自己的以时间和4个像素的鼠标滞后作用的“mouseReallyClicked()真实的鼠标单击”方法。5. 蹩脚的组件继承另一种做法是调用enableEvent()方法，并将与希望控制的事件对应的模型传递给它（许多参考书中都曾提及这种做法）。这样做会造成那些事件被发送至老式方法（尽管它们对Java 1.1来说是新的），并采用象processFocusEvent()这样的名字。也必须要记住调用基础类版本。下面是它看起来的样子。
//: BadTechnique.java
// It''s possible to override components this way,
// but the listener approach is much better, so
// why would you?
import java.awt.*;
import java.awt.event.*;
class Display {
public static final int
EVENT = 0, COMPONENT = 1,
MOUSE = 2, MOUSE_MOVE = 3,
FOCUS = 4, KEY = 5, ACTION = 6,
LAST = 7;
public String[] evnt;
Display() {
evnt = new String[LAST];
for(int i = 0; i < LAST; i++)
evnt[i] = new String();
}
public void show(Graphics g) {
for(int i = 0; i < LAST; i++)
g.drawString(evnt[i], 0, 10 * i + 10);
}
}
class EnabledPanel extends Panel {
Color c;
int id;
Display display = new Display();
public EnabledPanel(int i, Color mc) {
id = i;
c = mc;
setLayout(new BorderLayout());
add(new MyButton(), BorderLayout.SOUTH);
// Type checking is lost. You can enable and
// process events that the component doesn''t
// capture:
enableEvents(
// Panel doesn''t handle these:
AWTEvent.ACTION_EVENT_MASK |
AWTEvent.ADJUSTMENT_EVENT_MASK |
AWTEvent.ITEM_EVENT_MASK |
AWTEvent.TEXT_EVENT_MASK |
AWTEvent.WINDOW_EVENT_MASK |
// Panel can handle these:
AWTEvent.COMPONENT_EVENT_MASK |
AWTEvent.FOCUS_EVENT_MASK |
AWTEvent.KEY_EVENT_MASK |
AWTEvent.MOUSE_EVENT_MASK |
AWTEvent.MOUSE_MOTION_EVENT_MASK |
AWTEvent.CONTAINER_EVENT_MASK);
// You can enable an event without
// overriding its process method.
}
// To eliminate flicker:
public void update(Graphics g) {
paint(g);
}
public void paint(Graphics g) {
g.setColor(c);
Dimension s = getSize();
g.fillRect(0, 0, s.width, s.height);
g.setColor(Color.black);
display.show(g);
}
public void processEvent(AWTEvent e) {
display.evnt[Display.EVENT]= e.toString();
repaint();
super.processEvent(e);
}
public void
processComponentEvent(ComponentEvent e) {
switch(e.getID()) {
case ComponentEvent.COMPONENT_MOVED:
display.evnt[Display.COMPONENT] =
"Component moved";
break;
case ComponentEvent.COMPONENT_RESIZED:
display.evnt[Display.COMPONENT] =
"Component resized";
break;
case ComponentEvent.COMPONENT_HIDDEN:
display.evnt[Display.COMPONENT] =
"Component hidden";
break;
case ComponentEvent.COMPONENT_SHOWN:
display.evnt[Display.COMPONENT] =
"Component shown";
break;
default:
}
repaint();
// Must always remember to call |
