在Java中添加背景图像

Question

如何在此代码上添加背景图像？我尝试了一切，但图像不会显示。

import javax.swing.*; 
import java.awt.*; 
import java.awt.event.*; 

public class sampleProg extends JFrame { 

private Image img; 

public void sampleProg(){ 


ImageIcon icon = new ImageIcon("bg.jpg"); 

     img=icon.getImage(); 
} 

public void paint (Graphics g){ 

    g.drawImage(img,0,0,getSize().width,getSize().height,this); 
    super.paint(g); 

} 



JButton button = new JButton ("Result"); 
JButton button2 = new JButton ("Clear"); 


JLabel label = new JLabel ("Full Name"); 
JLabel label2 = new JLabel ("Age"); 
JLabel label3 = new JLabel ("English"); 
JLabel label4 = new JLabel ("Mathematics"); 
JLabel label5 = new JLabel ("Science"); 
JLabel label6 = new JLabel ("Social Studies"); 
JLabel label7 = new JLabel ("Height in cm"); 
JLabel label8 = new JLabel ("Weight in lbs"); 
JLabel label9 = new JLabel ("Message"); 
JLabel label10 = new JLabel ("Average"); 
JLabel label11 = new JLabel ("Remarks"); 
JLabel label12 = new JLabel ("Laurize Albarracin"); 



JTextField text = new JTextField (""); 
JTextField text2 = new JTextField (""); 
JTextField text3 = new JTextField (""); 
JTextField text4 = new JTextField (""); 
JTextField text5 = new JTextField (""); 
JTextField text6 = new JTextField (""); 
JTextField text7 = new JTextField (""); 
JTextField text8 = new JTextField (""); 
JTextField text9 = new JTextField (""); 
JTextField text10 = new JTextField (""); 
JTextField text11 = new JTextField (""); 

int average; 

JPanel background = new JPanel(); 
JFrame frame = new JFrame(); 

public sampleProg (String str){ 
    super(str); 

    background.setLayout (null); 
    background.setBounds (30,50,90,20); 

    button.setBounds(350,170,90,20); 
    button2.setBounds(450,170,90,20); 


    label.setBounds(30,90,90,20); 
    label2.setBounds(30,130,90,20); 
    label3.setBounds(30,170,90,20); 
    label4.setBounds(30,210,90,20); 
    label5.setBounds(30,250,90,20); 
    label6.setBounds(30,290,90,20); 
    label7.setBounds(350,90,90,20); 
    label8.setBounds(350,130,90,20); 
    label9.setBounds(350,210,90,20); 
    label10.setBounds(350,250,90,20); 
    label11.setBounds(350,290,90,20); 
    label12.setBounds(300,35,150,20); 




    text.setBounds(130,90,190,20); 
    text2.setBounds(130,130,190,20); 
    text3.setBounds(130,170,190,20); 
    text4.setBounds(130,210,190,20); 
    text5.setBounds(130,250,190,20); 
    text6.setBounds(130,290,190,20); 
    text7.setBounds(450,90,250,20); 
    text8.setBounds(450,130,250,20); 
    text9.setBounds(450,210,250,20); 
    text10.setBounds(450,250,250,20); 
    text11.setBounds(450,290,250,20); 

    button.addActionListener (new ActionListener() { 
     public void actionPerformed (ActionEvent e){ 

      text9.setText("Hi! "+text.getText()+"you are"+text2.getText()+"years of age and now you stand"+text7.getText()+"in cm while you're weight is"+text8.getText()+"in lbs. These are your remark and average"); 
      int English = Integer.parseInt (text3.getText()); 
      int Mathematics = Integer.parseInt (text4.getText()); 
      int Science = Integer.parseInt (text5.getText()); 
      int SocialStudies = Integer.parseInt(text6.getText()); 

      average = (English+Mathematics+Science+SocialStudies)/4; 
      text10.setText(Integer.toString(average)); 

     } 
    } 
    ); 

    button2.addActionListener (new ActionListener(){ 
     public void actionPerformed(ActionEvent e){ 
      text.setText(""); 
      text2.setText(""); 
      text3.setText(""); 
      text4.setText(""); 
      text5.setText(""); 
      text6.setText(""); 
      text7.setText(""); 
      text8.setText(""); 
      text9.setText(""); 
      text10.setText(""); 
      text11.setText(""); 

     } 
    }); 

    background.add(button); 
    background.add(button2); 
    background.add(label); 
    background.add(label2); 
    background.add(label3); 
    background.add(label4); 
    background.add(label5); 
    background.add(label6); 
    background.add(label7); 
    background.add(label8); 
    background.add(label9); 
    background.add(label10); 
    background.add(label11); 
    background.add(label12); 

    background.add(text);  
    background.add(text2); 
    background.add(text3); 
    background.add(text4); 
    background.add(text5); 
    background.add(text6); 
    background.add(text7); 
    background.add(text8); 
    background.add(text9); 
    background.add(text10); 
    background.add(text11); 

    getContentPane().add(background); 
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

    pack(); 
    } 

    public sampleProg(){ 

    setLayout(new FlowLayout()); 
} 

    public static void main (String[]args){  

    sampleProg frame = new sampleProg("Swing Application"); 
    frame.setSize(730,350); 
    frame.show(); 

} 


} 

Answer 1

您的代码不落img领域。将代码从void sampleProg()方法移到您的构造函数中。您还应该将background面板的background设置为透明颜色，以供图像显示。此外，您应该在background面板上绘制图像而不是在框架上，否则它将始终被遮盖。您可以创建一个匿名面板，并将代码移入其中。

在Mondain提供的链接中找到了更干净的方法。

public class sampleProg extends JFrame { 
    JPanel background = new JPanel() { 
     public void paint (Graphics g){ 
      g.drawImage(img,0,0,getSize().width,getSize().height,this); 
      super.paint(g); 
     } 
    }; 

    public sampleProg(string str) { 
     //... 

     ImageIcon icon = new ImageIcon("bg.jpg"); 
     img=icon.getImage(); 

     //... 

     Color transparent = new Color(0, true); 
     background.setBackground(transparent); 
    } 
} 

Answer 2

这可能会对你正在寻找的答案：How to set background image in Java?

Answer 3

Background Panel根据您的要求提供了一些解决方案。