Remove test_string from FrameTest class. Set test_string directly using set method. See example:
import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Test {
public static void main(String[] args) {
FrameTest1 test_frame = new FrameTest1();
test_frame.setContentString("I WANT TO DRAW THIS STRING");
}
}
class FrameTest1 extends JFrame {
private static final long serialVersionUID = 1L;
Painting painting = new Painting();
public FrameTest1() {
JFrame gui = new JFrame();
gui.setTitle("Test Title");
gui.setSize(400, 400);
gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container pane = gui.getContentPane();
pane.setLayout(new GridLayout(1, 1));
pane.add(painting);
gui.setVisible(true);
}
public void setContentString(String value) {
painting.test_string = value;
}
}
class Painting extends JPanel {
private static final long serialVersionUID = 1L;
String test_string;
public Painting() {
setBackground(Color.WHITE);
this.test_string = "TEMP STRING FROM PANEL";
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.RED);
g.drawString(test_string, 20, 20);
}
}