以下哪本书记载了对服食水银、雄黄、金石可以成仙之说的批评之语。()
A.《神农本草经》
B.《本草纲目》
C.《本经》
参考答案:B
简述一般性行业分类。
本题的功能是用键盘上的方向键来控制直线的绘制方向。如果一直按向上的方向键,则在窗口中从焦点开始向上缓慢绘制直线,按其他方向键也会向对应的方向缓慢地绘制直线,如果按下<Shift>键的话,绘制直线的速度会加快。 import java.awt.*; import java.awt.geom.*; import java.util.*; import java.awt.event.*; import javax.swing.*; public class java3 public static void main(String[]args) SketchFrame frame=new SketchFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.show(); class SketchFrame extends JFrame public SketchFrame() setTitle("java3"); setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT); SketchPanel panel=new SketchPanel(); Container contentPane=getContentPane(); contentPane.add(panel); public static final int DEFAULT_WIDTH=300; public static final int DEFAULT_HEIGHT=200; class SketchPanel extends JPanel public void sketchPanel() last=new Point2D.Double(100,100); lines=new ArrayList(); KeyHandler listener=new KeyHandler(); addkeyListener(this); setFocusable(true); public void add(int dx,int dy) Point2D end=new Point2D.Double(last.getX()+dx, last.getY()+dy); Line2D line=new Line2D.Double(last,end); lines.add(line); repaint(); last=end; public void paintComponent(Graphics g) super.paintComponent(g); Graphics2D g2=(Graphics2D)g; for(int i=0;i<lines.size();i++) g2.draw((Line2D)lines.get(i)); private Point2D last; private ArrayList lines; private static final int SMALL_INCREMENT=1; private static final int LARGE_INCREMENT=5; private class KeyHandler implements KeyListener public void keyPressed(KeyEvent event) KEY keyCode=event.getKeyCode(); int d; if (event isShiftDnwn ()) d=LARGE_INCREMENT; else d=SMALL_INCREMENT; if(keyCode==KeyEvent.VK_LEFT)add(-d,0); else if(keyCode==KeyEvent.VK_RIGHT)add(d,0); else if(keyCode==KeyEvent.VK_UP)add(0,-d); else if(keyCode==KeyEvent.VK_DOWN)add(0,d); public void keyReleased(KeyEvent event) public void keyTyped(KeyEvent event) char keyChar=event.getKeyChar(); int d; if(Character.isUpperCase(keyChar)) d=LARGE_INCREMENT; keyChar=Character.toLowerCase(keyChar); else d=SMALL_INCREMENT;