s20.htm

Java2Swingt界面设计

            import java.util.*;
            <p>public class Test extends JApplet {<br>
              public void init() {<br>
              JTree tree = new JTree();<br>
              JScrollPane scrollPane = new JScrollPane(tree);<br>
              JComboBox combo = new JComboBox();</p>
            <p> combo.addItem(&quot;red&quot;);<br>
              combo.addItem(&quot;blue&quot;);<br>
              combo.addItem(&quot;green&quot;);<br>
              combo.addItem(&quot;orange&quot;);<br>
              combo.addItem(&quot;yellow&quot;);<br>
              combo.addItem(&quot;magenta&quot;);</p>
            <p> tree.setCellEditor(new DefaultTreeCellEditor(<br>
              tree, new DefaultTreeCellRenderer(),<br>
              new ColorEditor(tree, combo)));</p>
            <p> tree.setEditable(true);</p>
            <p> getContentPane().add(scrollPane);<br>
              }<br>
              }<br>
              class ColorEditor extends DefaultCellEditor {<br>
              private JTree tree;</p>
            <p> public ColorEditor(JTree tree, JComboBox comboBox) {<br>
              super(comboBox);<br>
              this.tree = tree;<br>
              }<br>
              public boolean isCellEditable(EventObject e) {<br>
              boolean rv = false; // return value</p>
            <p> if(e instanceof MouseEvent) {<br>
              MouseEvent me = (MouseEvent)e;</p>
            <p> if(me.getClickCount() == 3) {<br>
              TreePath path =<br>
              tree.getPathForLocation(me.getX(), me.getY()); </p>
            <p> if(path.getPathCount() == 1) // root node<br>
              return false;</p>
            <p> DefaultMutableTreeNode node = <br>
              (DefaultMutableTreeNode)<br>
              path.getLastPathComponent(); <br>
              <br>
              rv = node.getParent().toString().equals(&quot;colors&quot;);<br>
              }<br>
              }<br>
              return rv;<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p> 20.8 绘制和编辑：学习一个样例</p>
            <p>&nbsp;</p>
            <p> 20.8.1 Test类</p>
            <p>&nbsp;</p>
            <p align="center"><b>例20-15 绘制和编辑：一个学习样例</b></p>
            <hr noshade size="1">
            import javax.swing.*;<br>
            import javax.swing.event.*;<br>
            import javax.swing.tree.*;<br>
            import java.awt.*;<br>
            import java.awt.event.*;<br>
            import java.io.File;<br>
            import java.util.EventObject;
            <p>public class Test extends JFrame {<br>
              public Test() {<br>
              JTree tree = new JTree(createTreeModel());<br>
              JScrollPane scrollPane = new JScrollPane(tree);</p>
            <p> FileNodeRenderer renderer = new FileNodeRenderer();<br>
              FileNodeEditor editor = new FileNodeEditor();<br>
              <br>
              tree.setEditable(true);<br>
              tree.setCellRenderer(renderer);<br>
              tree.setCellEditor(new ImmediateEditor(tree, <br>
              renderer, editor));</p>
            <p> getContentPane().add(scrollPane, BorderLayout.CENTER);</p>
            <p> tree.addTreeExpansionListener(new TreeExpansionListener(){<br>
              public void treeCollapsed(TreeExpansionEvent e) {<br>
              }<br>
              public void treeExpanded(TreeExpansionEvent e) {<br>
              TreePath path = e.getPath();<br>
              FileNode node = (FileNode)<br>
              path.getLastPathComponent();</p>
            <p> if( ! node.isExplored())<br>
              node.explore();<br>
              }<br>
              });<br>
              tree.getCellEditor().addCellEditorListener(<br>
              new CellEditorListener() {<br>
              public void editingCanceled(ChangeEvent e) {<br>
              CellEditor cellEditor = (CellEditor)e.getSource();<br>
              SelectableFile sf = <br>
              (SelectableFile)<br>
              cellEditor.getCellEditorValue();</p>
            <p> System.out.println(&quot;editing canceled: &quot; + <br>
              sf.toString());<br>
              }<br>
              public void editingStopped(ChangeEvent e) {<br>
              CellEditor cellEditor = (CellEditor)e.getSource();<br>
              SelectableFile sf = <br>
              (SelectableFile)<br>
              cellEditor.getCellEditorValue();</p>
            <p> System.out.println(&quot;editing stopped: &quot; + <br>
              sf.toString());<br>
              }<br>
              });<br>
              }<br>
              private DefaultTreeModel createTreeModel() {<br>
              File root = new File(&quot;E:/&quot;);<br>
              FileNode rootNode = new FileNode(root), node;</p>
            <p> rootNode.explore();<br>
              return new DefaultTreeModel(rootNode);<br>
              }<br>
              public static void main(String args[]) {<br>
              GJApp.launch(new Test(),&quot;JTree File Explorer&quot;,<br>
              300,300,450,400);<br>
              }<br>
              }<br>
              class SelectableFile {<br>
              private File file;<br>
              private boolean selected = false;</p>
