for example in my program i want to draw a colorful line and before using getgraphics().drawline(..) i want to set the color to something by using setcolor() method.
is it possible to use the methods getGraphics().setColor(Color...) in a class extending JFrame?i have a problem here. Whenever i used it the color didn't change.
You don't do custom painting in a JFrame. You extend JComponent or JPanel and override the paintComponent(...) method.
Read the Swing tutorial on "Custom Painting" for more information and examples:
http://java.sun.com/docs/books/tutorial/uiswing/painting/index.html
in my JFrame i have a Jpanel and i let the user only paint in this area.
or i can need another solution
i can write another class that is extending jpanel and overriding the void paint method but in my first class can i change the jpanel with the other one?i can remove the existing and add the new one but my frame includes many components so i automaticly set them by using netbeans. what can i do?or which one can i achieve?