java - How would I dynamically add swing component to gui on click?

Question

What I am looking to do is a similar principle to adding attachments to emails, you can click a button and a new browse box would open increasing the number of separate attachments you can have.

I'm fairly new so if someone could point me towards an example?

You can do it as you do it statically, but they may be nicer solutions depending on what you want to do. — khachik, Nov 25 '10 at 18:26

score 40 · Accepted Answer · edited Aug 13 '16 at 21:36

Sample code to add Buttons on the fly dynamically.

panel.add(new JButton("Button"));
validate();

Full code:

import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JPanel;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import java.awt.FlowLayout;
import java.awt.BorderLayout;

public class AddComponentOnJFrameAtRuntime extends JFrame implements ActionListener {

    JPanel panel;

    public AddComponentOnJFrameAtRuntime() {
        super("Add component on JFrame at runtime");
        setLayout(new BorderLayout());
        this.panel = new JPanel();
        this.panel.setLayout(new FlowLayout());
        add(panel, BorderLayout.CENTER);
        JButton button = new JButton("CLICK HERE");
        add(button, BorderLayout.SOUTH);
        button.addActionListener(this);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(500, 500);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent evt) {
        this.panel.add(new JButton("Button"));
        this.panel.revalidate();
        validate();
    }

    public static void main(String[] args) {
        AddComponentOnJFrameAtRuntime acojfar = new AddComponentOnJFrameAtRuntime();
    }
}

Resource

As far as I know, `revalidate()` and/or `validate()` should be followed by `repaint()` (or changes wont be refelcted) also using `validate()` is redundant as `revalidate()` calls `validate()` — David Kroukamp, Jan 04 '13 at 18:51
Calling `repaint()` after `validate()` or `revalidate()` is not always necessary. Though I do not know the conditions for when it is required... I have a case in my app where without `validate()`, `revalidate()`, and `repaint()` the window does not redraw when a component is added. Just adding `validate()` causes the new component to be displayed. — Jason, Aug 17 '17 at 15:16
@jmj - Thanks for the solution., actually its works when we dont have other task to perform inside `actionPerformed` method. But if i have some other task to perform, firstly its performing those task and at last moment `Button` is adding to the `panel`. I was expecting in the reverse case. First it should add `Button` in the `Panel` and perform other task for that `actionperformed` method. — Karthikeyan, Oct 19 '21 at 14:25

dacwe · Answer 2 · 2010-11-25T17:49:10.960

public static void main(String[] args) {

    final JFrame frame = new JFrame("Test");
    frame.setLayout(new GridLayout(0, 1));

    frame.add(new JButton(new AbstractAction("Click to add") {
        @Override
        public void actionPerformed(ActionEvent e) {

            SwingUtilities.invokeLater(new Runnable() {
                @Override
                public void run() {
                    frame.add(new JLabel("Bla"));
                    frame.validate();
                    frame.repaint();
                }
            });
        }
    }));

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 300);
    frame.setVisible(true);
}

screenshot

score 2 · Answer 3 · edited Jan 14 '15 at 08:09

2

Component was not visible until setSize() was called:

component.setSize(100,200);
jPanel.add(component);
jPanel.revalidate();
jPanel.repaint();

edited Jan 14 '15 at 08:09

Magnilex

11,584
9
62
84

answered Jan 14 '15 at 08:00

Vidura Adikari

549
4
7

score 1 · Answer 4 · answered Aug 27 '15 at 13:40

1

panel.add(button);

panel.revalidate();

panel.repaint();

answered Aug 27 '15 at 13:40

Raj Trivedi

557
7
18

score 1 · Answer 5 · answered Aug 19 '16 at 11:47

Java : Dynamically add swing components

for Example : count=3
//Java Swing: Add Component above method
public void  dya_addcomp(int count)
{
//Dynamicaly Delete Image_icon
 BufferedImage Drop_Tablefield = null;
 try {
     Drop_Tablefield = ImageIO.read(this.getClass().getResource("/images/drop.png"));
 } catch (IOException ex) {
     msg(" Error: drop and edit icon on Table, "+ex);
 }
 //count Items:  3 times for loop executed..
 for(int i=0;i<count;i++)
 {
     //cnt++;
     //lblcount.setText("Count : "+cnt);
     JTextField txtcolnm=new JTextField("",20);
     JComboBox cmbtype=new JComboBox();
     JTextField txtcolsize=new JTextField("",20);

     JButton Drop_Table_Field = new JButton(new ImageIcon(Drop_Tablefield));

     cmbtype.addItem("INTEGER"); cmbtype.addItem("FLOAT");
     cmbtype.addItem("STRING");  cmbtype.addItem("BOOLEAN");

     colnamepanel.add(txtcolnm);   colnamepanel.add(cmbtype);
     colnamepanel.add(txtcolsize); colnamepanel.add(Drop_Table_Field);

     colnamepanel.setAutoscrolls(true);

     //refresh panel
     colnamepanel.revalidate();
     colnamepanel.repaint();

     //set the layout on Jpanel
     colnamepanel.setLayout(new FlowLayout(FlowLayout.LEFT,5,0));
  }//end for loop
 }//end method

java - How would I dynamically add swing component to gui on click?

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