CODEWITHSUNDEEP
javaawt
ApplePie
ApplePie

Reputation: 8942

Java AWT drawString() does not display on window

I am following the examples from Java : The complete reference 8th edition (JDK 7) on AWT and I cannot succeed to display a string on the window that appears. The size and title are set correctly and the window shows up. If I output a string on the console in the paint() method I see that it actually gets called a few times but the string does not appear on the window of my application. I can't see where I diverged from the example; I actually have a bit less code (they added a mouse listener and a key listener) :\

import java.awt.Dimension;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class Main {
    public static void main(String[] args) {
        Application app = new Application();
        app.setSize(new Dimension(640, 480));
        app.setTitle("This is a test");
        app.setVisible(true);
    }
}

class MyWindowAdapter extends WindowAdapter {
    public void windowClosing(WindowEvent we) {
        System.exit(0);
    }
}

class Application extends Frame {
    public Application() {
        addWindowListener(new MyWindowAdapter());
    }

    public void paint(Graphics g) {
        System.out.println("Hey hey !");
        g.drawString("Test", 10, 10);
    }
}

Upvotes: 3

Views: 5649

Answers (2)

MadProgrammer
MadProgrammer

Reputation: 347314

The problem you're having is the fact that you are painting directly on top of the frame. The frame also includes the frame border, so position 0, 0 (or in your case 10, 10) is actually hidden UNDER the frame border.

You can see more about that here.

Instead, you should draw onto a Canvas and add that to the frame

enter image description here

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class BadFrame {

    public static void main(String[] args) {
        new BadFrame();
    }

    public BadFrame() {
        Application app = new Application();
        app.setSize(new Dimension(640, 480));
        app.setTitle("This is a test");
        app.setLayout(new BorderLayout());
        app.add(new MyCanvas());
        app.setVisible(true);
    }

    class MyWindowAdapter extends WindowAdapter {

        public void windowClosing(WindowEvent we) {
            System.exit(0);
        }
    }

    public class MyCanvas extends Component {

        @Override
        public void paint(Graphics g) {
            super.paint(g);
            System.out.println("Hey hey !");
            g.drawString("Test", 10, 10);
        }

    }

    class Application extends Frame {

        public Application() {
            addWindowListener(new MyWindowAdapter());
        }

    }
}

The next question that comes to mind is, why AWT? The API has being moth balled in favor of Swing. If nothing else, it's automatically double buffered ;)

ps- You may also find 2D Graphics of some interest, especially the discussion on text

Upvotes: 5

user908627
user908627

Reputation:

Your string gets drawn but is hidden under the title bar of the window. Just use e.g. 

g.drawString("Test", 10, 200);

and you'll see it appear

Upvotes: 1

Related Questions