Centrare l'immagine in una JFrame?

Question

Sto creando un JFrame sul mio programma. Ho un'icona che ho usato per il programma e che ho come prima cosa su JFrame, ma sto riscontrando problemi nel centrare l'immagine. Se faccio un qualche tipo di centraggio, esso rovina l'intero allineamento di tutto il resto.

Sto provando ad avere tutti i JLabel, a parte l'icona, da allineare a sinistra. Quindi avere l'icona allineata al centro.

Ho dovuto rimuovere alcune informazioni personali, qualunque cosa abbia rimosso, le ho inserite tra "[]".

import java.awt.Dimension; 
import java.awt.Font; 

import javax.swing.BorderFactory; 
import javax.swing.Box; 
import javax.swing.BoxLayout; 
import javax.swing.ImageIcon; 
import javax.swing.JFrame; 
import javax.swing.JLabel; 
import javax.swing.JPanel; 

public class About extends JFrame { 

    public About() { 
     super("About [PROGRAM]"); 
     setIconImage([PROGRAM].getInstance().setIcon()); 

     JPanel main = new JPanel(); 

     main.setLayout(new BoxLayout(main, BoxLayout.Y_AXIS)); 
     main.setBorder(BorderFactory.createEmptyBorder(10,10,10,10)); 

     JLabel icon = new JLabel("", new ImageIcon(getClass().getResource(Constants.ICON_FULL)), JLabel.CENTER);   
     JLabel name = new JLabel("[PROGRAM]"); 
     JLabel expandedName = new JLabel("[PROGRAM DESCRIPTION]"); 
     JLabel copyright = new JLabel("[COPYRIGHT JUNK]"); 
     JLabel credits = new JLabel("[CREDITS]"); 

     name.setFont(new Font(name.getFont().getFamily(), Font.BOLD, 18)); 

     copyright.setBorder(BorderFactory.createEmptyBorder(0,0,10,0)); 

     main.add(icon); 
     main.add(Box.createRigidArea(new Dimension(0, 10))); 
     main.add(name); 
     main.add(expandedName); 
     main.add(copyright); 
     main.add(credits); 

     add(main); 

     pack(); 
     setLocationRelativeTo(null); 
     setVisible(true); 
    } 

} 

Answer 1

Considerare l'utilizzo di alcuni layout per aiutarti. Quelli che vengono in mente includono BorderLayout con l'icona nella posizione BorderLayout.CENTER. Puoi impilare elementi su un lato usando un BoxLayout usando JPanel che viene aggiunto al BorderLayout principale usando JPanel.

esempio,

import java.awt.BorderLayout; 
import java.awt.Font; 
import java.awt.event.ActionEvent; 
import java.awt.image.BufferedImage; 
import java.io.IOException; 
import java.net.MalformedURLException; 
import java.net.URL; 

import javax.imageio.ImageIO; 
import javax.swing.*; 

@SuppressWarnings("serial") 
public class About extends JDialog { 
    public static final String IMAGE_PATH = "http://upload.wikimedia.org/wikipedia/" 
     + "commons/thumb/3/39/European_Common_Frog_Rana_temporaria.jpg/" 
     + "800px-European_Common_Frog_Rana_temporaria.jpg"; 

    public About(JFrame frame) { 
     super(frame, "About [PROGRAM]", true); 

     ImageIcon myIcon = null; 
     try { 
     URL imgUrl = new URL(IMAGE_PATH); 
     BufferedImage img = ImageIO.read(imgUrl); 
     myIcon = new ImageIcon(img); 
     } catch (MalformedURLException e) { 
     e.printStackTrace(); 
     System.exit(-1); 
     } catch (IOException e) { 
     e.printStackTrace(); 
     System.exit(-1); 
     } 

     JPanel main = new JPanel(new BorderLayout()); 

     main.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10)); 

     JLabel centerLabel = new JLabel(myIcon); 
     JLabel name = new JLabel("[PROGRAM]"); 
     JLabel expandedName = new JLabel("[PROGRAM DESCRIPTION]"); 
     JLabel copyright = new JLabel("[COPYRIGHT JUNK]"); 
     JLabel credits = new JLabel("[CREDITS]"); 

     name.setFont(new Font(name.getFont().getFamily(), Font.BOLD, 18)); 

     copyright.setBorder(BorderFactory.createEmptyBorder(0, 0, 10, 0)); 

     int eb = 20; 
     centerLabel.setBorder(BorderFactory.createEmptyBorder(eb, eb, eb, eb)); 

     JPanel leftPanel = new JPanel(); 
     leftPanel.setLayout(new BoxLayout(leftPanel, BoxLayout.PAGE_AXIS)); 
     leftPanel.add(name); 
     leftPanel.add(Box.createVerticalGlue()); 
     leftPanel.add(expandedName); 
     leftPanel.add(copyright); 
     leftPanel.add(credits); 
     leftPanel.add(Box.createVerticalGlue()); 

     main.add(centerLabel, BorderLayout.CENTER); 
     main.add(leftPanel, BorderLayout.LINE_START); 

     add(main); 

     pack(); 
    } 

    public static void main(String[] args) { 
     final JFrame frame = new JFrame("GUI"); 
     JPanel panel = new JPanel(); 
     panel.add(new JButton(new AbstractAction("About") { 

     @Override 
     public void actionPerformed(ActionEvent e) { 
      About about = new About(frame); 
      about.setLocationRelativeTo(frame); 
      about.setVisible(true); 
     } 
     })); 
     frame.add(panel); 
     frame.pack(); 
     frame.setLocationRelativeTo(null); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     frame.setVisible(true); 
    } 
}