Java 如何实现侦听器?
我有一些动态树。现在我需要实现一些功能,每次只需单击节点就可以实现这些功能。(我的意思是只需点击一次节点,它就会“变蓝”) **EDIT2:*我使用beanTreeView和包openide 如何实现此操作的侦听器 编辑-添加伪代码Java 如何实现侦听器?,java,listener,openide,Java,Listener,Openide,我有一些动态树。现在我需要实现一些功能,每次只需单击节点就可以实现这些功能。(我的意思是只需点击一次节点,它就会“变蓝”) **EDIT2:*我使用beanTreeView和包openide 如何实现此操作的侦听器 编辑-添加伪代码 public class MyNode extends AbstractNode{ //openide package private String name; public MyNode(String nameOfNode){ supe
public class MyNode extends AbstractNode{ //openide package
private String name;
public MyNode(String nameOfNode){
super (new Children.LEAF);
name = nameOfNode;
}
....
....
}
public class IWantNameOfSelectedNode extends JPanel{
private JLabel jLnameOfNode;
public IWantNameOfSelectedNode(){
jLnameOfNode.setText("wiating for node selection");
}
现在,我需要将所选节点的名称放入jLabel,并在每次节点选择更改时更改它。我假设它是一个Swing树。您可以通过使用CustomRenderer组件或TreeSelectionListener接口来实现这一点 这有一个关于如何改变图标、背景等的高级示例教程。您需要的是一个比这个简单得多的版本 您感兴趣的代码是
public Component getTreeCellRendererComponent( JTree tree,
Object value, boolean bSelected, boolean bExpanded,
boolean bLeaf, int iRow, boolean bHasFocus )
{
// Find out which node we are rendering and get its text
DefaultMutableTreeNode node = (DefaultMutableTreeNode)value;
String labelText = (String)node.getUserObject();
this.bSelected = bSelected;
// Set the correct foreground color
if( !bSelected )
setForeground( Color.black );
else
setForeground( Color.white );
....
}
假设您使用的是Swing
JTree
类,您应该定义一个TreeSelectionListener
,并将其添加到底层的TreeModel
。如果您希望使用ActionListener
,则需要编写一些适配器代码来将TreeSelectionEvent
s转换为ActionEvent
s(尽管这实际上毫无意义)
示例
/**
* Adapter class responsible for translating TreeSelectionEvents into
* ActionEvents.
*/
public class TreeSelectionAdapter implements TreeSelectionListener {
private final AtomicInteger nextId = new AtomicInteger(0);
// Prefer CopyOnWriteArrayList to avoid ConcurrentModificationException if an
// ActionListener removes itself as a listener during notification.
private final CopyOnWriteArrayList<ActionListener> listeners;
public TreeSelectionAdapter() {
this.listeners = new CopyOnWriteArrayList<ActionListener();
}
public void addActionListener(ActionListener l) {
this.listeners.add(l);
}
public void removeActionListener(ActionListener l) {
this.listeners.remove(l);
}
public void valueChanged(TreeSelectionEvent evt) {
// Create new ActionEvent which corresponds to incoming TreeSelectionEvent
// and notify registered ActionListeners.
ActionEvent aEvt = new ActionEvent(evt.getSource(),
nextId.getAndIncrement(), "selectionChanged");
for (ActionListener listener : listeners) {
listener.actionPerformed(listener);
}
}
}
TreeNode rootNode = createTreeModel(); // Create custom model
JTree tree = new JTree(rootNode); // Install model into JTree.
// Add adapter listener to underlying selection model.
tree.getSelectionModel().addTreeSelectionListener(adapter);
// Register ActionListener with adapter listener.
adapter.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
System.err.println("Selection has changed in some way!");
}
});
/**
*适配器类负责将TreeSelectionEvents转换为
*行动事件。
*/
公共类TreeSelectionAdapter实现TreeSelectionListener{
私有最终AtomicInteger nextId=新的AtomicInteger(0);
//如果
//ActionListener在通知期间将自身作为侦听器删除。
私有最终CopyOnWriteArrayList侦听器;
公用树选择适配器(){
this.listeners=new copyonwritearraylist也许你已经有了一些我们将从中开始的代码?目前你只能获得sun教程的链接(实际上应该足够了)除了上面Roman所说的,一旦您了解了侦听器,我建议您检查匿名内部类。它们可以帮助侦听器在实现IMO时减少一些麻烦。我需要类间actionListener。请参阅我提出问题的代码