This what I am doing but is nothing is getting displayed on Jframe window. I have not extended class JFrame to do my, is it necessary to do so for displaying objects on window.
public class testGraphics {
static JFrame workingFrame = null;
public static void main(String args[])
{
JFrame workingManager = new JFrame("Hello");
workingManager.setSize(500, 500);
workingManager.setVisible(true);
Graphics g = workingManager.getGraphics();
JPanel jp = (JPanel) workingManager.getContentPane();
workingManager.paintComponents(g);
g.fillOval(0, 0, 30, 30);
g.drawOval(0, 50, 30, 30);
g.setColor(Color.CYAN);
}
}
Do not ever call getGraphics() or explicitly call paintXxx() to do custom painting. The correct way to do custom painting is to override the paintComponent method of the panel to paint on. The overriden method will be implicitly called for you. Then add that panel to the frame. Also you should override the getPreferredSize() of the panel, so it has a preferred size, so you can just pack the frame
class PaintPanel extends JPanel {
#Override
protected paintComponent(Grapchics g) {
super.paintComponent(g);
g.drawString(....);
}
#Override
public Dimension getPreferredSize() {'
return new Dimension(300, 300);
}
}
Then add it to the frame (or if you want to set it as the content pane of the frame, do that instead)
PaintPanel panel = new PaintPaint();
frame.add(panel);
...
frame.pack();
See more at Performing Custom Painting
I made several changes to your code to get it to work properly.
I changed your main method to call the SwingUtilities invokeLater method to make sure that the Swing components were defined and used on the Event Dispatch thread.
I created a drawing JPanel. I set the color first, then drew the ovals.
I added a JFrame default close operation. You must specify a default close operation, or else your Java application will continue running after you close the JFrame.
I moved the size to the drawing panel. The frame size will be calculated when you call the JFrame pack method.
And here's the modified code:
package com.ggl.testing;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestGraphics implements Runnable{
private JFrame workingManager;
private JPanel drawingPanel;
#Override
public void run() {
workingManager = new JFrame("Hello");
workingManager.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
drawingPanel = new DrawingPanel();
workingManager.add(drawingPanel, BorderLayout.CENTER);
workingManager.pack();
workingManager.setLocationByPlatform(true);
workingManager.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new TestGraphics());
}
public class DrawingPanel extends JPanel {
private static final long serialVersionUID =
-3701718376300985046L;
public DrawingPanel() {
this.setPreferredSize(new Dimension(500, 500));
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.CYAN);
g.fillOval(0, 0, 30, 30);
g.drawOval(0, 50, 30, 30);
}
}
}
The setSize() and setVisible() must be at the bottom of the method:
JFrame workingManager = new JFrame("Hello");
Graphics g = workingManager.getGraphics();
JPanel jp = (JPanel) workingManager.getContentPane();
workingManager.paintComponents(g);
g.fillOval(0, 0, 30, 30);
g.drawOval(0, 50, 30, 30);
g.setColor(Color.CYAN);
workingManager.setSize(500, 500);
workingManager.setVisible(true);
Related
So I am new in java graphics and I am creating a program that will show a rectangle. But when I run my program it only show like a small box and not the rectangle. I don't really know why it is happening.
Here is my code:
import javax.swing.*;
public class GraphicsEditor{
public static void main(String[] args) {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
Rectangle rectangle = new Rectangle();
frame.setSize(1280, 720);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.add(panel);
panel.add(rectangle);
}
}
This is my rectangle class:
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JPanel;
public class Rectangle extends JPanel implements Shape {
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2D = (Graphics2D) g;
g2D.fillRect(0, 0, 200, 130);
}
}
This is my shape interface:
import java.awt.*;
public interface Shape {
void paintComponent(Graphics g);
}
Here, try this
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.LineBorder;
public class GraphicsEditor {
public static void main(String[] args) {
JFrame frame = new JFrame();
Rectangle rectangle = new Rectangle();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(rectangle);
frame.pack();
// center frame on screen
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
class Rectangle extends JPanel {
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2D = (Graphics2D) g;
g2D.fillRect(0, 0, 200, 130);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(500, 500);
}
}
A couple of things.
you don't need the interface.
unlike components, just painting a picture doesn't affect the layout manager, so the panel will be reduced to it's default size with out regard to any painting.
so you need to override getPreferredSize() in your JPanel.
