ch7_e7_7.java

来自「各种关于JAVA的初级编程」· Java 代码 · 共 43 行

import java.applet.*;
import java.awt.*; 
import java.awt.event.*;

public class ch7_e7_7 extends Applet implements ActionListener
{
    Label promptLbl = new Label("请输入欲显示的图像文件名：");
    TextField inputTfd = new TextField(20);
    Button getImageBtn = new Button("显示图像");
    Image myImage;
    
    public void init()
    {
        add(promptLbl);
        add(inputTfd);
        add(getImageBtn);
        
        inputTfd.setText(" ");
        getImageBtn.addActionListener(this);
    }
    
    public void paint(Graphics g)
    {
        if(myImage != null)
            g.drawImage(myImage,10,100,this);
    }
    
    public void actionPerformed(ActionEvent ae)
    {
        if(ae.getSource() == getImageBtn)
        {
            String str = inputTfd.getText().trim();
            
            //System.out.println(str.substring(Math.max(0,str.length()-4)) + ",");
            if(!(str.substring(Math.max(0,str.length()-4)).equals(".gif")))
                str = str.trim() + ".gif";
            //System.out.println(str + ",");
            myImage = getImage(getDocumentBase(),str);
            repaint();
        }
    }
}