如何将宽度，高度设置为Jframe？

Question

Hello im trying to make it so my getwidth and getheight can be automatically asigned from my Jframe

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import javax.swing.JComponent;
import java.awt.GradientPaint;
import java.awt.Polygon;
import java.awt.*;

/*
   component that draws the concert background
*/
public class Concertbackground
{  
    public void draw(Graphics g)
    {   
        // Recover Graphics2D 
        Graphics2D g2 = (Graphics2D) g;    
        //Background Top
        g2.setColor(Color.BLUE);
        Rectangle backgroundTop = new Rectangle (0, 0, getWidth(), getHeight() / 2); 
        g2.fill(backgroundTop);    
        // Background bottom
        g2.setColor(Color.GREEN);
        Rectangle backgroundBottom = new Rectangle (0, getHeight() / 2, getWidth(), getHeight() / 2); 
        g2.fill(backgroundBottom);
    }    
}

JFrame part

import javax.swing.JFrame;
import java.awt.BorderLayout;

public class Concert
{
   public static void main(String[] args)
   {
      JFrame frame = new JFrame();
      frame.setSize(1000, 800);
      frame.setTitle("Concert!");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    
      ConcertComponent component = new ConcertComponent();
      frame.add(component);    
      frame.setVisible(true);
   }       
}

Part that actually draws the classes I create

import java.awt.Graphics;
import javax.swing.JComponent;


public class ConcertComponent
{
    public void paintComponent(Graphics g)
    {
        ConcertSpeaker speaker1 = new ConcertSpeaker(400, 300);
        speaker1.draw(g);    
        ConcertSpeaker speaker2 = new ConcertSpeaker(0, 0);
        speaker2.draw(g);          
      Concertbackground background1 = new Concertbackground();
      background1.draw(g);           
    }    
}

If I am unclear basically i want to make my getheight and getwidth equal to the Jframe size regaurdless of what its set or changed to

Answer 1

frame.add(component);

is wrong. Please refer to Oracle's online doc about add and Component .

java.lang.Object

  java.awt.Component java.awt.Container javax.swing.JComponent 

As a conveniance add and its variants, remove and setLayout have been overridden to forward to the contentPane as necessary. This means you can write:

  frame.add(child); 

And the child will be added to the contentPane.