Cannot call method

[David Schmidt]

I want to call "setI" from class1. Can somone help me and show me what is wrong?

public class Class1 {
	public static void main(String[] args) {
		MyPanel testPanel = new MyPanel();
		testPanel.setI(); //<<Does not work
	}
}

import javax.swing.JPanel;


public class MyPanel extends JPanel {
	private int i = 0;

	public int getI() {
		return i;
	}

	public void setI(int i) {
		this.i = i;
	}
	
	
}

Java is treating MyPanel exactly like a JPanel, and won't let me create any new methods for it
However I need to be able to call custom (and non-static) methods from the class. Is this possible?
If not, any alternatives?

[Tom Reilly]

I assume that when you say "Does not work", you mean that there is a compiler error. MyPanel.setI(int i) expects an integer as an input parameter. Do you know how to do this when calling the method?

[Rob Camick]

testPanel.setI(); //<<Does not work   

    public void setI(int i)

You need to pass an int variable to the setI(...) method.

[David Schmidt]

Once I changed that, it worked... which is really confusing. I tried to replicate a problem from a larger program without posting the code.

The error I get is
The method setDrawValues(String, int, int, int, int) is undefined for the type JPanel

I think it is a very stupid mistake, but I can't find it. I'll post the necessary code here:

	
public class MainApp {
	private static JFrame window;
	private static JPanel graph;
	private static JPanel buttonPanel;
	
	public static void main(String[] args) {
                window = new JFrame();
		window.setSize(300,300); //Set window to take half the screen
		
		graph = new MyGraphPanel();
		buttonPanel = new JPanel();
		
	
		window.setLayout(new BorderLayout()); //Set layout to put buttonPanel beside the graph.
		window.add(buttonPanel, "West");
		window.add(graph, "Center"); //add "graph" panel to the window.
		
		buttonPanel.setLayout(new BoxLayout(buttonPanel, BoxLayout.PAGE_AXIS));
		drawButtons(buttonPanel);
		
		graph.setDrawValues("y=x",-10,-10,10,10);	
		
		window.setVisible(true);
		
	}
}






public class MyGraphPanel extends JPanel { //inherits all methods from JPanel
	
	private String graphType;
	private int minX;
	private int minY;
	private int maxX;
	private int maxY;

	public void setDrawValues(String graphType, int minX, int minY, int maxX, int maxY)
	{
		this.graphType = graphType;
		this.minX = minX;
		this.minY = minY;
		this.maxX = maxX;
		this.maxY = maxY;
	}


}

[David Schmidt]

Moreover, when I type in graph. [CTRL + SPACE], "setDrawValues" is not even visible in the intellisense menu.
This is really confusing

[Rob Spoor]

You've declared graph as a JPanel. This means you can only call methods that are available in JPanel.

These two problems are not directly related to GUI programming so I'm moving this thread to Beginning Java.

[David Schmidt]

thank you.

Anyway, after some trial and error I managed to solve this by like this:

 ((MyGraphPanel) graph).setDrawValues("y=x",-10,-10,10,10);	

[Tom Reilly]

Whereas you created a MyGraphPanel, the variable graph is defined as a JPanel, which is fine because MyGraphPanel ISA JPanel. JPanel, however, does not have a setDrawValues() with the parameters that you specify.