Java 动态更改JTree的节点映像
我正在使用CustomCellRenderer显示JTree的节点,以显示节点为的图像 如下所示:-Java 动态更改JTree的节点映像,java,swing,jtree,Java,Swing,Jtree,我正在使用CustomCellRenderer显示JTree的节点,以显示节点为的图像 如下所示:- class CustomTreeCellRenderer extends DefaultTreeCellRenderer{ public Component getTreeCellRendererComponent(JTree tree, Object value, boolean selected, boolean expanded, boolean
class CustomTreeCellRenderer extends DefaultTreeCellRenderer{
public Component getTreeCellRendererComponent(JTree tree,
Object value, boolean selected, boolean expanded,
boolean leaf, int row, boolean hasFocus){
super.getTreeCellRendererComponent(tree, value,
selected, expanded, leaf, row, hasFocus);
JLabel label = (JLabel) this ;
label.setIcon( new ImageIcon("white.png") ) ;
return this;
}
}
public void actionPerformed(ActionEvent ae) {
DefaultTreeModel model = (DefaultTreeModel) tree.getModel() ;
JLabel label = (JLabel) tree.getCellRenderer() ;
System.out.println(label.getIcon()); //displaying white.png
label.setIcon( new ImageIcon("black.gif") ) ;
model.reload() ;
}
我的要求是在某些外部操作上更改节点的映像。
我正在尝试重新加载JTree的模型,但它无法正常工作,如下所示:-
class CustomTreeCellRenderer extends DefaultTreeCellRenderer{
public Component getTreeCellRendererComponent(JTree tree,
Object value, boolean selected, boolean expanded,
boolean leaf, int row, boolean hasFocus){
super.getTreeCellRendererComponent(tree, value,
selected, expanded, leaf, row, hasFocus);
JLabel label = (JLabel) this ;
label.setIcon( new ImageIcon("white.png") ) ;
return this;
}
}
public void actionPerformed(ActionEvent ae) {
DefaultTreeModel model = (DefaultTreeModel) tree.getModel() ;
JLabel label = (JLabel) tree.getCellRenderer() ;
System.out.println(label.getIcon()); //displaying white.png
label.setIcon( new ImageIcon("black.gif") ) ;
model.reload() ;
}
我做错了什么?将图标作为字段添加到渲染器类中 更改此字段的值并重新绘制JTree
class CustomTreeCellRenderer extends DefaultTreeCellRenderer{
ImageIcon rendererIcon;
public void setRendererIcon(ImageIcon myIcon){
this.rendererIcon = myIcon;
};
public Component getTreeCellRendererComponent(JTree tree,
Object value, boolean selected, boolean expanded,
boolean leaf, int row, boolean hasFocus){
super.getTreeCellRendererComponent(tree, value,
selected, expanded, leaf, row, hasFocus);
JLabel label = (JLabel) this ;
label.setIcon( rendererIcon ) ;
return this;
}
}
编辑:解释
在您的情况下,更改模型是无用的。用于显示每个节点的图标是渲染器的一部分
JTree的渲染器对象不强制为JComponent
。当代码调用gettreecellrendercomponent
时,它必须是一个提供JComponent
的对象
在您的例子中,将getCellRenderer()转换为JLabel纯粹是运气,因为DefaultTreeCellRenderer
的默认实现是JLabel
的扩展
事实上,由于渲染器本身调用了setIcon,所以getIcon方法通常会给出最后一个放入渲染器的图标
完整代码工作:
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.tree.DefaultTreeCellRenderer;
public class TestJTree {
private static ImageIcon iconWhite = new ImageIcon("white.jpg");
private static ImageIcon iconBlack = new ImageIcon("black.jpg");;
public static void main(String[] args) {
TestJTree me = new TestJTree();
me.process();
}
private void process() {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
initGui();
}
});
}
protected void initGui() {
JFrame frame = new JFrame("Test JTree");
frame.setContentPane(new JPanel(new BorderLayout()));
final JTree tree = new JTree();
frame.getContentPane().add(tree);
final CustomTreeCellRenderer renderer = new CustomTreeCellRenderer();
renderer.setRendererIcon(iconWhite);
tree.setCellRenderer(renderer);
JPanel panelButtons = new JPanel();
JButton buttonWhite = new JButton("");
buttonWhite.setIcon(iconWhite);
JButton buttonBlack = new JButton("");
buttonBlack.setIcon(iconBlack);
buttonBlack.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
renderer.setRendererIcon(iconBlack);
tree.repaint();
}
});
panelButtons.add(buttonBlack);
panelButtons.add(buttonWhite);
frame.getContentPane().add(panelButtons,BorderLayout.SOUTH);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500,500);
frame.setVisible(true);
}
@SuppressWarnings("serial")
private static class CustomTreeCellRenderer extends DefaultTreeCellRenderer{
ImageIcon rendererIcon;
public void setRendererIcon(ImageIcon myIcon){
this.rendererIcon = myIcon;
};
public Component getTreeCellRendererComponent(JTree tree,
Object value, boolean selected, boolean expanded,
boolean leaf, int row, boolean hasFocus){
Component ret = super.getTreeCellRendererComponent(tree, value,
selected, expanded, leaf, row, hasFocus);
JLabel label = (JLabel) ret ;
label.setIcon( rendererIcon ) ;
return ret;
}
}
}
有两点:
actionPerformed
的方法从表中获取渲染器并对其进行修改不是常见做法。应该注意,渲染器是共享的,因此将影响列中使用该渲染器的所有单元格操作期间在渲染器实例上设置了图标
,渲染器始终通过GetTreeCellRenderComponent
方法访问以进行绘制,并且您始终将图标设置为“white.png”,因此您永远不会显示“black.gif”
actionPerformed
方法中设置模型的状态,然后从gettreecellrendercomponent
中查询要显示的图标
例如:
public void actionPerformed(ActionEvent ae) {
MyCustomTreeModel model = (MyCustomTreeModel) tree.getModel() ;
...
model.setMyState(state); //set the state based on the action
}
在渲染器中:
public Component getTreeCellRendererComponent(JTree tree,
Object value, boolean selected, boolean expanded,
boolean leaf, int row, boolean hasFocus)
{
MyCustomTreeModel model = (MyCustomTreeModel) tree.getModel();
....
setIcon(model.getMyIconBasedOnTheStateISetInActionPerformed());
return this;
}
那么如何解决这个问题呢。请用代码解释。:)是的,它正在更改整个树的图标,而不是所选节点的图标。