8.事件处理

loadButton.addActionListener(
<span style="white-space:pre"> </span>EventHandler.create(ActionListener.class, frame, "loadData"));

java.beans.EventHandler 1.4

• static Object create(Class listenerInterface, Object target, String

action)

• static Object create(Class listenerInterface, Object target, String

action, String eventProperty)

• static Object create(Class listenerInterface, Object target, String
action, String eventProperty, String listenerMethod)

改变观感

jre/lib目录下的swing.properties              swing.defaultlaf=com.sun.java.swing.plaf.motif.MotifLookAndFeel
UIManager.setLookAndFeel       SwingUtilities.updateComponentTreeUI

String plaf = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";
try
{
<span style="white-space:pre">	</span>UIManager.setLookAndFeel(plaf);
<span style="white-space:pre">	</span>SwingUtilities.updateComponentTreeUI(panel);
}
catch(Exception e) { e.printStackTrace(); }

UIManager.LookAndFeelInfo[] infos = UIManager.getInstalledLookAndFeels();

String name = infos[i].getName();

String className = infos[i].getClassName();

外部对象的this指针必须将外部类名作为前缀

javax.swing.UIManager 1.2

javax.swing.UIManager.LookAndFeelInfo 1.2

适配器类

WindowListener listener = . . .;

frame.addWindowListener(listener);

public interface WindowListener

{
void windowOpened(WindowEvent e);
void windowClosing(WindowEvent e);
void windowClosed(WindowEvent e);
void windowIconified(WindowEvent e);
void windowDeiconified(WindowEvent e);
void windowActivated(WindowEvent e);
void windowDeactivated(WindowEvent e);

}

WindowAdapter是对WindowListener的空实现；

frame.addWindowListener(new WindowAdapter()
<span style="white-space:pre">	</span>{
<span style="white-space:pre">		</span>public void windowClosing(WindowEvent e)
<span style="white-space:pre">		</span>{
<span style="white-space:pre">			</span>if (user agrees)
<span style="white-space:pre">			</span>System.exit(0);
<span style="white-space:pre">		</span>}
});

java.awt.event.WindowStateListener 1.4

• void windowStateChanged(WindowEvent event)

java.awt.event.WindowEvent 1.1

• int getNewState() 1.4

• int getOldState() 1.4

动作

The Action interface has the following methods:    //扩展了ActionListener

void actionPerformed(ActionEvent event)

void setEnabled(boolean b)

boolean isEnabled()

void putValue(String key, Object value)

Object getValue(String key)

void addPropertyChangeListener(PropertyChangeListener listener)

void removePropertyChangeListener(PropertyChangeListener listener)

AbstractAction 实现了除actionPerformed外的所有方法

处理按键时，与focus 有关

每个JComponent有三个输入映射

/**
* A frame with a panel that demonstrates color change actions.
*/
public class ActionFrame extends JFrame
{
private JPanel buttonPanel;
private static final int DEFAULT_WIDTH = 300;
private static final int DEFAULT_HEIGHT = 200;

public ActionFrame()
{
setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

buttonPanel = new JPanel();

// define actions
Action yellowAction = new ColorAction("Yellow", new ImageIcon("yellow-ball.gif"),
Color.YELLOW);
Action blueAction = new ColorAction("Blue", new ImageIcon("blue-ball.gif"), Color.BLUE);
Action redAction = new ColorAction("Red", new ImageIcon("red-ball.gif"), Color.RED);

// add buttons for these actions
buttonPanel.add(new JButton(yellowAction));
buttonPanel.add(new JButton(blueAction));
buttonPanel.add(new JButton(redAction));

// add panel to frame
add(buttonPanel);

// associate the Y, B, and R keys with names
InputMap imap = buttonPanel.getInputMap(JComponent.WHEN_ANCESTOR_OF_FOCUSED_COMPONENT);
imap.put(KeyStroke.getKeyStroke("ctrl Y"), "panel.yellow");
imap.put(KeyStroke.getKeyStroke("ctrl B"), "panel.blue");
imap.put(KeyStroke.getKeyStroke("ctrl R"), "panel.red");

// associate the names with actions
ActionMap amap = buttonPanel.getActionMap();
amap.put("panel.yellow", yellowAction);
amap.put("panel.b
4000
lue", blueAction);
amap.put("panel.red", redAction);
}

public class ColorAction extends AbstractAction
{
/**
* Constructs a color action.
* @param name the name to show on the button
* @param icon the icon to display on the button
* @param c the background color
*/
public ColorAction(String name, Icon icon, Color c)
{
putValue(Action.NAME, name);
putValue(Action.SMALL_ICON, icon);
putValue(Action.SHORT_DESCRIPTION, "Set panel color to " + name.toLowerCase());
putValue("color", c);
}

public void actionPerformed(ActionEvent event)
{
Color c = (Color) getValue("color");
buttonPanel.setBackground(c);
}
}
}

javax.swing.JComponent 1.2

• ActionMap getActionMap() 1.3

returns the map that associates action map keys (which can be arbitrary

objects) with Action objects.

• InputMap getInputMap(int flag)1.3

gets the input map that maps key strokes to action map keys.

鼠标事件

java.awt.event.InputEvent 1.1

• int getModifiersEx() 1.4

returns the extended or “down” modifiers for this event. Use the following

mask values to test the returned value:

BUTTON1_DOWN_MASK

BUTTON2_DOWN_MASK

BUTTON3_DOWN_MASK

SHIFT_DOWN_MASK

CTRL_DOWN_MASK

ALT_DOWN_MASK

ALT_GRAPH_DOWN_MASK

META_DOWN_MASK

• static String getModifiersExText(int modifiers) 1.4

returns a string such as "Shift+Button1" describing the extended or “down”

modifiers in the given flag set.

AWT事件继承层次

所有事件有 util 包中的EventObject类扩展而来