JavaFX令人困惑的Stacktrace

Question

我的JavaFx应用程序抛出一个异常，并没有指向我自己代码的一行。这是什么意思？

这令我感到困惑，因为我现在几次遇到它而无法重现。一旦处于启动状态，一旦处于空闲状态（最小化）并返回应用程序，一旦处于空闲状态（但仍显示在屏幕上）并返回应用程序。

完整代码太长，我可以发布在配置中运行的小片段。以及一些完整应用程序的链接，以便了解我想要制作的内容。

https://www.youtube.com/watch?v=Oev1IJZvAPw

https://github.com/JoostMeulenkamp/VPL

Snippet 1（计算将项目添加到列表末尾的节点的功能）：

@Override
public void calculate() {

    //Get incoming data
    Object raw = inPorts.get(0).getData();
    Object item = inPorts.get(1).getData();

    //Finish calculate if there is no incoming data
    if (raw == null) {
        return;
    }

    //Check if all incoming data is in the correct format
    boolean hasError = false;
    if (!(raw instanceof List)) {
        System.out.println("This is not a list");
        hasError = true;
    }
    if (item instanceof List) {
        System.out.println("Just one item can be added at a time");
        hasError = true;
    }
    if (inPorts.get(1).connectedConnections.size() > 0
            && inPorts.get(0).connectedConnections.size() > 0) {
        Class listDataType = inPorts.get(0).connectedConnections.get(0).getStartPort().dataType;
        Class itemDataType = inPorts.get(1).connectedConnections.get(0).getStartPort().dataType;
        if (itemDataType.isAssignableFrom(listDataType)) {
            System.out.println("Element is not of same type as the list's");
            hasError = true;
        }
    }
    if (hasError) {
        return;
    }

    //Add item to end
    List source = (List) raw;

    //Create a new list when autoCheckBox is checked, otherwise add to existing 
    //HACK new list is created that is identical because otherwise data is not forwarded
    //When isClicked, check changes to empty circle
    if (this.autoCheckBox.isClicked()) {
        source.add(item);
        List target = new ArrayList();
        target.addAll(source);

        //Set outgoing data
        outPorts.get(0).setData(target);

    } else {
        List target = new ArrayList();
        target.addAll(source);
        target.add(item);

        //Set outgoing data
        outPorts.get(0).setData(target);
    }

}

Snippet 2计算将列表输出到文本字段的节点的功能。

    @Override
    public void calculate() {
        //Get controls and data
        TextArea area = (TextArea) controls.get(0);
        Object data = inPorts.get(0).getData();
        area.setText("");

        //Do Action
        if (inPorts.get(0).getData() != null && inPorts.get(0).connectedConnections.size() > 0) {
            //Set data type corresponding to source
            outPorts.get(0).dataType = inPorts.get(0).connectedConnections.get(0).getStartPort().dataType;
            outPorts.get(0).setName(inPorts.get(0).connectedConnections.get(0).getStartPort().getName());
            if (data instanceof List) {
                List list = (List) data;

                for (Object object : list) {
                    if (object == null) {
                        area.appendText("null");
                    } else {
                        area.appendText(object.toString() + "\n");
                    }
                }
            } else {
                area.setText(data.toString());
            }
        } else {
            //Set data type back to string
            outPorts.get(0).dataType = String.class;
            outPorts.get(0).setName("String");
            if (inPorts.get(0).isActive()) {
                area.setText("null");
            } else {
                area.setText("");
            }
        }

        //Set Data
        outPorts.get(0).setData(data);

//        System.out.println(outPorts.get(0).dataType);
    }

此异常堆栈跟踪不断重复：

    Exception in thread "JavaFX Application Thread" java.lang.ArrayIndexOutOfBoundsException: -1
    at java.util.ArrayList.elementData(ArrayList.java:418)
    at java.util.ArrayList.get(ArrayList.java:431)
    at javafx.scene.Parent.updateCachedBounds(Parent.java:1591)
    at javafx.scene.Parent.recomputeBounds(Parent.java:1535)
    at javafx.scene.Parent.impl_computeGeomBounds(Parent.java:1388)
    at javafx.scene.layout.Region.impl_computeGeomBounds(Region.java:3078)
    at javafx.scene.Node.updateGeomBounds(Node.java:3579)
    at javafx.scene.Node.getGeomBounds(Node.java:3559)
    at javafx.scene.Node.getLocalBounds(Node.java:3480)
    at javafx.scene.Node.updateTxBounds(Node.java:3643)
    at javafx.scene.Node.getTransformedBounds(Node.java:3426)
    at javafx.scene.Parent.getChildTransformedBounds(Parent.java:1732)
    at javafx.scene.Parent.updateCachedBounds(Parent.java:1596)
    at javafx.scene.Parent.recomputeBounds(Parent.java:1535)
    at javafx.scene.Parent.impl_computeGeomBounds(Parent.java:1388)
    at javafx.scene.Node.updateGeomBounds(Node.java:3579)
    at javafx.scene.Node.getGeomBounds(Node.java:3532)
    at javafx.scene.Node.impl_computeLayoutBounds(Node.java:3376)
    at javafx.scene.Group.impl_computeLayoutBounds(Group.java:165)
    at javafx.scene.Node$12.computeBounds(Node.java:3225)
    at javafx.scene.Node$LazyBoundsProperty.get(Node.java:9308)
    at javafx.scene.Node$LazyBoundsProperty.get(Node.java:9278)
    at javafx.scene.Node.getLayoutBounds(Node.java:3240)
    at javafx.scene.layout.AnchorPane.layoutChildren(AnchorPane.java:328)
    at javafx.scene.Parent.layout(Parent.java:1087)
    at javafx.scene.Scene.doLayoutPass(Scene.java:552)
    at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2397)
    at com.sun.javafx.tk.Toolkit.lambda$runPulse$30(Toolkit.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.Toolkit.runPulse(Toolkit.java:354)
    at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:381)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:510)
    at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:490)
    at com.sun.javafx.tk.quantum.QuantumToolkit.lambda$runToolkit$404(QuantumToolkit.java:319)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:748)

Answer 1

正如James_D所说：

如果您尝试从后台线程更新UI元素，则在某些情况下可能会出现这类错误。

现在，每个UI更改方法都由Platform.runLater（）从FX线程调用。