s12.htm

java图形设计卷2 swing

            <p>&nbsp;</p>
            <p> 12.3.1 回顾轻量组件的层序</p>
            <p>&nbsp;</p>
            <p align="center"><b>例12-5 添加到一个内容窗格中的按钮的程序</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>
              Container cp = getContentPane();</p>
            <p> private final Component[] comps = {<br>
              new JButton(), new JButton(), <br>
              new JButton(), new JButton(), <br>
              new JButton(), new JButton(), <br>
              };<br>
              public void init() {<br>
              cp.setLayout(null);</p>
            <p> for(int i=0; i &lt; comps.length; ++i) {<br>
              AbstractButton button = (AbstractButton)comps[i];<br>
              cp.add(button);</p>
            <p> String t = &quot;Button #&quot;;</p>
            <p> t += i + &quot; Index: &quot; + getIndexOf(button);</p>
            <p> button.setText(t);<br>
              button.setBounds(i*50, i*50, 350, 75);<br>
              System.out.println(&quot;Adding: &quot; + button.getText());<br>
              }<br>
              }<br>
              private int getIndexOf(Component button) {<br>
              int ncomponents = cp.getComponentCount();</p>
            <p> for(int i=0; i &lt; ncomponents; ++i) {<br>
              Component c = cp.getComponent(i);<br>
              if(button == c)<br>
              return i;<br>
              }<br>
              return -1;<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p align="center">&nbsp;</p>
            <p> 12.3.2 为组件分配器</p>
            <p>&nbsp;</p>
            <p align="center"><b>例12-6 所包含在一个分层窗格中的组件分配到层中</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>
              private JLayeredPane lp = new JLayeredPane();</p>
            <p> private Integer[] layers = {<br>
              JLayeredPane.FRAME_CONTENT_LAYER,<br>
              JLayeredPane.DEFAULT_LAYER,<br>
              JLayeredPane.PALETTE_LAYER,<br>
              JLayeredPane.MODAL_LAYER,<br>
              JLayeredPane.POPUP_LAYER,<br>
              JLayeredPane.DRAG_LAYER,<br>
              };<br>
              private final Component[] comps = {<br>
              new JButton(&quot;Frame Content&quot;), new JButton(&quot;Default&quot;), 
              <br>
              new JButton(&quot;Palette&quot;), new JButton(&quot;Modal&quot;), 
              <br>
              new JButton(&quot;Popup&quot;), new JButton(&quot;Drag&quot;), <br>
              };<br>
              public void init() {<br>
              setContentPane(lp);<br>
              lp.setLayout(null);</p>
            <p> for(int i=0; i &lt; comps.length; ++i) {<br>
              AbstractButton button = (AbstractButton)comps[i];</p>
            <p> System.out.println(&quot;Adding: &quot; + button.getText());</p>
            <p> lp.setLayer(button, layers[i].intValue());<br>
              lp.add(button);<br>
              }<br>
              for(int i=0; i &lt; comps.length; ++i) {<br>
              AbstractButton button = (AbstractButton)comps[i];<br>
              String t = button.getText();<br>
              String replacement = new String(&quot;Layer: &quot;);</p>
            <p> replacement += t + &quot;(&quot; + lp.getLayer(button) + &quot;),&quot;;<br>
              replacement += &quot; Index: &quot; + lp.getIndexOf(button);</p>
            <p> button.setText(replacement);<br>
              button.setBounds(i*50, i*50, 350, 75); <br>
              }<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p>&nbsp;</p>
            <p> 12.3.3 指定同一层中组件的位置</p>
            <p>&nbsp;</p>
            <p align="center"><b>例12-7 同一层中放置组件的缺省方式</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>
              private JLayeredPane lp = new JLayeredPane();</p>
            <p> private Integer[] layers = {<br>
              JLayeredPane.FRAME_CONTENT_LAYER,<br>
              JLayeredPane.DEFAULT_LAYER,<br>
              JLayeredPane.DEFAULT_LAYER,<br>
              JLayeredPane.DEFAULT_LAYER,<br>
              JLayeredPane.PALETTE_LAYER,<br>
              JLayeredPane.MODAL_LAYER,<br>
              JLayeredPane.POPUP_LAYER,<br>
