Question

我正在开发一个女巫应用程序，我的桌子上有一个数字，数字10的下标是绿色，其余的则用LIGHT_GRAY着色为此，我使用了TABLECELLRENDERER，但它一直告诉我有错误，我无法确切地找出错误所在，因此我向您寻求帮助，如果您不能我想将其应用于所有表的另一件事是我在上面为一列编写的代码，如何在所有列上进行转换谢谢

import java.awt.Color;
import java.awt.Component;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.TableCellRenderer;

public class RenduCellule extends DefaultTableCellRenderer {


    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected,
            boolean hasFocus, int row, int column) {
        super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
        Component c = getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
        if (column == 2) {
       float val = Float.parseFloat(table.getValueAt(row,column)+"");
            Color color = null;
            if (val < 10)
                color = Color.green;
            else
                color = Color.LIGHT_GRAY;

            c.setBackground(color);
        } else
            c.setBackground(Color.pink);
        return c;

    }
}

这是我写的主要内容

jTable.setDefaultRenderer(Object.class, new RenduCellule());

这是错误

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at sagem02.RenduCellule.getTableCellRendererComponent(RenduCellule.java:17)
at javax.swing.JTable.prepareRenderer(JTable.java:5723)
at javax.swing.plaf.basic.BasicTableUI.paintCell(BasicTableUI.java:2114)
at javax.swing.plaf.basic.BasicTableUI.paintCells(BasicTableUI.java:2016)
at javax.swing.plaf.basic.BasicTableUI.paint(BasicTableUI.java:1812)
at javax.swing.plaf.ComponentUI.update(ComponentUI.java:161)
at javax.swing.JComponent.paintComponent(JComponent.java:780)
at javax.swing.JComponent.paint(JComponent.java:1056)
at javax.swing.JComponent.paintChildren(JComponent.java:889)
at javax.swing.JComponent.paint(JComponent.java:1065)
at javax.swing.JViewport.paint(JViewport.java:728)
at javax.swing.JComponent.paintChildren(JComponent.java:889)
at javax.swing.JComponent.paint(JComponent.java:1065)
at javax.swing.JComponent.paintChildren(JComponent.java:889)
at javax.swing.JComponent.paint(JComponent.java:1065)
at javax.swing.JComponent.paintChildren(JComponent.java:889)
at javax.swing.JComponent.paint(JComponent.java:1065)
at javax.swing.JComponent.paintChildren(JComponent.java:889)
at javax.swing.JComponent.paint(JComponent.java:1065)
at javax.swing.JLayeredPane.paint(JLayeredPane.java:586)
at javax.swing.JComponent.paintChildren(JComponent.java:889)
at javax.swing.JComponent.paintToOffscreen(JComponent.java:5217)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1579)
at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1502)
at javax.swing.RepaintManager.paint(RepaintManager.java:1272)
at javax.swing.JComponent.paint(JComponent.java:1042)
at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:39)
at sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:79)
at sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:116)
at java.awt.Container.paint(Container.java:1975)
at java.awt.Window.paint(Window.java:3912)
at javax.swing.RepaintManager$4.run(RepaintManager.java:842)
at javax.swing.RepaintManager$4.run(RepaintManager.java:814)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:814)
at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:789)
at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:738)
at javax.swing.RepaintManager.access$1200(RepaintManager.java:64)
at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1732)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
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.awt.EventQueue.dispatchEvent(EventQueue.java:726)
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)

Answer 1

private static final TableCellRenderer RENDERER = new DefaultTableCellRenderer();

不需要。

Component c = RENDERER.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

应该是：

Component c = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

那是您需要先调用渲染器的默认逻辑，然后再调用自定义渲染代码。

还

Object result = table.getModel().getValueAt(row, column);

应为：

Object result = table.getValueAt(row, column);

因为行/列是相对于视图（表）而不是模型的。如果您的表格是经过排序或过滤的，则表格的行/列值将不直接与模型匹配。

编辑：

super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
 Component c = getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

为什么有两行代码？我的建议只有一行代码。

覆盖方法是Java的基本功能，对渲染器类而言并没有特定的含义。

通常要覆盖某个方法，您可以执行以下操作：

public Component getTableCellRendererComponent(...)
{
    super.getTableCellRendererComponent(...);

    setBackground(Color.RED);

    return this;
}

或者因为该方法返回执行渲染的组件，所以您可以这样做：

public Component getTableCellRendererComponent(...)
{
    Component c = super.getTableCellRendererComponent(...);

    c.setBackground(Color.RED);

    return c;
}

如果您不知道如何使用方法，请使用方法名称搜索论坛，以在论坛中找到其他示例。利用论坛和网络上的所有信息。

jtable的着色单元格引用数字

1 个答案: