iconandtiprenderer.java

来自「java swing 开发代码」· Java 代码 · 共 73 行

// IconAndTipRenderer.java
// A renderer for our tree cells that have icons and tooltips.
//
package	jswing.ch17;

import java.awt.*;
import javax.swing.*;
import javax.swing.tree.*;

public class IconAndTipRenderer extends JLabel implements TreeCellRenderer {

  Color backColor = new Color(0xFF, 0xCC, 0xFF);
  Icon openIcon, closedIcon, leafIcon;
  String tipText = "";

  public IconAndTipRenderer(Icon open, Icon closed, Icon leaf) {
    openIcon = open;
    closedIcon = closed;
    leafIcon = leaf;
    setBackground(backColor);
    setForeground(Color.black);
  }

  public Component getTreeCellRendererComponent(JTree tree, Object value,
                                                boolean selected,
                                                boolean expanded, boolean leaf,
                                                int row, boolean hasFocus) {
    setText(value.toString());
    if (selected) {
      setOpaque(true);
    }
    else {
      setOpaque(false);
    }

    // Try to find an IconAndTipCarrier version of the current node.
    IconAndTipCarrier itc = null;
    if (value instanceof DefaultMutableTreeNode) {
      Object uo = ((DefaultMutableTreeNode)value).getUserObject();
      if (uo instanceof IconAndTipCarrier) {
        itc = (IconAndTipCarrier)uo;
      }
    }
    else if (value instanceof IconAndTipCarrier) {
      itc = (IconAndTipCarrier)value;
    }
    if ((itc != null) && (itc.getIcon() != null)) {
      // Great! Use itc's values to customize this label
      setIcon(itc.getIcon());
      tipText = itc.getToolTipText();
    }
    else {
      // Hmmm, nothing available, so rely on the defaults.
      tipText = " ";
      if (expanded) {
        setIcon(openIcon);
      }
      else if (leaf) {
        setIcon(leafIcon);
      }
      else {
        setIcon(closedIcon);
      }
    }
    return this;
  }

  // Override the default to send back different strings for folders and leaves.
  public String getToolTipText() {
    return tipText;
  }
}