              JLayeredPane.DRAG_LAYER,<br>
              };<br>
              private final Component[] comps = {<br>
              new JButton(&quot;Frame Content&quot;), new JButton(&quot;Default&quot;), 
              <br>
              new JButton(&quot;default 1&quot;), new JButton(&quot;default 2&quot;), 
              <br>
              new JButton(&quot;Palette&quot;), new JButton(&quot;Modal&quot;), 
              <br>
              new JButton(&quot;Popup&quot;), new JButton(&quot;Drag&quot;), <br>
              };<br>
              public void init() {<br>
              setContentPane(lp);<br>
              lp.setLayout(null);</p>
            <p> for(int i=0; i &lt; comps.length; ++i) {<br>
              AbstractButton button = (AbstractButton)comps[i];</p>
            <p> lp.setLayer(button, layers[i].intValue());<br>
              lp.add(button);<br>
              }<br>
              for(int i=0; i &lt; comps.length; ++i) {<br>
              AbstractButton button = (AbstractButton)comps[i];<br>
              String t = button.getText();<br>
              String replacement = new String(&quot;Layer: &quot;);</p>
            <p> replacement += t + &quot;(&quot; + lp.getLayer(button) + &quot;),&quot;;<br>
              replacement += &quot; Index: &quot; + lp.getIndexOf(button);<br>
              replacement += &quot; Position: &quot; + <br>
              lp.getPosition(button);</p>
            <p> button.setText(replacement);<br>
              button.setBounds(i*50, i*50, 350, 75); <br>
              }<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p align="center"><b>例12-8 显式地设置同层中组件的位置</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>
              private JLayeredPane lp = new JLayeredPane();</p>
            <p> private Integer[] layers = {<br>
              JLayeredPane.FRAME_CONTENT_LAYER,<br>
              JLayeredPane.DEFAULT_LAYER,<br>
              JLayeredPane.DEFAULT_LAYER,<br>
              JLayeredPane.DEFAULT_LAYER,<br>
              JLayeredPane.PALETTE_LAYER,<br>
              JLayeredPane.MODAL_LAYER,<br>
              JLayeredPane.POPUP_LAYER,<br>
              JLayeredPane.DRAG_LAYER,<br>
              };<br>
              private final Component[] comps = {<br>
              new JButton(&quot;Frame Content&quot;), new JButton(&quot;Default&quot;), 
              <br>
              new JButton(&quot;default 1&quot;), new JButton(&quot;default 2&quot;), 
              <br>
              new JButton(&quot;Palette&quot;), new JButton(&quot;Modal&quot;), 
              <br>
              new JButton(&quot;Popup&quot;), new JButton(&quot;Drag&quot;), <br>
              };<br>
              public void init() {<br>
              setContentPane(lp);<br>
              lp.setLayout(null);</p>
            <p> for(int i=0; i &lt; comps.length; ++i) {<br>
              AbstractButton button = (AbstractButton)comps[i];<br>
              String t = button.getText();</p>
            <p> lp.setLayer(button, layers[i].intValue());<br>
              lp.add(button);<br>
              }<br>
              for(int i=0; i &lt; comps.length; ++i) {<br>
              AbstractButton button = (AbstractButton)comps[i];<br>
              String t = button.getText();<br>
              String replacement = new String(&quot;Layer: &quot;);</p>
            <p> if(t.equals(&quot;Default&quot;))<br>
              lp.setPosition(button, 2); <br>
              else if(t.equals(&quot;default 2&quot;))<br>
              lp.setPosition(button, 0); </p>
            <p> replacement += t + &quot;(&quot; + lp.getLayer(button) + &quot;),&quot;;<br>
              replacement += &quot; Index: &quot; + lp.getIndexOf(button);<br>
              replacement += &quot; Position: &quot; + <br>
              lp.getPosition(button);</p>
            <p> button.setText(replacement);<br>
              button.setBounds(i*50, i*50, 350, 75); <br>
              }<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p>&nbsp;</p>
            <p>&nbsp;</p>
            <p> 12.3.4 使用拖动层</p>
            <p>&nbsp;</p>
            <p align="center"><b>例12-9 使用拖动层</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>