            <p> public SelectableFile(File file) {<br>
              this.file = file;<br>
              }<br>
              public String toString() {<br>
              return file.toString() + &quot; selected: &quot; + selected;<br>
              }<br>
              public void setSelected(boolean s) { selected = s; }<br>
              public boolean isSelected() { return selected; }<br>
              public File getFile() { return file; }<br>
              }<br>
              class FileNode extends DefaultMutableTreeNode {<br>
              private boolean explored = false;</p>
            <p> public FileNode(File file) { <br>
              setUserObject(new SelectableFile(file)); <br>
              }<br>
              public boolean getAllowsChildren() { return isDirectory(); }<br>
              public boolean isLeaf() { return !isDirectory(); }</p>
            <p> public File getFile() { <br>
              SelectableFile sf = (SelectableFile)getUserObject(); <br>
              return sf.getFile();<br>
              }<br>
              public boolean isSelected() {<br>
              SelectableFile sf = (SelectableFile)getUserObject(); <br>
              return sf.isSelected();<br>
              }<br>
              public void setSelected(boolean b) {<br>
              SelectableFile sf = (SelectableFile)getUserObject(); <br>
              sf.setSelected(b);<br>
              }<br>
              public boolean isDirectory() {<br>
              File file = getFile();<br>
              return file.isDirectory();<br>
              }<br>
              public String toString() {<br>
              File file = getFile();<br>
              String filename = file.toString();<br>
              int index = filename.lastIndexOf(&quot;\\&quot;);</p>
            <p> return (index != -1 &amp;&amp; index != filename.length()-1) ? 
              <br>
              filename.substring(index+1) : <br>
              filename;<br>
              }<br>
              public void explore() { explore(false); }<br>
              public boolean isExplored() { return explored; }</p>
            <p> public void explore(boolean force) {<br>
              if(!isExplored() || force) {<br>
              File file = getFile();<br>
              File[] children = file.listFiles();</p>
            <p> for(int i=0; i &lt; children.length; ++i) <br>
              add(new FileNode(children[i]));</p>
            <p> explored = true;<br>
              }<br>
              }<br>
              }<br>
              class FileNodeRenderer extends DefaultTreeCellRenderer {<br>
              protected JCheckBox checkBox = new JCheckBox(&quot;backup&quot;);<br>
              private Component strut = Box.createHorizontalStrut(5);<br>
              private JPanel panel = new JPanel();</p>
            <p> public FileNodeRenderer() {<br>
              panel.setBackground(<br>
              UIManager.getColor(&quot;Tree.textBackground&quot;));<br>
              <br>
              setOpaque(false);<br>
              checkBox.setOpaque(false);<br>
              panel.setOpaque(false);</p>
            <p> panel.setLayout(new FlowLayout(FlowLayout.CENTER,0,0));<br>
              panel.add(this);<br>
              panel.add(strut);<br>
              panel.add(checkBox);</p>
            <p> } <br>
              public Component getTreeCellRendererComponent(<br>
              JTree tree, Object value, <br>
              boolean selected, boolean expanded,<br>
              boolean leaf, int row, <br>
              boolean hasFocus) {<br>
              FileNode node = (FileNode)value;</p>
            <p> super.getTreeCellRendererComponent(<br>
              tree, value, selected, expanded,<br>
              leaf, row, hasFocus);</p>
            <p> checkBox.setVisible(node.isDirectory());<br>
              checkBox.setSelected(node.isSelected());</p>
            <p> return panel;<br>
              }<br>
              public Dimension getCheckBoxOffset() {<br>
              Graphics g = panel.getGraphics();<br>
              int xoffset = 0;</p>
            <p> if(g != null) {<br>
              try {<br>
              FontMetrics fm = g.getFontMetrics();<br>
              xoffset = fm.stringWidth(getText()) + <br>
              strut.getPreferredSize().width;<br>
              }<br>
              finally {<br>
              g.dispose();<br>
              }<br>
              }<br>
              return new Dimension(xoffset, 0);<br>
              }<br>
              }<br>
              class FileNodeEditorRenderer extends FileNodeRenderer {<br>
              public Component getTreeCellRendererComponent(<br>
              JTree tree, Object value, <br>
              boolean selected, boolean expanded,<br>
              boolean leaf, int row, <br>
              boolean hasFocus) {<br>
              Component c = super.getTreeCellRendererComponent(tree, <br>
              value, selected, expanded, <br>
              leaf, row, hasFocus);<br>
              setIcon(null);<br>
              return c;<br>
              }<br>
              public JCheckBox getCheckBox() {<br>
              return checkBox;<br>
              }<br>
              }<br>
              class FileNodeEditor extends Abs