Question

我在GUI应用程序中使用JavaFX和Swing。更详细的说，我在AnchorPane之上使用SwingNode来添加一个JPanel，并在其上添加一些地图（ARCGIS JMap - 只在秋千上运行），它会一直刷新。

当我在两个显示屏幕之间拖动我的应用程序时，有时候我有一个NullPointerException。

这是它发生的java代码：

MouseInfo.getPointerInfo().getLocation()

在JavaFX元素上执行拖动（事件是JavaFX事件）：

    private void setDraggable(Parent root) {
    if (root != null) {
        root.setOnMousePressed((event) -> {
            xOffset = mainStage.getX() - event.getScreenX();
            yOffset = mainStage.getY() - event.getScreenY();
        });

        root.setOnMouseDragged((event) -> {
            mainStage.setX(event.getScreenX() + xOffset);
            mainStage.setY(event.getScreenY() + yOffset);
        });
    }

但是这个例外发生在AWT线程上正如我所说，它所代码的代码是（请注意这是内部java代码，而不是我的代码）：

MouseInfo.getPointerInfo().getLocation()

我该怎么做才能防止这种情况发生？

另一个问题，也许会给出一个线索 - 我检查过，我唯一的Swing组件（JPanel和JMap）都是JComponent的子组件。但是JLightweightFrame中发生异常。那怎么可能呢？

以下是异常的完整描述：

Message = Thread AWT-EventQueue-0 (Id = 45) throw exception: null Stack-Trace = java.lang.NullPointerException
    at sun.swing.JLightweightFrame.updateClientCursor(JLightweightFrame.java:473)
    at sun.swing.JLightweightFrame.access$000(JLightweightFrame.java:79)
    at sun.swing.JLightweightFrame$1.updateCursor(JLightweightFrame.java:112)
    at sun.awt.windows.WLightweightFramePeer.updateCursorImmediately(WLightweightFramePeer.java:92)
    at java.awt.Component.updateCursorImmediately(Component.java:3150)
    at java.awt.Container.validate(Container.java:1642)
    at java.awt.Window.dispatchEventImpl(Window.java:2748)
    at java.awt.Component.dispatchEvent(Component.java:4713)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.awt.EventQueue$4.run(EventQueue.java:731)
    at java.awt.EventQueue$4.run(EventQueue.java:729)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

MouseInfo.getPointerInfo（）中的异常.getLocation（）

0 个答案: