s04.htm

Java2Swingt界面设计

            <p>&nbsp;</p>
            <p align="center"><b>例4-21 用客户属性把一个动态目标分配给一个按钮</b></p>
            <hr size="1" noshade>
            import javax.swing.*;<br>
            import java.util.*;<br>
            import java.awt.*;<br>
            import java.awt.event.*;<br>
            import java.beans.*;
            <p>public class ClientPropertiesTest extends JApplet {<br>
              JButton button = new JButton(&quot;toggle target color&quot;);<br>
              JComboBox targetCombo = new JComboBox();<br>
              JPanel[] targets = { new JPanel(),<br>
              new JPanel(),<br>
              new JPanel() };<br>
              public void init() {<br>
              Container contentPane = getContentPane();<br>
              Dimension targetPreferredSize = new Dimension(100,100);<br>
              JPanel targetPanel = new JPanel();</p>
            <p> for(int i=0; i &lt; targets.length; ++i) {<br>
              targets[i].setBackground(Color.blue);<br>
              targets[i].setPreferredSize(targetPreferredSize);<br>
              targetPanel.add(targets[i]);</p>
            <p> }<br>
              targetCombo.addItem(&quot;left&quot;);<br>
              targetCombo.addItem(&quot;center&quot;);<br>
              targetCombo.addItem(&quot;right&quot;);</p>
            <p> contentPane.setLayout(new FlowLayout());<br>
              contentPane.add(button);<br>
              contentPane.add(targetCombo);<br>
              contentPane.add(targetPanel);</p>
            <p> button.putClientProperty(&quot;target&quot;, targets[0]);</p>
            <p> button.addActionListener(new ActionListener() {<br>
              public void actionPerformed(ActionEvent e) {<br>
              Component c = <br>
              (Component)button.getClientProperty(&quot;target&quot;);</p>
            <p> if(c != null) {<br>
              Color bg = c.getBackground();</p>
            <p> c.setBackground(bg == Color.blue ?<br>
              Color.red : Color.blue);</p>
            <p> c.repaint();<br>
              }<br>
              }<br>
              });<br>
              targetCombo.addActionListener(new ActionListener() {<br>
              public void actionPerformed(ActionEvent e) {<br>
              button.putClientProperty(<br>
              &quot;target&quot;, <br>
              targets[targetCombo.getSelectedIndex()]);<br>
              }<br>
              });<br>
              button.addPropertyChangeListener(<br>
              new PropertyChangeListener() {<br>
              public void propertyChange(PropertyChangeEvent e) {<br>
              if(e.getPropertyName().equals(&quot;target&quot;)) {<br>
              showStatus(<br>
              (String)targetCombo.getSelectedItem() + <br>
              &quot; panel set as target&quot;);<br>
              }<br>
              }<br>
              });<br>
              }<br>
              public static void main(String args[]) {<br>
              final JFrame f = new JFrame();<br>
              JApplet applet = new ClientPropertiesTest();</p>
            <p> applet.init();</p>
            <p> f.setContentPane(applet.getContentPane());<br>
              f.setBounds(100,100,300,250);<br>
              f.setTitle(&quot;ClientPropertiesTest&quot;);<br>
              f.setVisible(true);</p>
            <p> f.addWindowListener(new WindowAdapter() {<br>
              public void windowClosing(WindowEvent e) {<br>
              f.dispose();<br>
              System.exit(0);<br>
              }<br>
              });<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p> 4.10 焦点管理</p>
            <p>&nbsp;</p>
            <p> 4.10.1 JComponent的焦点属性</p>
            <p>&nbsp;</p>
            <p align="center"><b>例4-22 为Swing组件指定焦点属性</b></p>
            <hr size="1" noshade>
            import javax.swing.*;<br>
            import java.awt.*;<br>
            import java.awt.event.*;
            <p>public class Test extends JApplet {<br>
              private JButton button_1 = new NotFocusTraversableButton(),<br>
              button_2 = new ButtonThatManagesFocus(),<br>
              button_3 = new JButton(&quot;regular button&quot;),<br>
              button_4 = new JButton(&quot;regular button&quot;),<br>
              button_5 = new JButton(&quot;request focus disabled&quot;),<br>
              button_6 = new JButton(<br>
              &quot;next focusable component set to Manages Focus button&quot;);</p>
            <p> public void init() {<br>
              Container contentPane = getContentPane();<br>
              FocusCycleRootPanel panel = new FocusCycleRootPanel();</p>
            <p> button_5.setRequestFocusEnabled(false);<br>
              button_6.setNextFocusableComponent(button_2);</p>
            <p> panel.add(button_3);<br>
              panel.add(button_4);<br>
              panel.add(button_5);</p>
            <p> contentPane.setLayout(new FlowLayout());<br>
              contentPane.add(button_1);<br>
              contentPane.add(button_2);<br>
              contentPane.add(panel);<br>
              contentPane.add(button_6);<br>
              }<br>
              }<br>
              class ButtonThatManagesFocus extends JButton {<br>
