已知类MyClass中事件MouseClicked定义如下:public delegate void mydelegate(); public event mydelegate MouseClicked; 执行下列语句:Method obj = new Method(); MyClass e = new MyClass(); e.MouseClicked += obj.fun; e.MouseClicked += obj.fun; 其中Method类中包含事件处理方法fun。然后引发该MouseClicked事件,其结果为()。
A、obj.fun方法被调用4次
B、obj.fun方法被调用2次
C、obj.fun方法被调用1次
D、obj.fun方法不会被调用
第1题
第2题
A、publicclassMouseClickHandlerimplementsMouseAdapter
B、publicclassMouseClickHandlerextendsMouseAdapter
C、publicclassMouseClickHandlerimplementsMouseListener
D、publicclassMouseClickHandlerextendsMouseListener
第3题
第4题
注意:不改动程序的结构,不得增行或删行。
程序的执行结果为:
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
/*
<applet code=Hua width=200 height=100>
</applet>
*/
public class Hua extends Applet
{
int xPos,yPos;
int sum;
Image pic;
public void init()
{
addMouseListener(new ClickMouse());
}
public void paint(Graphics g)
{
if(sum==2)
{
g.drawImage(pic,xPos,yPos,200,180,super);
}
}
public class ClickMouse extends MouseAdapter
{
public void mouseClicked (MouseEvent mouse)
{
sum=mouse.getClickCount();
if(sum==2)
{
pic=getImage(getAudioClip(),"hua.jpg");
xPos=mouse.getX();
yPos=mouse.getY ( );
showStatus ("鼠标单击点的坐标: ("+mouse. getX ( ) +" , "+mouse. getY ( ) + ")" );
}
paint ( );
}
}
}
ex37_3.html:
<html>
<head>
<title>A Simple Program</title>
</head>
<body>
<applet code=" Hua.class" width=800 height=400>
</applet>
</body>
</html>
第5题
A、mouseClicked(MouseEvent)
B、mouseClicked(MouseEvent)mousePressed(MouseEvent)mouseReleased(MouseEvent)
C、mouseClicked(MouseEvent)mousePressed(MouseEvent)mouseReleased(MouseEvent)mouseEntered(MouseEvent)
D、mouseClicked(MouseEvent)mousePressed(MouseEvent)
第6题
注意:不改动程序的结构,不是增行或删行。
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class Example3_1 extends Applet
{
int xPoint, yPoint;
int sum;
Image displayIm;
public void init()
{
displayIm = getImage("ms.jpg");
addMouseListener(new SClickMouse()) ;
sum = 2;
}
public void paint(Graphics g)
{
if(sum == 1)
g.drawImage(displayIm, xPoint, yPoint, this);
else
g.fillRect(xPoint, yPoint, 60, 60);
}
public class SClickMouse implements MouseListener
{
public void mouseClicked(MouseEvent mouse)
{
sum = mouse.getClickCount();
xPoint = mouse.getX();
yPoint = mouse.getY();
paint();
}
public void mouseEntered(MouseEvent mouse)
{
}
public void mouseExited(MouseEvent mouse)
{}
public void mousePressed(MouseEvent mouse)
{
xPoint = mouse.getX();
yPoint = mouse.getY();
showStatus("x="+xPoint+",y-"+yPoint);
}
public void mouseReleased(MouseEvent mouse)
}
}
}
}
Exampie3_1.html:
<html>
<head><title>Example3_1</title></head>
<body>
<applet code="Example3_1.class" width="400" height="500">
</applet>
</body>
</html>
第7题
A、ActionListener
B、ItemListener
C、MouseMotionListener
D、MouseListener
第8题
第9题
第10题
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