How to create Graph of points from array

[enk1du]

Hi,

I have to create a Graph from list with two columns of floats. So i have this:

List<Float> getFromFile = new ArrayList<Float>();
      Scanner sccan = new Scanner(new FileReader("D:\\Docs\\Java\\test.txt"));
      while (sccan.hasNext()) {
			
  		getFromFile.add(sccan.nextFloat());
      }
  	  sccan.close();
          Object maxValue = Collections.max(getFromFile );
	  Object minValue = Collections.min(getFromFile );

And i need a help with drawing points on a chart. I made simple frame with axes.

import java.awt.*;
import java.awt.event.*;

public class Paint extends Canvas {
	
	public Paint() {
		Frame frame = new Frame("Canvas");
		frame.addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent we) {
				System.exit(0);
			}
		});
		
		//Window
		setSize(900, 600);
		frame.add(this, "West");

		frame.pack();
		frame.setResizable(false);
		frame.setVisible(true);
		
		Panel panel1 = new Panel();
		panel1.setLayout(new GridLayout(3,1));
		panel1.add(new Checkbox("Wyb\u00f3r 1",true));
		frame.add(panel1, "Center");
	}

 public void paint(Graphics g) {
	 
	 super.paint(g);

	 //axes
	 g.drawLine(400, 0, 400, 600);
	 g.drawLine(0, 300, 793, 300);

	 //scale
	 for (int i = 0; i < 800; i+=40) {
		 g.drawLine(i, 305, i, 295);
	 }

	 for (int j = 20; j < 600; j+=40) {
		 g.drawLine(395, j, 405, j);
	 }
	 
	  //arrows
	  g.drawLine(395, 5, 400, 0);
	  g.drawLine(405, 5, 400, 0);
	  g.drawLine(789, 295, 793, 299);
	  g.drawLine(789, 305, 793, 299);
}
}

I have problem with getting a max and rest of the points from getFromFile.

[DarrylBurke]

Why are you using the AWT Canvas which was superseded by the Swing JPanel more than 10 years ago?

Recommended tutorials: Lesson: Performing Custom Painting (The Java™ Tutorials > Creating a GUI With JFC/Swing) and Lesson: Getting Started with Graphics (The Java™ Tutorials > 2D Graphics)

db

[enk1du]

Why are you using the AWT Canvas which was superseded by the Swing JPanel more than 10 years ago?

Recommended tutorials: Lesson: Performing Custom Painting (The Java™ Tutorials > Creating a GUI With JFC/Swing) and Lesson: Getting Started with Graphics (The Java™ Tutorials > 2D Graphics)

db

Yeah, I red that, but there is nothing about drawing points from the ArrayList...
I'm beginner and I think JPanel is useless for me if I don't know how to draw in AWT.

[Tolls]

It's a lot easier than AWT.

[enk1du]

OK, I will learn it but any help with implementation of Scanner in AWT?

[quad64bit]

Why are you using AWT again? It's deprecated. You should be doing it in Swing. AWT is over a decade old, there is no use in learning it at this point, it is more trouble than it is worth.

[Tolls]

Either way, you seem to have a Collection of Floats.
So pass that to your JPanel (OK, Canvas).

Then, when you (re)paint you can simply refer to the collection.