How to put buttons and canvas into jframe? (Java swing)

Question

I have a JFrame and a few buttons and text fields inside. I'm using absolute positioning (null layout). I tried creating a canvas to draw on, but when I try to add the canvas to a container and then into the frame, the canvas overwrites all buttons. I want to have the canvas next to the buttons, both visible.

This is my code:

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Gui extends JFrame {
    private JLabel labEnterWord;
    private JTextField tfWord;
    private JButton butOk;

    public Gui(String title) {
        super(title);
        JPanel p = new JPanel();
        p.setLayout(null);

        //Create components and add them to the container
        addComponents(p);

        //Add containers to window
        getContentPane().add(p);
        getContentPane().add(new MyCanvas());

        setWindowProperties();
    }

    private void addComponents(JPanel p) {
        labEnterWord = new JLabel("Enter your word:");
        labEnterWord.setBounds(100, 60, 200, 30);                   
        labEnterWord.setFont(new Font("Arial", Font.PLAIN, 20));
        p.add(labEnterWord);

        tfWord = new JTextField();
        tfWord.setBounds(100, 100, 100, 25);
        tfWord.setFont(new Font("Arial", Font.PLAIN, 14));
        p.add(tfWord);

        butOk = new JButton("OK");
        butOk.setBounds(220, 100, 51, 25);
        butOk.addActionListener(new Event());
        p.add(butOk);
    }

    private void setWindowProperties(){
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
        setSize(1280, 720);
        setResizable(false);
        setLocationRelativeTo(null);
    }
}

MyCanvas class:

import javax.swing.*;
import java.awt.*;

public class MyCanvas extends JPanel {

    public void drawing(){
        repaint();
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);

        g.drawRect(500, 200, 200, 200);
    }
}

Main class just calls Gui().

Hint: although it seems tempting to use absolute positioning: don't ! Rather allow for the initial pain of learning about layout managers. But believe me: fixed-size frames are last millennium ;-) — GhostCat, Aug 29 '17 at 12:22
Use [borders](https://docs.oracle.com/javase/tutorial/uiswing/components/border.html) Luke! — Sergiy Medvynskyy, Aug 29 '17 at 12:23
Java GUIs have to work on different OS', screen size, screen resolution etc. using different PLAFs in different locales. As such, they are not conducive to pixel perfect layout. Instead use layout managers, or [combinations of them](http://stackoverflow.com/a/5630271/418556) along with layout padding and borders for [white space](http://stackoverflow.com/a/17874718/418556). — Andrew Thompson, Aug 29 '17 at 14:17

score 1 · Accepted Answer · answered Aug 29 '17 at 12:24

1

Here:

getContentPane().add(p);
getContentPane().add(new MyCanvas());

The first one adds your panel with your buttons to the frame. Then you add another thing to the frame!

Following your approach of placing everything manually, you rather add that canvas to your panel!

You disabled all means that would allow the JFrame resp. a layout manager to meaningfully place your panel and the canvas. Instead you push two elements into the frame, without telling the frame where that canvas should go to!

So you either need absolute placement for the canvas as well - or you step back and turn to a layout manager to do that for you.

answered Aug 29 '17 at 12:24

GhostCat

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I tried adding p.add(new MyCanvas()); to addComponents() method and deleted getContentPane().add(new MyCanvas()); but it doesn't seem to work either. The canvas just doesn't appear at all. – Peacetoletov Aug 29 '17 at 12:30
You also need to use `setBounds` with your canvas object. – ArcticLord Aug 29 '17 at 12:33
@Peacetoletov Again: what do you expect to happen when you add multiple components to a frame for which you disabled reasonable placing of elements? – GhostCat Aug 29 '17 at 12:34

How to put buttons and canvas into jframe? (Java swing)

1 Answers1