buttongroups.java

Thinking in JAVA第四版源代码

//: gui/ButtonGroups.java
// Uses reflection to create groups
// of different types of AbstractButton.
import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.lang.reflect.*;
import static net.mindview.util.SwingConsole.*;

public class ButtonGroups extends JFrame {
  private static String[] ids = {
    "June", "Ward", "Beaver", "Wally", "Eddie", "Lumpy"
  };
  static JPanel makeBPanel(
    Class<? extends AbstractButton> kind, String[] ids) {
    ButtonGroup bg = new ButtonGroup();
    JPanel jp = new JPanel();
    String title = kind.getName();
    title = title.substring(title.lastIndexOf('.') + 1);
    jp.setBorder(new TitledBorder(title));
    for(String id : ids) {
      AbstractButton ab = new JButton("failed");
      try {
        // Get the dynamic constructor method
        // that takes a String argument:
        Constructor ctor =
          kind.getConstructor(String.class);
        // Create a new object:
        ab = (AbstractButton)ctor.newInstance(id);
      } catch(Exception ex) {
        System.err.println("can't create " + kind);
      }
      bg.add(ab);
      jp.add(ab);
    }
    return jp;
  }
  public ButtonGroups() {
    setLayout(new FlowLayout());
    add(makeBPanel(JButton.class, ids));
    add(makeBPanel(JToggleButton.class, ids));
    add(makeBPanel(JCheckBox.class, ids));
    add(makeBPanel(JRadioButton.class, ids));
  }
  public static void main(String[] args) {
    run(new ButtonGroups(), 500, 350);
  }
} ///:~