JTabbedPane图像对齐

Question

I made a quick research to solve this problem but until now I found nothing regarding to this. I have one image into one TabbedPane object but when I try to align this image on the center of the label inside the TabbedPane it "Doesn't" work. The center alignment in this case works only for horizontal view but I want to be in the center of both vertical and horizontal. Check out the sample below:

import java.awt.BorderLayout;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;

import com.sh.st.gui.MainScreen;

public class test {

    JTabbedPane tabbedPane = new JTabbedPane();
    JFrame mainFrame = new JFrame();

public static void main (String[] args){

        test t = new test();

    }

    public test(){

        JPanel entrance = new JPanel();
        JLabel lbImage1;
        JMenuBar bar;
        JMenu file, registerQuery;
        ImageIcon Logo= new ImageIcon("rsc/img/imagem.jpg");        


        lbImage1= new JLabel(Logo, JLabel.CENTER);
            entrance.add(lbImage1);
                tabbedPane.addTab("Entrance", null, entrance);
                    mainFrame.getContentPane().add( tabbedPane, BorderLayout.CENTER);
                        bar= new JMenuBar();
                            file= new JMenu("File");
                                registerQuery= new JMenu("Request");
                                    mainFrame.setVisible(true);
    }   

}

I guess its not so hard to do what I want but until now as I said, I found nothing, anyone could help please? thanks in advance

Answer 1

The JLabel alignment will only center horizontally due to the potitioning characteristics of its parent container. In this case it is the default layout for JPanel which is FlowLayout . This layout manager does not facilitate easy vertical alignment.

Provided that the JLabel lbImage1 will be the only component on the JPanel entrance , then GridLayout can be used to center the JLabel both horizontally and vertically:

entrance.setLayout(new GridLayout());