As the comments said, you should set the preferred size of both your panel and rectangle to your desired size, and then pack the frame, like:
panel.setPreferredSize(new Dimension(500,500));
rectangle.setPreferredSize(new Dimension(500,500));
frame.pack();
Otherwise your LayoutManager (when not specified it defaults to FlowLayout) will handle your rectangle the way it wants. So another way would be learning about Layout Managers, and using your desired one.
As a side note, I would like to make some suggestions to your code. Remember, Swing is not thread safe, so place your code inside an invokeLater() call, such as:
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
Rectangle rectangle = new Rectangle();
frame.setSize(1280, 720);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel.setPreferredSize(new Dimension(500,500));
rectangle.setPreferredSize(new Dimension(500,500));
frame.add(panel);
panel.add(rectangle);
frame.pack();
frame.setVisible(true);
}
});
Also, calling frame.setVisible(true) should be called after adding your components.
I'm building a PongClone but I encounter a bug. **I think the bug is cause by JPanel.
I tried the Image instead of BufferedImage.
I tried the drawImage outside the paintComponent method.
I create to another panel and then add that panel inside a mainpanel.
Menu Class
package me.pong;
import javax.swing.*;
public class TestMenu {
JFrame frame;
public void createFrame () {
TestMain main = new TestMain ();
frame = new JFrame("TEST");
frame.setSize (800, 450);
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane ().add (main.panel);
frame.setVisible (true);
}
}
MainClass
package me.pong;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
public class TestMain extends JPanel {
JPanel panel = new JPanel ();
BufferedImage img;
Graphics g;
public static void main (String[] args) {
TestMain testMain = new TestMain ();
TestMenu menu = new TestMenu ();
menu.createFrame ();
testMain.drawGraphics ();
}
public void drawGraphics(){
panel.add (new TestMain ());
img = new BufferedImage(800, 450, BufferedImage.TYPE_INT_RGB);
g = img.createGraphics ();
g.drawString ("TEST STRING 2", 250,250);
}
#Override
protected void paintComponent (Graphics g) {
super.paintComponent (g);
g.clearRect (0,0,800,450);
g.drawImage (img, 0,0,null);
g.setColor (Color.white);
g.drawString ("TEST STRING", 500,250);
g.setColor (Color.black);
g.drawRect (150,100,10,70);
}
}
I expect the Image fill the component but actual output is little tiny box.
Just like that
EDIT: Delete the code and added MCVE/SSCCE Code(I didn't know that). Still same. If I add the image inside the frame it's works but other way doesn't. I know I'm missing something, but I don't know what that is.
**Yes. Problem caused by JPanel but I don't know how to fix it.
The extra panel declared within the custom painted class that is a panel was not only unnecessary, but the source of problems. See further comments in code.
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
public class TestMain extends JPanel {
JFrame frame;
// Not needed or useful!
//JPanel panel = new JPanel();
BufferedImage img;
Graphics g;
public static void main(String[] args) {
TestMain testMain = new TestMain();
testMain.createFrame();
testMain.drawGraphics();
}
public void createFrame() {
TestMain main = new TestMain();
frame = new JFrame("TEST");
frame.setSize(400, 250);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//frame.getContentPane().add(main.panel);
frame.getContentPane().add(main);
frame.setVisible(true);
}
public void drawGraphics() {
//panel.add(new TestMain());
add(new TestMain());
img = new BufferedImage(800, 450, BufferedImage.TYPE_INT_RGB);
g = img.createGraphics();
g.drawString("TEST STRING 2", 250, 250);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.clearRect(0, 0, 800, 450);
// all JComponent instances are image observers
//g.drawImage(img, 0, 0, null);
g.drawImage(img, 0, 0, this);
g.setColor(Color.WHITE);
// NEW! Otherwise invisible
g.setColor(Color.RED);
g.drawString("TEST STRING", 200, 100);
g.setColor(Color.BLACK);
g.drawRect(150, 100, 10, 70);
}
}
As an aside:
That code still has problems, but I thought it best to stick closely to fixing only the immediate problem.
The easiest way to display a BufferedImage is to show it in a JLabel via an ImageIcon.
