How to create bufferstrategy in a class which extends JPanel

Question

I am beginner in Java and I am having difficulties creating bufferstaregy in a class which extends JPanel but not canvas. Can some one show how to add buffer strategy here. I wrote very simplified code which illustrates my problem. I move rectangle in x and y position, however I can't see smooth movement of the rectangle at high speed. I hope that buffer strategy can solve this problem. I might be wrong. In any case what should I do here if I want to see smooth rectangle movement? I would be very grateful for any help. I am stucked at this position for a few days.

import javax.swing.*;
import java.awt.*;
public class simpleAnimation {
    public static void main(String args[]){
        Runnable animation = new moveAnimation();
        Thread thread = new Thread(animation);
        thread.start();
    }
}
// Creates window and performs run method
class moveAnimation implements Runnable{
    JFrame frame;
    int x = 0;
    int y = 0;
    boolean running = true;
    moveAnimation(){
        frame = new JFrame("Simple Animation");
        frame.setSize(600,600);
        frame.setResizable(false);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    public void run() {
        while(running == true){
            if(x<=500 || y<=500){
                x++;
                y++;
            }
            frame.add(new draw(x, y)); // I create new object here from different class which is below
            frame.setVisible(true);
            try {
                Thread.sleep(1);
            } catch (InterruptedException e) {
                e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
            }

        }

    }
}

// I use this class to draw rect on frame
class draw extends JPanel{
    int x;
    int y;
    draw(int x, int y){
        this.x=x;
        this.y=y;
    }
    public void paintComponent(Graphics g){
        Graphics2D g2 = (Graphics2D)g;
        g2.setColor(Color.BLACK);
        g2.fillRect(0,0,getWidth(),getHeight());
        g2.setColor(Color.GREEN);
        g2.fillRect(x,y,50,50);
    }
}

Swing components are double buffered by default, so why bother? As an aside, don't call GUI methods from a `Thread` other than the Event Dispatch Thread & don't `sleep` on the EDT. Use a Swing based `Timer` if need be. — Andrew Thompson, Jul 22 '13 at 20:11
also @AndrewThompson comments `running = true` should be `running == true` — nachokk, Jul 22 '13 at 20:17
I **strongly** recommend reading [Concurrency in Swing](http://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html) and [Performing custom painting](http://docs.oracle.com/javase/tutorial/uiswing/painting/index.html) lessons from the official [Swing tutorial](http://docs.oracle.com/javase/tutorial/uiswing/). They cover all the relevant topics from your code example. — linski, Jul 22 '13 at 20:35

score 0 · Answer 1 · answered Jan 22 '19 at 13:51

You can't really create a BufferStrategy on a class which extends JPanel using only that class the best option is too set "setDoubleBuffered" true this allows for a buffer of 2 but it doesn't exactly create an accessible bufferStrategy I would advise using a Canvas which you add to a JPanel that way you can get a bufferStrategy as well as smoother better controlled graphics

How to create bufferstrategy in a class which extends JPanel

1 Answers1