在处理时更新JProgressBar [英] updating a JProgressBar while processing

问题描述

我知道这个主题已经在许多问题上被看到并且已经得到了回答，但是，我仍然无法理解它。

I know the subject has already been seen on many Questions and has been answered, but still, I can't get trough it.

我只想在提取大型xml文件的某些内容时更新progressBar。
我认为在不同的线程中使用耗时的循环已足够了但是？..
我设法获得的是progressBar要么根本没有显示，要么在最后更新，就在之前它关闭了。

I just want to update a progressBar while extracting some stuff of a large xml file. I thought it was enough to have the time-consuming loop in a different thread but ?.. All I managed to get is the progressBar either not showed at all, or updated at the end, just before it's closed.

在应用程序启动附近的某个地方，我有：

Instanced somewhere near the launch of the application, I have:

public class SomeClass {
    private SomeClass () {
        myXMLParser reader = new myXMLParser();
        CoolStuff fromXml = reader.readTheXml();
    }
}

在显示和更新带有JProgressBar的JDialog时：

while showing and updating a JDialog with a JProgressBar:

public class LoadingDialog extends JDialog {
    private JProgressBar progressBar;
    /* ... */
    public void progress() {
        progressBar.setValue(progressBar.getValue() + 1);
    }
}

所以我有这个 myXMLParser ：

public class myXMLParser {
    private LoadingDialog loadingDialog = new LoadingDialog();

    public CoolStuff readTheXml() {
        CoolStuff fromXml = new CoolStuff();
        while(manyIterations) {
            loadingDialog.progress();
            fromXml.add(some() + xml() + reading());
        }
        return fromXml;
    }
}

我见过许多 SwingWorker 并使用 PropertyChange 事件更新progressBar，但示例总是给出 all-in-one ，其中处理和同一类中的进度条，以及类中的类，并且从Java开始，我无法将其转换为我的情况。

I have seen many things with SwingWorker and using PropertyChange events update the progressBar, but examples are always given all-in-one, with the processing and the progressbar within the same class, and with classes within classes, and since I begin in Java, I wasn't able to translate that to my situation.

任何帮助？..任何（不太明显）的建议？

Any help ?.. Any (not too obvious) advices ?

编辑：所以感谢btantlinger它的工作原理如下：

So thanks to btantlinger it worked like that:

public class SomeClass {
    private SomeClass () {
        myXMLParser reader = new myXMLParser();
        new Thread(new Runnable() {
            @Override
            public void run() {
                CoolStuff fromXml = reader.readTheXml();
            }
        }).start();
    }
}

public class LoadingDialog extends JDialog {
    private JProgressBar progressBar;
    /* ... */
    public void progress() {
        progressBar.setValue(progressBar.getValue() + 1);
    }
}

public class myXMLParser {
    private LoadingDialog loadingDialog = new LoadingDialog();

    public CoolStuff readTheXml() {
        CoolStuff fromXml = new CoolStuff();
        while(manyIterations) {
            SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                    loadingDialog.progress();
                }
            });
            fromXml.add(some() + xml() + reading());
        }
        return fromXml;
    }
}

推荐答案

你必须更新Swing Event Dispatch Thread上的JProgress栏。你无法在任何其他线程上修改Swing组件。

You MUST update the JProgress bar on the Swing Event Dispatch Thread. You cannot modify Swing components on any other thread.

你唯一的另一种选择是在开始你的线程之前将JProgress栏设置为indeterminate，其中进度条将只是来回走动。

Your only other alternative would be to set the JProgress bar "indeterminate" before you start your thread where the progress bar will just go back and forth.

例如

progBar.setIndeterminate(true);

参见SwingWorker javadoc：
http://docs.oracle.com/javase/6/docs/api/javax/swing/SwingWorker.html

See the SwingWorker javadoc: http://docs.oracle.com/javase/6/docs/api/javax/swing/SwingWorker.html

如果您不想使用SwingWorker，另一个选项是 SwingUtilities.invokeLater 方法

If you don't want to use the SwingWorker, another option is the SwingUtilities.invokeLater method

//inside your long running thread when you want to update a Swing component
SwingUtilities.invokeLater(new Runnable() {
    public void run() {

        //This will be called on the EDT
        progressBar.setValue(progressBar.getValue() + 1);


    }
});

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