unicodedisplay.java

java小例程3。多个小例程

// 导入所需要的Java类库
import javax.swing.*; 
import java.awt.*;
import java.awt.event.*;

public class UnicodeDisplay extends JFrame implements ActionListener {
    
int page = 0;
    UnicodePanel p;
    JScrollBar b;
    String fontfamily = "Serif";
    int fontstyle = Font.PLAIN;

    /**
     * 构造函数，创建frame、菜单和滚动条
     **/
    public UnicodeDisplay(String name) {
        super(name);
        p = new UnicodePanel();              // 创建panel
        p.setBase((char)(page * 0x100));       // 初始化panel
        getContentPane().add(p, "Center");     // 使其居中

        // Create and set up a scrollbar, and put it on the right
        b = new JScrollBar(Scrollbar.VERTICAL, 0, 1, 0, 0xFF);
        b.setUnitIncrement(1);
        b.setBlockIncrement(0x10);
        b.addAdjustmentListener(new AdjustmentListener() {
		public void adjustmentValueChanged(AdjustmentEvent e) {
		    page = e.getValue();
		    p.setBase((char)(page * 0x100));
		}
	    });
        getContentPane().add(b, "East");

        // 设置消息响应函数处理关闭窗口请求
        this.addWindowListener(new WindowAdapter() {
		public void windowClosing(WindowEvent e) { System.exit(0); }
	    });

        //  响应PageUP、PageDown、Up和Down按键
        this.addKeyListener(new KeyAdapter() {
		public void keyPressed(KeyEvent e) {
		    int code = e.getKeyCode();
		    int oldpage = page;
		    if ((code == KeyEvent.VK_PAGE_UP) ||
			(code == KeyEvent.VK_UP)) {
			if (e.isShiftDown()) page -= 0x10;
			else page -= 1;
			if (page < 0) page = 0;
		    }
		    else if ((code == KeyEvent.VK_PAGE_DOWN) ||
			     (code == KeyEvent.VK_DOWN)) {
			if (e.isShiftDown()) page += 0x10;
			else page += 1;
			if (page > 0xff) page = 0xff;
		    }
		    if (page != oldpage) {     //如果改变了当前显示页...
			p.setBase((char) (page * 0x100)); // 更新显示
			b.setValue(page);     // 更新滚动条
		    }
		}
	    });

        // 建立可以改变显示字体的菜单.
        JMenuBar menubar = new JMenuBar();
        this.setJMenuBar(menubar);
        menubar.add(makemenu("Font Family",
			     new String[] {"Serif", "SansSerif", "Monospaced"},
			     this));
        menubar.add(makemenu("Font Style",
			     new String[]{
				 "Plain","Italic","Bold","BoldItalic"
			     }, this));
    }