              public ButtonThatManagesFocus() {<br>
              super(&quot;Manages Focus&quot;); <br>
              }<br>
              public boolean isManagingFocus() {<br>
              return true;<br>
              }<br>
              public void processComponentKeyEvent(KeyEvent e) {<br>
              System.out.println(e);<br>
              }<br>
              }<br>
              class NotFocusTraversableButton extends JButton {<br>
              public NotFocusTraversableButton() {<br>
              super(&quot;Not Focus Traversable&quot;); <br>
              }<br>
              public boolean isFocusTraversable() {<br>
              return false;<br>
              }<br>
              }<br>
              class FocusCycleRootPanel extends JPanel {<br>
              public FocusCycleRootPanel() {<br>
              setBorder(BorderFactory.createTitledBorder(<br>
              &quot;FocusCycleRoot Panel&quot;));<br>
              }<br>
              public boolean isFocusCycleRoot() {<br>
              return true;<br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p> 4.10.2 焦点管理器</p>
            <p>&nbsp;</p>
            <p align="center"><b>例4-23 实现一个定制的焦点管理器</b></p>
            <hr size="1" noshade>
            import javax.swing.*;<br>
            import java.awt.*;<br>
            import java.awt.event.*;
            <p>public class Test extends JApplet {<br>
              private JButton button_1 = new JButton(&quot;button one&quot;),<br>
              button_2 = new JButton(&quot;button two&quot;),<br>
              button_3 = new JButton(&quot;button three&quot;),<br>
              button_4 = new JButton(&quot;button four&quot;),<br>
              button_5 = new JButton(&quot;button five&quot;),<br>
              button_6 = new JButton(&quot;button six&quot;);</p>
            <p> public void init() {<br>
              Container contentPane = getContentPane();</p>
            <p> javax.swing.FocusManager.setCurrentManager(<br>
              new CustomFocusManager());</p>
            <p> contentPane.setLayout(new FlowLayout());<br>
              contentPane.add(button_1);<br>
              contentPane.add(button_2);<br>
              contentPane.add(button_3);<br>
              contentPane.add(button_4);<br>
              contentPane.add(button_5);<br>
              contentPane.add(button_6);<br>
              }<br>
              }<br>
              class CustomFocusManager extends DefaultFocusManager {<br>
              public boolean compareTabOrder(Component a, Component b) {<br>
              Point location_a = a.getLocation(),<br>
              location_b = b.getLocation();</p>
            <p> int ax = location_a.x, ay = location_a.y;<br>
              int bx = location_b.x, by = location_b.y;</p>
            <p> if(Math.abs(ay - by) &lt; 10) {<br>
              return (bx &lt; ax);<br>
              }<br>
              return (ay &gt; by); <br>
              }<br>
              }</p>
            <hr size="1" noshade>
            <p> 4.11 支持可访问性</p>
            <p>&nbsp;</p>
            <p align="center"><b>例4-24 获得可访问性信息</b></p>
            <hr size="1" noshade>
            import javax.swing.*;<br>
            import javax.accessibility.*;<br>
            import java.awt.*;<br>
            import java.awt.event.*;
            <p>public class Test extends JApplet {<br>
              public void init() {<br>
              Container contentPane = getContentPane();<br>
              JLabel label = new JLabel(&quot;First Name:&quot;);<br>
              JButton showButton = new JButton(<br>
              &quot;show accessible information&quot;);</p>
            <p> final JTextField field = new JTextField(15);</p>
            <p> AccessibleContext fieldContext = <br>
              field.getAccessibleContext();</p>
            <p> fieldContext.setAccessibleName(&quot;First Name&quot;);<br>
              fieldContext.setAccessibleDescription(<br>
              &quot;Enter your first name&quot;);</p>
            <p> contentPane.setLayout(new FlowLayout());<br>
              contentPane.add(showButton);<br>
              contentPane.add(label);<br>
              contentPane.add(field);</p>
            <p> showButton.addActionListener(new ActionListener() {<br>
              public void actionPerformed(ActionEvent e) {<br>
              AccessibleContext context;<br>
              AccessibleRole role;</p>
            <p> context = field.getAccessibleContext();<br>
              role = context.getAccessibleRole();</p>
            <p> System.out.print(&quot;Accessible Role: &quot;);<br>
              System.out.println(<br>
              context.getAccessibleRole());</p>
            <p> System.out.print(&quot;Accessible Description: &quot;);<br>
              System.out.println(<br>
              context.getAccessibleDescription());</p>
            <p> System.out.print(&quot;Accessible Name: &quot;);<br>
              System.out.println(<br>
              context.getAccessibleName());<br>
              <br>
              }<br>
              });</p>
            <p> }<br>
              }</p>
            <hr size="1" noshade>
            <p> 4.12 本章回顾</p>
            <p>&nbsp;</p>
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