[JAVA] Timer e disegno linee

[kainard]

Il programma apre una finestra che genera linee con alcune proprietà randomizzate. Vorrei però far disegnare una linea ogni secondo, come devo usare il timer? non riesco a farlo

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

public class Ex3 extends JFrame{

	public int WIDTH = 400;
	public int HEIGHT = 400;
					
	public Ex3(){
		
		Container c = this.getContentPane();
		this.setBackground(Color.WHITE);
		
		Toolkit tk = Toolkit.getDefaultToolkit();
		int SCREEN_W = tk.getScreenSize().width;
		int SCREEN_H = tk.getScreenSize().height;
		this.setBounds((SCREEN_W - WIDTH)/2,(SCREEN_H - HEIGHT)/2,WIDTH,HEIGHT);
		this.setTitle("Esercizio 1");
		this.setVisible(true);
		Dimension size = getSize();
		
	}
	public void paint(Graphics g){
		Dimension size = getSize();
		int x,y,x1,y1;
		float[] stroke = {2.0f,3.0f,4.0f,5.0f};
		
		 for(int i = 0;i<=100;i++) {
			x = (int)(Math.random()*(size.width-30)); 
			y = (int)(Math.random()*(size.width-30));
			Graphics2D g2d = (Graphics2D)g;
			/* Per ottenere le linee con gradienti
			  Color g1 = new Color((int)(Math.random()*256),(int)(Math.random()*256),(int)(Math.random()*256));
			Color g2 = new Color((int)(Math.random()*256),(int)(Math.random()*256),(int)(Math.random()*256));
			g2d.setPaint(new GradientPaint(x,y,g1,(size.width-30)-x,(size.width-30)-y,g2,true));
			*/
			g.setColor(new Color((int)(Math.random()*256),(int)(Math.random()*256),(int)(Math.random()*256)));
			float s = stroke[(int)(Math.random()*3)];
			g2d.setStroke(new BasicStroke(s));
			g.drawLine(x,y,(size.width-30)-x,(size.width-30)-y);
			
			}
				
		}
	public static void main(String[] args) {
		Ex3 app = new Ex3();
		app.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}

}

[kainard]

ho provato a fare anche un prog semplice sui timer ma non funziona, mi spiegate come si usano e come correggere il seguente prog?

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

public class prova { 
public static void main(String[] args) { 
  
  timer = new Timer(1000,new ActionListener() { 
   public void actionPerformed(ActionEvent e){ 
    System.out.println("Prova"); 
   }}); 

} 
}

[Andrea1979]

Timer è pure troppo per quel che devi fare: ho aggiunto un paio di righe al tuo programma

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

public class Ex3 extends JFrame{

        public int WIDTH = 400;
        public int HEIGHT = 400;

        public Ex3(){

                Container c = this.getContentPane();
                this.setBackground(Color.WHITE);

                Toolkit tk = Toolkit.getDefaultToolkit();
                int SCREEN_W = tk.getScreenSize().width;
                int SCREEN_H = tk.getScreenSize().height;
                this.setBounds((SCREEN_W - WIDTH)/2,(SCREEN_H - HEIGHT)/2,WIDTH,HEIGHT);
                this.setTitle("Esercizio 1");
                this.setVisible(true);
                Dimension size = getSize();
                this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        }
        public void paint(Graphics g){
                Dimension size = getSize();
                int x,y,x1,y1;
                float[] stroke = {2.0f,3.0f,4.0f,5.0f};

                 for(int i = 0;i<=100;i++) {
                        x = (int)(Math.random()*(size.width-30)); 
                        y = (int)(Math.random()*(size.width-30));
                        Graphics2D g2d = (Graphics2D)g;
                        /* Per ottenere le linee con gradienti
                          Color g1 = new Color((int)(Math.random()*256),(int)(Math.random()*256),(int)(Math.random()*256));
                        Color g2 = new Color((int)(Math.random()*256),(int)(Math.random()*256),(int)(Math.random()*256));
                        g2d.setPaint(new GradientPaint(x,y,g1,(size.width-30)-x,(size.width-30)-y,g2,true));
                        */
                        g.setColor(new Color((int)(Math.random()*256),(int)(Math.random()*256),(int)(Math.random()*256)));
                        float s = stroke[(int)(Math.random()*3)];
                        g2d.setStroke(new BasicStroke(s));
                        g.drawLine(x,y,(size.width-30)-x,(size.width-30)-y);
                        try {
                          Thread.sleep(1000);
                        }
                        catch (Exception e) {}

                        }

                }
        public static void main(String[] args) {
                Ex3 app = new Ex3();
                app.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        }

}

[kainard]

puoi spiegarmi plz la prima modifica? non ho capito come mai chiudi il frame. Poi per quanto riguarda la seconda, c'è modo di usare i timer invece dei thread? anche pkè vorrei imparare a usarli