. But it looks like you are blocking EDT and your while loop is not updated as MySetValue is not executed.

考虑使用 SwingWorker 进行冗长的操作.如何使用进度条 演示了 SwingWorker 和 JProgressBar.

Consider using SwingWorker for lengthy operations. How to Use Progress Bars demonstrates use of SwingWorker with JProgressBar.

确保您从 Event Dispatch Thread 调用 setValue 方法.为此，您可以使用 SwingUtilities.invokeLater.阅读有关 线程和 Swing 的更多信息.

Make sure you call setValue method from the Event Dispatch Thread. You can use SwingUtilities.invokeLater for that. Read more about Threads and Swing.

考虑这个简化的示例:

public static void main(String[] arguments) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(EXIT_ON_CLOSE);

    final JProgressBar bar = new JProgressBar(0, 100);

    Thread t = new Thread(){
        public void run(){
            for(int i = 0 ; i < 100 ; i++){
                final int percent = i;
                SwingUtilities.invokeLater(new Runnable() {
                    public void run() {
                        bar.setValue(percent);
                    }
                  });

                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {}
            }
        }
    };
    frame.add(bar);
    frame.pack();
    frame.setVisible(true);
    t.start();
}

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