如何设置JButton的大小？

Question

i am trying to set size of JButton, but by default it take whole frame, it's height easily set but i can't set it's width & why its behaving like that i don't know.

my code :

    JButton btnNewButton = new JButton("");
    btnNewButton.setPreferredSize(new Dimension(32,0));
    ImageIcon icon = new    ImageIcon(this.getClass().getResource("/images/images_Left.png"));
    btnNewButton.setIcon(icon);
    boxTlacitek.add(btnNewButton);
    getContentPane().add(btnNewButton, BorderLayout.NORTH);

any suggestion please ?

Answer 1

Change the layout. Try adding the button to another JPanel then add the panel the frame. BorderLayout will stretch the button across the available width of the panel when the component is placed in the NORTH or SOUTH position

import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class TestBorderLayout {

    public static void main(String[] args) {
        new TestBorderLayout();
    }

    public TestBorderLayout() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JButton fat = new JButton("Fat");
                JButton skinny = new JButton("Skinny");

                JPanel buttonPane = new JPanel();
                buttonPane.add(skinny);

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(fat, BorderLayout.NORTH);
                frame.add(buttonPane, BorderLayout.SOUTH);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

}

Answer 2

  getContentPane().setLayout(null);
  //setBounds(x,y,width,height)
  btnNewButton.setBounds(10,10,250,100);
  getContentPane().add(btnNewButton);