初学，Applet如何改变字体？头晕

Question

来先看段代码，其中有错误。import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.Button;
import java.awt.Graphics;
import java.awt.Panel;public class FontInApplet extends Applet implements ActionListener
{
private Button big = new Button("放大");
private Button small = new Button("缩小");
private String str = "this is my first applet program"; public void init(){
Panel panel = new Panel(new FlowLayout());
setLayout(new BorderLayout());
panel.add(big);
panel.add(small);
add(panel,BorderLayout.NORTH); big.addActionListener(this);
small.addActionListener(this); setSize(300,300);
setVisible(true);
} public void actionPerformed(ActionEvent e){
//Graphics g = new Graphics();
if(e.getSource()==big){
g.setFont(new Font(str,Font.PLAIN,14));
}
if(e.getSource()==small){
g.setFont(new Font(str,Font.PLAIN,10));
}
}
         public void paint(Graphics g){
                  g.drawString(str,150,150);
         }
}想了很多方法，但是都无法正确改变字体。还有，paint方法何时调用？不胜感激。

Answer 1

applet不是已经不太用了么，已经淡忘了

Answer 2

import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.Button;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Panel;public class Test extends Applet implements ActionListener
{
    private Button big = new Button("放大");
    private Button small = new Button("缩小");
    private String str = "this is my first applet program";    public void init(){
        Panel panel = new Panel(new FlowLayout());
        setLayout(new BorderLayout());
        panel.add(big);
        panel.add(small);
        add(panel,BorderLayout.NORTH);        big.addActionListener(this);
        small.addActionListener(this);        setSize(300,300);
        setVisible(true);
    }    public void actionPerformed(ActionEvent e){
        Graphics g = this.getGraphics();
        if(e.getSource()==big){
            this.setFont(new Font(str,Font.PLAIN,20));
            repaint();
        }
        if(e.getSource()==small){
            this.setFont(new Font(str,Font.PLAIN,10));
            repaint();
        }
    }
         public void paint(Graphics g){
                  g.drawString(str,150,150);
         }
}我看了下api，g.drawString 是用当前的字体，所以用this.setFont(),可以啦

Answer 3

改成this.setFont(new Font(str,Font.PLAIN,20));就好了 不能用g.setFont(new Font(str,Font.PLAIN,20));因为那是设置显示面板的字体，那不是Graphics对象的事情