a5_12.java

用JAVA实现控制面板上的字体特性 比如:控制字体大小,控制字体颜色.当然读者可以自己再依此补充 这是课后的一个习题的答案

/*<APPLET  Code="a5_12.class"
   Width=500    Height=500>
 </APPLET>*/
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class a5_12 extends Applet 
{
	Button bnred ;
	Button bnblue;
	Button bnsm;
	Button bnbg;
	private	canvas1  cv = new canvas1();
	public void init(){
		Panel panel=new Panel();
		bnred=new Button("red");
		bnblue=new Button("blue");
		bnbg=new Button("big");
		bnsm=new Button("small");
		panel.setLayout(new FlowLayout());
		panel.add(bnred);
		panel.add(bnblue);
		panel.add(bnbg);
		panel.add(bnsm);
		setLayout(new BorderLayout());
		add("Center",cv);
		add("North",panel);
		bnred.addActionListener(cv);
        bnblue.addActionListener(cv);
		bnbg.addActionListener(cv);
		bnsm.addActionListener(cv);
	}
	public class canvas1 extends Canvas implements ActionListener
	{  
		Color color=Color.BLACK;
	    int x=10;
	public void paint(Graphics g){
		g.setColor(color);
		g.setFont(new Font("Dialog",Font.BOLD,x));
		g.drawString("YES,YOU DO IT VERY WELL",30,30);
	}
    public void actionPerformed(ActionEvent e){
		if(e.getSource()==a5_12.this.bnblue)color=Color.blue;
		if(e.getSource()==a5_12.this.bnred)color=Color.red;
		if(e.getSource()==a5_12.this.bnbg)x+=10;
		if (e.getSource()==a5_12.this.bnsm)x-=10;
		if(x<10)x=10;
		if(x>100)x=100;
		repaint();
	}
	}
}