not getting output of java program

Question

package com.gautam.notepad;

import javax.swing.*;    

import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Graphics;
public class main {

    public static void main(String[] args) {
        panel1 p =new panel1();  // This is the panel1 class object
        new App("NOTEPAD",p);    // i'm trying to pass panel1 object



    }
}


class App extends JFrame {

    public App(String title,panel1 panel)
    {
        this.setTitle(title);
        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
        this.setVisible(true);
        this.setLocationRelativeTo(null);
        this.setSize(800, 640);
        this.setLayout(new FlowLayout());
        this.add(panel);
        this.setResizable(false);
    }
}

class panel1 extends JPanel{

    public void paintComponent(Graphics g)
    {
        g.setColor(Color.green);
        g.fillRect(0, 0, this.getWidth(), this.getHeight());



    }
}

it works fine but in the paintcomponent method it is g.fillRect() method is not working it is not painting the whole screen only small rectangle is painted in the middle of the screen.what is the problem in this code

Well you're missing a call to super.paintComponent(g), but the code is "fine". Its painting a rectangle the size of the JPanel. If you want the rectangle to be bigger, then you may need to investigate why your JPanel is not as big as you want it to be. Try commenting out that setLayout() line so the JFrame will still have its default BorderLayout, see if that makes a difference. — Gimby
– Gimby, Commented Jun 23, 2016 at 8:19

Aleksandar Marinkovic · Accepted Answer · 2016-06-23 08:31:52Z

1

You have problem on line this.setLayout(new FlowLayout());, just remove it and it will work. By default it will use BorderLayout which is what you need.

edited Jun 23, 2016 at 8:31

answered Jun 23, 2016 at 8:24

Aleksandar Marinkovic

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1 Comment

Aleksandar Marinkovic Over a year ago

Great :) You can also remove it since BorderLayout is used by default

Zaartha · Accepted Answer · 2016-06-23 08:22:15Z

0

This will work

import javax.swing.*;    
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
public class NotePad {

public static void main(String[] args) {

    App app = new App("NOTEPAD");  
    app.getContentPane().setBackground(Color.green);


}
}


class App extends JFrame {

public App(String title)
{
    this.setTitle(title);
    this.setDefaultCloseOperation(EXIT_ON_CLOSE);
    this.setVisible(true);
    this.setLocationRelativeTo(null);
    this.setSize(800, 640);
    this.setLayout(new FlowLayout());
    //this.add(panel);
    this.setResizable(false);
}
}

answered Jun 23, 2016 at 8:22

Zaartha

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1 Comment

Gautam Sharma Over a year ago

I doesn't want to display it in this way i want to draw a panel and in the panel void paint component method i like to paint the whole screen by the green colour by using the g.fillrect method

Seda · Accepted Answer · 2016-06-23 08:25:38Z

0

The problem has to do with your selected Layout.Have a look at this https://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html#flow to see the different layouts and how to use them.

If you change this.setLayout(new FlowLayout()); to this.setLayout(new BorderLayout()); for instance, it should work

answered Jun 23, 2016 at 8:25

Seda

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1 Comment

Seda Over a year ago

Please mark your question as answered if one of the suggested answers worked for you

Gherbi Hicham · Accepted Answer · 2016-06-23 08:43:45Z

0

Ok Flowlayout() gets it's own size and it happens that that small size is what you're getting from the flowlayout(), if you want to be still able to use the Flowlayout() and control the dimensions of your green Rectangle than i suggest using the setPreferredSize() method on your panel which will eliminate this problem and will keep your FlowLayout too.

public static void main(String[] args) {
        panel1 p =new panel1();  // This is the panel1 class object
        Dimension size= new Dimension(800, 640);//here you can add the size you want 
        p.setPreferredSize(size);
        new App("NOTEPAD",p);    // i'm trying to pass panel1 object



    }

edited Jun 23, 2016 at 8:43

answered Jun 23, 2016 at 8:37

Gherbi Hicham

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