GUI 下

11.6 Swing组件

JButton JLabel JTextField JTextArea JTable JTree

publicclass JTableDemo extends JFrame

{

      publicstaticvoid main(String[] args)

      {

           JTableDemo jTableDemo = new JTableDemo();

           jTableDemo.setVisible(true);

      }

      public JTableDemo()

      {

           setSize(300, 300);

           setLocation(400, 400);

           setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

           setLayout(new BorderLayout());

           JTable table = new JTable(new AbstractTableModel()

           {

                 privatestaticfinallongserialVersionUID = 1L;

                 private String columnName[] =

                 { "第一列", "第二列", "第三列", "第四列" };

                 // 返回列的大小

                 @Override

                 publicint getColumnCount()

                 {

                      return 4;

                 }

                 // 返回列名

                 @Override

                 public String getColumnName(intcolumn)

                 {

                      returnthis.columnName[column];

                 }

                 // 返回行的大小

                 @Override

                 publicint getRowCount()

                 {

                      return 4;

                 }

                 public Object getValueAt(introw, intcol)

                 {

                      returnnew Integer(row * col);

                 }

           });

           // 为了防止表格过长,使用JScrollPane,使得表格具有滚动条

           JScrollPane scrollPane = new JScrollPane(table);

           add(scrollPane, BorderLayout.CENTER);

      }}

11.7 图形编程

11.7.1 AWT图形API

Graphics 类是从JDK1.0开始就在AWT中提供的图形绘制类.由于Swing是基于AWT发展起来的组件,Graphics类作为一种图形绘制方式得到了保留

drawLine	绘制直线
DrawOval fillOval	绘制椭圆 填充椭圆
DrawPolygon FillPolygon	绘制多边形 填充多边形
drawRect fillRect	绘制矩形 填充矩形
drawRoundRect fillRoundRect	绘制圆角矩阵 填充圆角矩阵
drawstring	绘制字符串
Draw3DRect Fill3DRect	绘制带3D效果的矩形 填充带3D效果的矩形
drawImage	绘制图片
SetColor	设置画笔颜色
SetFont	设置字体

publicclass GraphicsDemo extends JFrame

{

      publicstaticvoid main(String[] args)

      {

           GraphicsDemo graphicsDemo = new GraphicsDemo();

           graphicsDemo.setVisible(true);

      }

      public GraphicsDemo()

      {

           setSize(400, 400);

           setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

      }

      @Override

      publicvoid paint(Graphics g)

      {

           super.paint(g);

           // 设置画笔颜色为红色

      g.setColor(Color.red);

           // 绘制矩形

           g.drawRect(50, 50, 100, 100);

           // 填充矩形

           g.fillRect(200, 50, 100, 100);

           // 设置画笔颜色为绿色

           g.setColor(Color.green);

           // 绘制圆形

           g.drawOval(50, 200, 100, 100);

           // 填充圆形

           g.fillOval(200, 200, 100, 100);

      }}

11.7.2 Java2D 图形API

 Java2D 是JFC的一员,加强了传统的AWT的描绘功能.

      绘制五角形代码如下

      publicclass Graphics2DDemo extends JFrame

{

      publicstaticvoid main(String[] args)

      {

           Graphics2DDemo myFrame = new Graphics2DDemo();

           myFrame.setVisible(true);

      }

      public Graphics2DDemo()

      {

           setSize(400, 400);

           setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

      }

      @Override

      publicvoid paint(Graphics g)

      {

           super.paint(g);

           Graphics2D g2 = (Graphics2D) g;

           // 设置画笔样式

           g2.setStroke(new BasicStroke(4.0f));

           // 用GeneralPath 构造一个五角形

           GeneralPath p = new GeneralPath(GeneralPath.WIND_NON_ZERO);

           p.moveTo(-100.0f, -25.0f);

           p.lineTo(+100.0f, -25.0f);

           p.lineTo(-50.0f, +100.0f);

           p.lineTo(+0.0f, -100.0f);

           p.lineTo(+50.0f, +100.0f);

           p.closePath();

           // 将坐标平移到(200,200)

           g2.translate(200.0f, 200.0f);

           g2.draw(p);

      }}

11.8 加载和使用多媒体资源

11.8.1 加载图像

      现在我使用一种基于ImageIO的图像加载和使用方法.ImageIo中关于图像加载的方法主要有以下的方法

      BufferedImage read(File input)

      BufferedImage read(ImageInputStream stream)

BufferedImage read(InputStream input)

BufferedImage read(URL input)