s13.htm

提供给JAVA编程者图形界面卷

              viewPositionLabel.setText(&quot;View Position: &quot; + <br>
              viewPosition.toString());<br>
              viewSizeLabel.setText(&quot;View Size: &quot; + <br>
              viewSize.toString());<br>
              revalidate();<br>
              }<br>
              });<br>
              }<br>
              }<br>
              class ControlPanel extends JPanel { <br>
              private JViewport viewport;</p>
            <p> private JButton[] buttons = {<br>
              new JButton(&quot;up&quot;), new JButton(&quot;down&quot;),<br>
              new JButton(&quot;left&quot;), new JButton(&quot;right&quot;),<br>
              };</p>
            <p> public ControlPanel(JViewport vp) {<br>
              viewport = vp;</p>
            <p> for(int i=0; i &lt; buttons.length; ++i) {<br>
              add(buttons[i]);</p>
            <p> buttons[i].addActionListener(new ActionListener() {<br>
              public void actionPerformed(ActionEvent e) {<br>
              scroll(e.getActionCommand());<br>
              }<br>
              });<br>
              }<br>
              }<br>
              private void scroll(String actionCmd) {<br>
              Point vp = viewport.getViewPosition();</p>
            <p> if(actionCmd.equals(&quot;up&quot;)) vp.y += 5; <br>
              else if(actionCmd.equals(&quot;down&quot;)) vp.y -= 5; <br>
              else if(actionCmd.equals(&quot;left&quot;)) vp.x += 5; <br>
              else if(actionCmd.equals(&quot;right&quot;)) vp.x -= 5; </p>
            <p> viewport.setViewPosition(vp);<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p> 13.1.5 JViewport类总结</p>
            <p>&nbsp;</p>
            <p>13.1.6 AWT兼容</p>
            <p>&nbsp;</p>
            <p align="center"><b>例13-5 使用JScrollPane</b></p>
            <hr noshade size="1">
            import java.awt.*;<br>
            import java.awt.event.*;<br>
            import javax.swing.*;<br>
            import javax.swing.event.*;
            <p>public class Test extends JApplet {<br>
              public Test() {<br>
              Container contentPane = getContentPane();<br>
              JLabel view = new JLabel(new ImageIcon(&quot;cutlery.jpg&quot;,<br>
              &quot;A picture of cutlery&quot;));<br>
              JScrollPane sp = new JScrollPane(view);</p>
            <p> contentPane.add(sp);<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p> 13.2 JScrollPane</p>
            <p>&nbsp;</p>
            <p> 13.2.1 滚动窗格的头部</p>
            <p>&nbsp;</p>
            <p align="center"><b>例13-6 为滚动窗格的头部指定视图</b></p>
            <hr noshade size="1">
            import java.awt.*;<br>
            import javax.swing.*;
            <p>public class Test extends JApplet {<br>
              public Test() {<br>
              Container contentPane = getContentPane();<br>
              JLabel columnHeaderView = new JLabel(<br>
              new ImageIcon(&quot;horizontalRuler.jpg&quot;,<br>
              &quot;horizontal ruler&quot;));<br>
              JLabel rowHeaderView = new JLabel(<br>
              new ImageIcon(&quot;verticalRuler.jpg&quot;,<br>
              &quot;vertical ruler&quot;));<br>
              JLabel view = new JLabel(<br>
              new ImageIcon(&quot;grapes.jpg&quot;,<br>
              &quot;grapes&quot;));</p>
            <p> JScrollPane sp = new JScrollPane(view);</p>
            <p> sp.setColumnHeaderView(columnHeaderView);<br>
              sp.setRowHeaderView(rowHeaderView);</p>
            <p> sp.setViewportBorder(<br>
              BorderFactory.createRaisedBevelBorder());</p>
            <p> contentPane.add(sp);<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p align="center"><b>例13-7 设置头部视口</b></p>
            <hr noshade size="1">
            import java.awt.*;<br>
            import java.awt.event.*;<br>
            import javax.swing.*;
            <p>public class Test extends JApplet {<br>
              public void init() {<br>
              Container contentPane = getContentPane();<br>
              JViewport columnHeaderViewport = new JViewport();<br>
              JViewport rowHeaderViewport = new JViewport();</p>
            <p> JLabel columnHeaderView = new JLabel(<br>
              new ImageIcon(&quot;horizontalRuler.jpg&quot;));<br>
              JLabel rowHeaderView = new JLabel(<br>
              new ImageIcon(&quot;verticalRuler.jpg&quot;));<br>
              JLabel view = new JLabel(<br>
              new ImageIcon(&quot;strawberry.jpg&quot;));</p>
            <p> JScrollPane sp = new JScrollPane(view);</p>
            <p> sp.setToolTipText(<br>
              &quot;Drag the headers to drag the picture!&quot;);</p>
            <p> HeaderViewDragListener verticalHeaderListener = <br>
              new HeaderViewDragListener(sp, <br>
              SwingConstants.VERTICAL);</p>
            <p> HeaderViewDragListener horizontalHeaderListener = <br>
              new HeaderViewDragListener(sp, <br>
              SwingConstants.HORIZONTAL);</p>
            <p> columnHeaderViewport.addMouseListener(<br>
              horizontalHeaderListener);<br>
              columnHeaderViewport.addMouseMotionListener(<br>
              horizontalHeaderListener);</p>