              setContentPane(new CustomContentPane());<br>
              }<br>
              }<br>
              class CustomContentPane extends JLayeredPane {<br>
              private ImageIcon rain = new ImageIcon(&quot;rain.gif&quot;);<br>
              private ImageIcon punch = new ImageIcon(&quot;punch.gif&quot;);<br>
              private ImageIcon skelly = new ImageIcon(&quot;skelly.gif&quot;);<br>
              private int rainw = rain.getIconWidth();<br>
              private int rainh = rain.getIconHeight();</p>
            <p> private JLabel[] labels = { <br>
              new JLabel(&quot;I stay put&quot;, punch, SwingConstants.RIGHT),<br>
              new JLabel(&quot;Drag me around!&quot;, <br>
              skelly, SwingConstants.RIGHT),<br>
              };</p>
            <p> public CustomContentPane() {<br>
              Dragger listener = new Dragger();<br>
              JCheckBox onDragLayer = new JCheckBox(&quot;Drag Layer&quot;);</p>
            <p> // JLayeredPane has a null layout by default<br>
              setLayout(new FlowLayout());</p>
            <p> onDragLayer.setOpaque(false);</p>
            <p> add(onDragLayer);<br>
              add(labels[0]);<br>
              add(labels[1]);</p>
            <p> labels[1].addMouseMotionListener(listener);<br>
              labels[1].addMouseListener(listener);</p>
            <p> setLabelText();</p>
            <p> onDragLayer.addItemListener(new ItemListener() {<br>
              public void itemStateChanged(ItemEvent e) {<br>
              if(e.getStateChange() == ItemEvent.SELECTED) {<br>
              setLayer(labels[1], <br>
              JLayeredPane.DRAG_LAYER.intValue());<br>
              }<br>
              else {<br>
              setLayer(labels[1], <br>
              JLayeredPane.DEFAULT_LAYER.intValue());<br>
              <br>
              }<br>
              setLabelText();<br>
              validate();<br>
              }<br>
              });<br>
              }<br>
              public void paintComponent(Graphics g) {<br>
              Dimension size = getSize();</p>
            <p> for(int row=0; row &lt; size.height; row += rainh)<br>
              for(int col=0; col &lt; size.width; col += rainw)<br>
              rain.paintIcon(this,g,col,row);<br>
              }<br>
              private void setLabelText() {<br>
              for(int i=0; i &lt; labels.length; ++i) {<br>
              JLabel label = labels[i];<br>
              String t = new String(&quot;Layer: &quot;);</p>
            <p> t += &quot;(&quot; + getLayer(label) + &quot;),&quot;;<br>
              t += &quot; Index: &quot; + getIndexOf(label);</p>
            <p> label.setText(t);<br>
              }<br>
              }<br>
              }<br>
              class Dragger extends MouseAdapter <br>
              implements MouseMotionListener {<br>
              Point press = new Point();<br>
              boolean dragging = false;</p>
            <p> public void mousePressed(MouseEvent event) {<br>
              press.x = event.getX();<br>
              press.y = event.getY();<br>
              dragging = true;<br>
              }<br>
              public boolean isDragging() {<br>
              return dragging;<br>
              }<br>
              public void mouseReleased(MouseEvent event) {<br>
              dragging = false;<br>
              }<br>
              public void mouseClicked(MouseEvent event) {<br>
              dragging = false;<br>
              }<br>
              public void mouseMoved(MouseEvent event) {<br>
              // don't care<br>
              }<br>
              public void mouseDragged(MouseEvent event) {<br>
              Component c = (Component)event.getSource();</p>
            <p> if(dragging) {<br>
              Point loc = c.getLocation();<br>
              Point pt = new Point();<br>
              pt.x = event.getX() + loc.x - press.x;<br>
              pt.y = event.getY() + loc.y - press.y;<br>
              c.setLocation(pt.x, pt.y);<br>
              c.getParent().repaint();<br>
              }<br>