corejava第10版

corejava第10版/v1ch11/button/ButtonFrame.java

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+package button;
+
+import java.awt.*;
+import java.awt.event.*;
+import javax.swing.*;
+
+/**
+ * A frame with a button panel
+ */
+public class ButtonFrame extends JFrame
+{
+   private JPanel buttonPanel;
+   private static final int DEFAULT_WIDTH = 300;
+   private static final int DEFAULT_HEIGHT = 200;
+
+   public ButtonFrame()
+   {      
+      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
+
+      // create buttons
+      JButton yellowButton = new JButton("Yellow");
+      JButton blueButton = new JButton("Blue");
+      JButton redButton = new JButton("Red");
+
+      buttonPanel = new JPanel();
+
+      // add buttons to panel
+      buttonPanel.add(yellowButton);
+      buttonPanel.add(blueButton);
+      buttonPanel.add(redButton);
+
+      // add panel to frame
+      add(buttonPanel);
+
+      // create button actions
+      ColorAction yellowAction = new ColorAction(Color.YELLOW);
+      ColorAction blueAction = new ColorAction(Color.BLUE);
+      ColorAction redAction = new ColorAction(Color.RED);
+
+      // associate actions with buttons
+      yellowButton.addActionListener(yellowAction);
+      blueButton.addActionListener(blueAction);
+      redButton.addActionListener(redAction);
+   }
+
+   /**
+    * An action listener that sets the panel's background color.
+    */
+   private class ColorAction implements ActionListener
+   {
+      private Color backgroundColor;
+
+      public ColorAction(Color c)
+      {
+         backgroundColor = c;
+      }
+
+      public void actionPerformed(ActionEvent event)
+      {
+         buttonPanel.setBackground(backgroundColor);
+      }
+   }
+}