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我正在尝试根据形状绘制图形，该形状获取点的几何形状并在选择此几何形状“承载”的行后更改其颜色问题是每次选择行时都会出现此错误这是日志文件：谢谢提前

     Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at com.vividsolutions.jump.workbench.ui.renderer.java2D.Java2DConverter.toShape(Java2DConverter.java:313)
at com.vividsolutions.jump.workbench.ui.plugin.specific.SearchPropertiesPlugin$2.valueChanged(SearchPropertiesPlugin.java:144)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:167)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:147)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:194)
at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:388)
at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:398)
at javax.swing.DefaultListSelectionModel.setSelectionInterval(DefaultListSelectionModel.java:442)
at javax.swing.JTable.changeSelectionModel(JTable.java:2352)
at javax.swing.JTable.changeSelection(JTable.java:2421)
at javax.swing.plaf.basic.BasicTableUI$Handler.adjustSelection(BasicTableUI.java:1085)
at javax.swing.plaf.basic.BasicTableUI$Handler.mousePressed(BasicTableUI.java:1008)
at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:263)
at java.awt.Component.processMouseEvent(Component.java:6294)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3275)
at java.awt.Component.processEvent(Component.java:6062)
at java.awt.Container.processEvent(Container.java:2039)
at java.awt.Component.dispatchEventImpl(Component.java:4660)
at java.awt.Container.dispatchEventImpl(Container.java:2097)
at java.awt.Component.dispatchEvent(Component.java:4488)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4575)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4233)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4166)
at java.awt.Container.dispatchEventImpl(Container.java:2083)
at java.awt.Window.dispatchEventImpl(Window.java:2489)
at java.awt.Component.dispatchEvent(Component.java:4488)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:668)
at java.awt.EventQueue.access$400(EventQueue.java:81)
at java.awt.EventQueue$2.run(EventQueue.java:627)
at java.awt.EventQueue$2.run(EventQueue.java:625)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
at java.awt.EventQueue$3.run(EventQueue.java:641)
at java.awt.EventQueue$3.run(EventQueue.java:639)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:638)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

这是此错误所涉及的代码行，它发生在包含bornes（Name，X，Y）的bornesTable的侦听器中

     searchProperties.getBornesTable().getSelectionModel().addListSelectionListener(new ListSelectionListener(){

    @Override
    public void valueChanged(ListSelectionEvent e) {

        try {

            if (search()!= null){
        // here's the line 144 in toShape() method      
            final Shape shape = context.getLayerViewPanel().getViewport().getJava2DConverter().toShape(selectedBornes());
            Color color = Color.yellow;
            Stroke stroke =new BasicStroke(5, BasicStroke.CAP_ROUND,BasicStroke.JOIN_ROUND);
            final Graphics2D graphics = (Graphics2D) context.getLayerViewPanel().getGraphics();
            graphics.setColor(color);
            //graphics.setXORMode(Color.white);
            graphics.setStroke(stroke);
            graphics.fill(shape);

            }
            else
                  JOptionPane.showMessageDialog(null, "vous n'avez pas selectionner une bornes " );

        } catch (NoninvertibleTransformException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }




    }

   });

这是方法： selectedBornes()

   public Geometry selectedBornes() {

    if (getSelectedRowIndex()> 0)
    {
     Geometry geometry;
     geometry = searchBorne().get(getSelectedRowIndex()).getGeometry();
     return geometry;
    }
    return null;

}

和方法 serchBornes() 没有问题，但我会发布它

   private List<BasicFeature> searchBorne() {

    final List<BasicFeature> basicFeatureBornes = new ArrayList<BasicFeature>();

     for(BasicFeature basicFeature : BornesList) {

                if ( searchProperties.getNumTextField().getText().equals(basicFeature.getString("num")) &&
                        searchProperties.getComplementComboBox().getSelectedItem().equals(basicFeature.getString("complement")))
                    basicFeatureBornes.add(basicFeature);


                    }
     return basicFeatureBornes;

}

和 getSelectedRowIndex() 方法也没有问题，但我会发布它

    public int getSelectedRowIndex() {

    int row = 0;
     for(int i = 0; i < searchBorne().size() ; i++ ) {

          row = searchProperties.getBornesTable().getSelectedRow();

     }

    return row;

}
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2 回答 2

3 
final Shape shape = context.getLayerViewPanel().getViewport().getJava2DConverter().toShape(selectedBornes());

在这里，您直接将selectedBornes()值传递给toShape方法，但您没有检查该值是否为空，如果没有选择 RowIndex，selectedBornes()您将得到结果，因此将代码更改为NullPointerException

Goemetry newGometry=selectedBornes();
if (newGometry !=null){
final Shape shape = context.getLayerViewPanel().getViewport().getJava2DConverter().toShape(newGometry);
}
于 2013-03-11T12:29:42.793 回答
2 
public Geometry selectedBornes() {
    if (getSelectedRowIndex()> 0)
    {
     Geometry geometry;
     geometry = searchBorne().get(getSelectedRowIndex()).getGeometry();
     return geometry;
    }

如果选择的索引为 0（对于第一个元素）会发生什么？它返回 null 并且方法崩溃。如果未选择任何内容，请添加检查以处理案例。

于 2013-03-11T12:03:14.177 回答