Java SwingWorker 挂起

Question

我正在调试一些使用 SwingWorker 编写的代码，以执行数值计算和 GUI 更新的组合。 SwingWorker 挂起并显示以下堆栈跟踪：

Full thread dump Java HotSpot(TM) Client VM (14.3-b01 mixed mode, sharing):

"SwingWorker-pool-3-thread-4" prio=6 tid=0x07fd7c00 nid=0x143c waiting on condition [0x0a33f000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
        at java.lang.Thread.sleep(Native Method)
        at sum.ee.ui.modelviewer.ModelViewer$ModelAnimator.doInBackground(ModelViewer.java:940)
        at sum.ee.ui.modelviewer.ModelViewer$ModelAnimator.doInBackground(ModelViewer.java:877)
        at javax.swing.SwingWorker$1.call(SwingWorker.java:274)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        at javax.swing.SwingWorker.run(SwingWorker.java:313)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:619)

"SwingWorker-pool-3-thread-3" prio=6 tid=0x07fd7000 nid=0x11a8 waiting for monitor entry [0x0a2af000]
   java.lang.Thread.State: BLOCKED (on object monitor)
        at java.awt.Component.resize(Component.java:2044)
        - waiting to lock <0x24b936a0> (a java.awt.Component$AWTTreeLock)
        at java.awt.Component.setSize(Component.java:2035)
        at java.awt.Component.resize(Component.java:2069)
        at java.awt.Component.setSize(Component.java:2060)
        at javax.swing.JViewport.setViewSize(JViewport.java:1038)
        at javax.swing.ViewportLayout.layoutContainer(ViewportLayout.java:183)
        at java.awt.Container.layout(Container.java:1421)
        at java.awt.Container.doLayout(Container.java:1410)
        at jsyntaxpane.components.LineNumbersRuler.updateSize(LineNumbersRuler.java:109)
        at jsyntaxpane.components.LineNumbersRuler.removeUpdate(LineNumbersRuler.java:203)
        at javax.swing.text.AbstractDocument.fireRemoveUpdate(AbstractDocument.java:243)
        at jsyntaxpane.SyntaxDocument.fireRemoveUpdate(SyntaxDocument.java:118)
        at javax.swing.text.AbstractDocument.handleRemove(AbstractDocument.java:608)
        at javax.swing.text.AbstractDocument.remove(AbstractDocument.java:576)
        at javax.swing.JEditorPane.setText(JEditorPane.java:1493)
        at sum.ee.ui.SourceCodePanel.clearSourcePane(SourceCodePanel.java:256)
        at sum.ee.ui.SourceCodePanel.access$100(SourceCodePanel.java:47)
        at sum.ee.ui.SourceCodePanel$1.stateChanged(SourceCodePanel.java:209)
        at sum.ee.ui.VisualizationAggregator.fireStateChanged(VisualizationAggregator.java:300)
        at sum.ee.ui.VisualizationAggregator.update(VisualizationAggregator.java:97)
        at sum.ee.ui.modelviewer.ModelViewer$ModelAnimator.doInBackground(ModelViewer.java:918)
        at sum.ee.ui.modelviewer.ModelViewer$ModelAnimator.doInBackground(ModelViewer.java:877)
        at javax.swing.SwingWorker$1.call(SwingWorker.java:274)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        at javax.swing.SwingWorker.run(SwingWorker.java:313)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor

$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:619)

我的理解是 GUI 工作不应该在 doInBackground() 内部完成，而应该在 done() 中完成>。我进行了一个幼稚的实验，将 doInBackground() 中的所有代码移至 done() 中，但它仍然不起作用。人们可以给我一些建议，告诉我如何从根本上解决这个问题吗？代码如下所示：

protected Void doInBackground() {
    isAnimating = true;
    resetButtonBackgrounds();
    backgroundColor = new Color(175, 255, 175);  // Soft Green

    JToggleButton b = null;
    for (final int index : modelIndices) {
        if (index == modelIndices.get(modelIndices.size() - 1)) {
            backgroundColor = defaultBackgroundColor;
        }
        if (!keepTrace) {
            // Resetting the backgrounds is necessary to have
            // individual display of the changing elements due to
            // the fact that there can be multiple nodes per
            // source line.  The reset works in combination
            // with updating from ModelViewer.this (as opposed
            // to the 'this' of ModelAnimator instances) due
            // to not sending an event to itself.  Furthermore,
            // if the event was sent from ModelAnimator, the model
            // indices are recalculated, causing a jump when multiple
            // element source lines are encountered.
            resetButtonBackgrounds();
        }
        aggregator.modelIndex(index);
        aggregator.update(ModelViewer.this);

        b = getButtonByIndex(index);
        scrollRectToVisible(b.getBounds());
        ModelViewer.this.repaint();
        try {
            StaticTools.sleepAtLeast(sleepTimeMilliseconds);
        } catch (final InterruptedException ex) {
            // continue with thread
        }
    }

    isAnimating = false;
    
    if ( b != null) {

        Color orig = b.getBackground();
        Color blink = Color.PINK;
        Color current = orig;
        for (int i = 0; i < 100; i++) {

            try {
                Thread.sleep(100);
            } catch (InterruptedException ex) {
            }

            if (current == orig) {
                current = blink;
            } else {
                current = orig;
            }

            b.setBackground(current);
            ModelViewer.this.repaint();

        }
    }

    return null;
}

另一个线索是有两个 SwingWorker 线程在执行。他们可以运行同一个线程吗？

更新：以下是执行SwingWorker的代码：

public final void animate(final long delayBetweenUpdatesMilliseconds,
    final List<Integer> modelIndices,
    final boolean keepTrace,
    final List<PropertyChangeListener> propertyChangeListeners) {

    ModelAnimator modelAnimator =
        new ModelAnimator(
            delayBetweenUpdatesMilliseconds, 
            modelIndices,
            keepTrace);
    for (final PropertyChangeListener listener : propertyChangeListeners) {
        modelAnimator.addPropertyChangeListener(listener);
    }

    modelAnimator.execute();
}

Answer 1

这是对 Swing EDT 规则的不遵守。

SwingWorker 的目的是在发生 UI 事件时执行繁重的非 GUI 任务，否则会阻塞 UI，然后在最后更新 UI。

所以你可以在 doInBackground(); 中实现举重。然后，一旦完成 swing，就会在 EDT 上调用 done()，并且您可以使用 get() 检索结果。

这里的问题是您正在 SwingWorker 创建的新线程中执行 GUI 工作。这可能会导致死锁和并发问题。

这包括创建所述 GUI 对象，即使您已经在 EDT

操作中，这些对象也应该位于可运行对象中，例如：

b = getButtonByIndex(index);

应该使用 InvokeandWait 封装在可运行对象中。实际修改 GUI 本身的东西尤其需要在它们自己的可运行对象中，即使如果您已经在响应按钮按下或更改的 swing 事件调度线程中，您也会冒着处理您的对象的风险。已经在工作了。

例如，swing 正在工作并锁定 A 以让您工作，让您在 B 上工作尝试锁定并在 A 上工作