Import java.awt.*
import java.awt.event.*;
import javax.swing.*;
class EventQueuePanel extends JPanel implements Ac-
tionListener
{EventQueuePanel()
{JButton button=new JButton("Draw line");
add(button);
button.addActionListener(this);
}
public void actionPerformed(ActionEvent evt)
(Graphics g=getGraphics();
P=getClick();
g.drawOval(P.x-2,P.Y-2,4,4);
Point q=getClick();
g.drawOval(q.x-2,q.y-2,4,4);
g.drawLine(P.X,P.Y,q.x,q.y);
g.dispose();
}
public Point getClick()
{EventQueue eq=Toolkit.getDefaultToolkit().
getSystemEventQueue();
while(true)
{try
{AWTEvent evt=eq.getNextEvent();
if(evt.getID()= =MouseEvent.MOUSE.
PRESSED)
{MouseEvent mevt=(MouseEvent)evt;
Point P= ();
Point top=getRootPane().getLocation();
P.X-=top.x;
P.Y-=top.Y;
return P;
}
}
catch(InterruptedException e)
{}
}
}
private int Y=60;
}
class EventQueueFrame. extends JFrame
{public EventQueueFrame()
{setTitle("java2");
setSize(300,200);
addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{System.exit(0);
}
});
Container contentPane=getContentPane();
contentPane.add(new EventQueuePanel());
}
}
public class java2
{public static void main(String[]args)
{Frame. frame=new EventQueueFrame();
frame.show();
}
}
A.只画出材料的图例
B.不画材料图例
C.画倾斜的直线
D.只用文字说明材料的名称
在窗口中直接键入?HOUR({^2003-01-0204:59:23PM}),则结果为______。
A.04
B.16
C.59
D.23
A.LINE所画的线相当于由PLINE画的宽度等于0的线
B.LINE命令后不仅能输入点的坐标,而且能输入文字如U等
C.LINE命令后可以使用如点的捕捉、正交模式等辅助命令
D.LINE命令可以绘制轴测图
在Visual:Basic的立即窗口内输入以下语句: X=65 <CR> Print Chr$(x) <CR> 在窗口中显示的结果是
A.65
B.A
C.a
D.x