Question

i have a JFrame that contain a JButton when JFrame shows up, user will resize JFrame, then click the JButton which will do:

System.out.print("actual size now = "+JFrame.getsize");

but the size will not result the actual size of JFrame on the screen.

The size still wrong when i use:

• JFrame.getSize

• JFrame.getPrefferedSize

• JFrame.getMinimumSize

• JFrame.getMaximumSize

• JFrame.getBounds

• JFrame.getHeight & getwidth

what should i do?

Thanks a lot for any kind of help

Answer 1

The size you are getting is the size of the JFrames contentPane and the size of the Insets added. Simply call JFrame#getInsets() and subtract them from the JFrames width and height which you can get via JFrame#getSize().

Here is an example:

import java.awt.Dimension;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Test {

    public Test() {
        initComponents();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Test();
            }
        });
    }

    private void initComponents() {
        final JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel() {
            @Override
            public Dimension getPreferredSize() {//the frame should now return a width and height of 300
                return new Dimension(300, 300);
            }
        };

        JButton button = new JButton("Get JFrame real width and height");
        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent ae) {

                Dimension frameSize = frame.getSize();
                Insets insets = frame.getInsets();

                System.out.println("Frame size via getSize(): " + frameSize);
                System.out.println("Insets: " + insets);

                double width = frameSize.getWidth();
                double height = frameSize.getHeight();

                //calculate real width/height
                double realWidth = width - (insets.left + insets.right);
                double realHeight = height - (insets.top + insets.bottom);

                System.out.println("Width: " + realWidth + " Height: " + realHeight);
            }
        });

        panel.add(button);
        frame.add(panel);

        frame.pack();
        frame.setVisible(true);

    }
}

output:

Frame size via getSize(): java.awt.Dimension[width=316,height=338]

Insets: java.awt.Insets[top=30,left=8,bottom=8,right=8]

Width: 300.0 Height: 300.0