点击JButton显示图像

Question

正如标题所示，我试图创建一个有几个按钮的程序，每个按钮都会在点击时显示一张图片。 但是，我想知道如果不使用图形类如here并且没有将容器设为全局，这是否可能。 但是我试过这个，我的程序似乎没有将图像添加到我的面板。

下面是代码：

import javax.swing.*; 

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

public class PhotoAlbum extends JFrame implements ActionListener{ 

private JPanel imagePanel; 
private JPanel labelPanel; 
public PhotoAlbum(){ 
    super(); 
    Container contentPane = getContentPane(); 
    setSize(1800, 1000); 
    setDefaultCloseOperation(EXIT_ON_CLOSE); 

    setTitle("Button Demo"); //Theme here 
    contentPane.setBackground(Color.blue); 
    contentPane.setLayout(new BorderLayout()); 

    createButtons(contentPane); 
    instruction(contentPane); 
    createImageLabel(contentPane); 
} 

public void instruction(Container contentPane){ 
    JPanel instruction = new JPanel(); 
    instruction.setLayout(new FlowLayout()); 
    instruction.setBackground(Color.yellow); 
    Font fontType1 = new Font("Comic Sans MS", Font.BOLD, 40); 
    JLabel instruction1 = new JLabel("Click on the button to view a" 
      + " photo."); 
    instruction1.setForeground(Color.BLUE); 
    instruction1.setFont(fontType1); 
    instruction.add(instruction1); 
    contentPane.add(instruction, BorderLayout.SOUTH); 
} 

public void createButtons(Container contentPane){ 
    labelPanel = new JPanel(); 
    labelPanel.setBackground(Color.pink); 
    labelPanel.setLayout(new GridLayout(9,1)); 

    String[] imageLabel = new String[9]; 
    imageLabel[0] = "Image 1"; 
    imageLabel[1] = "Image 2"; 
    imageLabel[2] = "Image 3"; 
    imageLabel[3] = "Image 4"; 
    imageLabel[4] = "Image 5"; 
    imageLabel[5] = "Image 6"; 
    imageLabel[6] = "Image 7"; 
    imageLabel[7] = "Image 8"; 
    imageLabel[8] = "Exit"; 

    Color[] color = new Color[9]; 
    color[0] = Color.cyan; 
    color[1] = new Color(242, 121, 234); 
    color[2] = Color.red; 
    color[3] = Color.green; 
    color[4] = Color.blue; 
    color[5] = new Color(1, 255, 248); 
    color[6] = Color.magenta; 
    color[7] = new Color(205, 255, 1); 
    color[8] = new Color(205, 255, 1); 

    Font fontType = new Font("Times New Roman", Font.BOLD, 30); 


    JButton[] button = new JButton[9]; 
    for (int i=0; i<button.length; i++) 
    { 
     button[i] = new JButton(imageLabel[i]); 
     button[i].addActionListener(this); 
     button[i].setBackground(color[i]); 
     button[i].setFont(fontType); 
     labelPanel.add(button[i]); 
    } 

    contentPane.add(labelPanel, BorderLayout.WEST); 
} 

public void createImageLabel(Container contentPane){ 
    imagePanel = new JPanel(); 
    imagePanel.setBackground(Color.magenta); 
    contentPane.add(imagePanel, BorderLayout.CENTER); 
} 

public void actionPerformed(ActionEvent event){ 
    String actionCommand = event.getActionCommand(); 
    if(actionCommand.equals("Image 1")) { 
     JLabel addImage = new JLabel(); 
     ImageIcon image = new ImageIcon("picture1.jpg"); 
     addImage.setIcon(image); 
     imagePanel.add(addImage); 
     imagePanel.setBackground(Color.yellow); 
    } 

    else if(actionCommand.equals("Exit")) 
     System.exit(0); 
    else System.out.println("Error in button interface."); 

} 

public static void main(String[] args) 
{ 
    PhotoAlbum buttonGui= new PhotoAlbum(); 
    buttonGui.setVisible(true); 
} 


} 

Answer 1

安德鲁在他的评论暗示。像下面那样重构你的代码。

if(actionCommand.equals("Image 1")) { 
    JLabel addImage = new JLabel(); 
    URL url = getClass().getResource("picture1.jpg"); 
    if (url != null) { 
     ImageIcon image = new ImageIcon(url); 
     addImage.setIcon(image); 
     imagePanel.add(addImage); 
     imagePanel.setBackground(Color.yellow); 
     this.revalidate(); 
    } 
} 

和picture1.jpg是在我有PhotoAlbum.java相同的地方。

否则你的代码工作正常。尽管大图像显示不正确。