            <p> rowHeaderViewport.addMouseListener(<br>
              verticalHeaderListener);<br>
              rowHeaderViewport.addMouseMotionListener(<br>
              verticalHeaderListener);</p>
            <p> // headers must be set before header views<br>
              sp.setColumnHeader(columnHeaderViewport);<br>
              sp.setRowHeader(rowHeaderViewport);</p>
            <p> sp.setColumnHeaderView(columnHeaderView);<br>
              sp.setRowHeaderView(rowHeaderView);</p>
            <p> contentPane.add(sp);<br>
              }<br>
              }<br>
              class HeaderViewDragListener extends MouseAdapter<br>
              implements MouseMotionListener,<br>
              SwingConstants {<br>
              private Point last = new Point();<br>
              private JScrollPane scrollpane; <br>
              private int orientation;</p>
            <p> public HeaderViewDragListener(JScrollPane sp, int orient) {<br>
              scrollpane = sp;<br>
              orientation = orient;<br>
              }<br>
              public void mousePressed(MouseEvent e) {<br>
              last.x = e.getPoint().x;<br>
              last.y = e.getPoint().y;<br>
              }<br>
              public void mouseMoved(MouseEvent e) {<br>
              }<br>
              public void mouseDragged(MouseEvent e) {<br>
              JViewport headerViewport = (JViewport)e.getSource();<br>
              JViewport scrollpaneViewport = scrollpane.getViewport();<br>
              Dimension viewSize = scrollpaneViewport.getViewSize(),<br>
              extent = scrollpaneViewport.getExtentSize();</p>
            <p> Point drag = e.getPoint();<br>
              Point offset = new Point(drag.x-last.x, drag.y-last.y);<br>
              Point headerPosition = new Point(), viewportPosition;</p>
            <p> viewportPosition = scrollpaneViewport.getViewPosition();</p>
            <p> if(orientation == HORIZONTAL) {<br>
              int nextX = viewportPosition.x - offset.x;<br>
              int rightEdge = extent.width + nextX;</p>
            <p> if(nextX &gt; 0 &amp;&amp; rightEdge &lt; viewSize.width) {<br>
              headerPosition.x = nextX;<br>
              viewportPosition.x = nextX;<br>
              }<br>
              }<br>
              if(orientation == VERTICAL) { <br>
              int nextY = viewportPosition.y - offset.y;<br>
              int bottomEdge = extent.height + nextY;</p>
            <p> if(nextY &gt; 0 &amp;&amp; bottomEdge &lt; viewSize.height) {<br>
              headerPosition.y = nextY;<br>
              viewportPosition.y = nextY;<br>
              }<br>
              }<br>
              headerViewport.setViewPosition(headerPosition);<br>
              scrollpaneViewport.setViewPosition(viewportPosition);</p>
            <p> last.x = drag.x;<br>
              last.y = drag.y;<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p>&nbsp;</p>
            <p> 13.2.2 滚动窗的角部</p>
            <p>&nbsp;</p>
            <p align="center"><b>例13-8 指定滚动窗格的角部的组件</b></p>
            <hr noshade size="1">
            import java.awt.*;<br>
            import javax.swing.*;<br>
            import javax.swing.border.*;
            <p>public class Test extends JApplet {<br>
              public Test() {<br>
              Container contentPane = getContentPane();<br>
              JLabel columnHeaderView = new JLabel(<br>
              new ImageIcon(&quot;horizontalRuler.jpg&quot;));<br>
              JLabel rowHeaderView = new JLabel(<br>
              new ImageIcon(&quot;verticalRuler.jpg&quot;));<br>
              JLabel view = new JLabel(<br>
              new ImageIcon(&quot;anjinAndMariko.gif&quot;));</p>
            <p> JScrollPane sp = new JScrollPane(view);</p>
            <p> JPanel corners[] = {<br>
              new JPanel(), new JPanel(),<br>
              new JPanel(), new JPanel()<br>
              };<br>
              String cornerConstants[] = {<br>
              ScrollPaneConstants.UPPER_LEFT_CORNER,<br>
              ScrollPaneConstants.LOWER_LEFT_CORNER,<br>
              ScrollPaneConstants.UPPER_RIGHT_CORNER,<br>
              ScrollPaneConstants.LOWER_RIGHT_CORNER,<br>
              };<br>
              Border border = BorderFactory.createEtchedBorder();</p>
            <p> for(int i=0; i &lt; corners.length; ++i) {<br>
              corners[i].setBorder(border);<br>
              sp.setCorner(cornerConstants[i], corners[i]);<br>
              }</p>
            <p> sp.setColumnHeaderView(columnHeaderView);<br>
              sp.setRowHeaderView(rowHeaderView);<br>
              contentPane.add(sp);<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p> 13.2.3 JViewport属性</p>
            <p>&nbsp;</p>
            <p> 13.2.4 JViewport事件</p>
            <p>&nbsp;</p>
            <p> 13.2.5 JViewport类总结</p>
            <p>&nbsp;</p>
            <p align="center"><b>例13-9 透明和不透明滚动窗格</b></p>
            <hr noshade size="1">
            import java.awt.*;<br>
            import java.awt.event.*;<br>
            import javax.swing.*;
            <p>public class Test extends JApplet {<br>
              public void init() {<br>
              Container contentPane = new CustomContentPane();<br>