When I run this code. The result is a window with the name. Fully blank. I tried editing background color and adding graphics (rectangle) etc but the same result keeps occurring .
Question: This ends up as a white screen on a window. No graphics or background color. Even though I added it to panel and added panel. How do I fix this?
Main.java
package ball.tec.main;
import javax.swing.JFrame;
import ball.tec.frame.Frame;
public class Main {
public static void main(String[] args) {
String Version = "0.1.2";
Frame f = new Frame();
f.setVisible(true);
f.add();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setResizable(false);
f.setSize(1500, 1000);
f.setTitle("RedBall V: " + Version);
}
}
Frame.java
package ball.tec.frame;
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Frame extends JFrame{
private static final long serialVersionUID = 1L;
public boolean debug = false;
//Creating panel object
JPanel panel = new JPanel();
//Graphics displayed
public void paintComponent(Graphics g) {
//Firstly Nothing pops up
g.setColor(Color.RED);
g.drawRect(20, 40, 10, 10);
//And this doesn't work.
this.setBackground(Color.RED);
}
//Add everything to 'panel'
public void add() {
add(panel);
//Even if I put it here it doesn't work ;-;
this.setBackground(Color.RED);
this.pack();
}
}
You don't use paintComponent() in a JFrame. What you probably intended to do was create a third class, extending JPanel. Add your paintComponent() there.
public class MyPanel extends JPanel {
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.RED);
g.drawRect(20, 40, 10, 10);
this.setBackground(Color.RED);
}
}
f.add(new MyPanel());
I'm trying to display a message in a JPanel.
I've used the drawString() function of the Graphics class.
Here's my code :
public class Frame {
JFrame frame;
JPanel panel;
Graphics graph;
Frame() {
frame = new JFrame();
panel = new JPanel();
frame.setTitle("My wonderful window");
frame.setSize(800, 600);
frame.ContentPane(panel);
frame.setVisible(true);
}
void displayMessage(String message) {
graph = new Graphics();
graph.drawString(message, 10, 20);
}
}
I've this error :
error: Graphics is abstract; cannot be instantiated
Override the JPanel's paintComponent(Graphics g) method. IN the method you have access to a valid Graphics instance. The method called on each paint.
But may be it's better to add a JLabel to the panel. The label initially has no text and when you have a message just call setText(messageText) of the label.
You should create subclasses for your JFrame and JPanel, and override the methods you want. You could try something like:
package test;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Frame extends JFrame {
public static final String message = "HELLO WORLD!!!";
public class Panel extends JPanel {
public void paintComponent(Graphics graph) {
graph.drawString(message, 10, 20);
}
}
public Frame() {
Panel panel = new Panel();
this.setTitle("My wonderful window");
this.setSize(800, 600);
this.setContentPane(panel);
this.setVisible(true);
}
public static void main(String[] args) {
new Frame();
}
}
Also, there are a lot of great books/tutorials about this. You should read one.
Edit:
You should also read about all the JComponents (JButtons, JLabels...). They're rather useful.
I have this GUI class:
import java.awt.*;
import javax.swing.*;
public class Exp2 extends JFrame {
public Exp2 () {
setLayout(new FlowLayout());
setSize(360, 360);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
JPanel panel1 = new JPanel();
JPanel panel2 = new JPanel();
add(panel2);
add(panel1);
panel1.paint(null);
JButton button1 = new JButton("Run");
panel2.add(button1, BorderLayout.PAGE_END);
}
public void paint(Graphics g) {
g.setColor(Color.green);
g.fillRect(50, 50, 20, 20);
}
}
along with this main class:
import javax.swing.JFrame;
class Exp1 extends JFrame {
public static void main(String[] args) {
Exp2 box = new Exp2();
}
}
But the JButton button1 only appears after I roll my mouse over where it should be. What am I doing wrong?
You never call
super.paint(g);
which paints the containers child components.
Don't do custom painting in a top level container such as JFrame. Rather move the paint functionality to a subclass of JComponent. There override paintComponent rather than paint and invoke super.paintComponent(g). This takes advantage of the improved performance of Swing double buffering mechanism.
See: Performing Custom Painting
Call a repaint on the JFrame after you've added everything. Additionally, you need to call super.paint(g) from your paint method.