Thread: Beginning Swing help - resize API

Hi,

I'm working on a project where I am creating an Swing only API with buttons to draw graphs. Below is my code, when I run it and resize the window, the API goes blank. Is there anything simple I can do to make this more user friendly?

Thanks!

public GUI()
{
super("Bar Graphs"); // Window title

// Get the container and add the buttons

Container c = getContentPane();

c.setLayout(new FlowLayout());

quizButton = new JButton("Quiz Averages"); // Create a button
quizButton.addActionListener( this ); // Register the event handler
c.add(quizButton); // Add the button to the Application

homeworkButton = new JButton("Homework Averages"); // Create a button
homeworkButton.addActionListener( this ); // Register the event handler
c.add(homeworkButton); // Add the button to the Application

.....4 more buttons added

public void paint( Graphics g )
{

super.paint(g);

g.setColor(Color.red);
g.setFont(new Font("Times", Font.BOLD, 22));

if (drawQuizGraph == true)//Quiz button clicked, draw the graph when repaint() called
{
//graph label
g.drawString("Quiz Averages", 10, 150);

//Y axis graph labels
g.drawString("0 Students", 10, 750);
g.drawString("10 Students", 10, 650);
g.drawString("20 Students", 10, 550);
g.drawString("30 Students", 10, 450);
g.drawString("40 Students", 10, 350);
g.drawString("50+ Students", 10, 250);

//X axis graph labels
g.drawString("100-95", 145, 780);
g.drawString("94-90", 245, 780);
g.drawString("89-85", 345, 780);
g.drawString("84-80", 445, 780);
g.drawString("79-75", 545, 780);
....more bars drawn

// Event Handler Code
public void actionPerformed( ActionEvent e )
{
if (e.getSource() == quizButton)
{
drawQuizGraph = true;
repaint();
}
g.drawString("74 or less", 645, 780);

//draw the bars
g.setColor(Color.blue);
int x1 = 165;
int y1 = 700;
g.fillRect(x1, y1, 50, 50);

g.setColor(Color.green);
x1 = 265;
y1 = 700;
g.fillRect(x1, y1-100, 50, 150);
...more bars

You need to edit your post above and place [code] [/code] tags around your posted code so that it retains its formatting and is easier to read.

That being said, I'm confused in that it appears that you are dealing directly with a Graphics object, g, in your actionPerformed method, and that suggests that your code design is bad. Please tell and show us more. Are you in fact working with a Graphics object? If so where are you getting it from? Also, you almost never want to draw in a paint(...) method but rather a JPanel's paintComponent method for several reasons.

Originally Posted by curmudgeon

You need to edit your post above and place [code] [/code] tags around your posted code so that it retains its formatting and is easier to read.

That being said, I'm confused in that it appears that you are dealing directly with a Graphics object, g, in your actionPerformed method, and that suggests that your code design is bad. Please tell and show us more. Are you in fact working with a Graphics object? If so where are you getting it from? Also, you almost never want to draw in a paint(...) method but rather a JPanel's paintComponent method for several reasons.

I'm sure it's loaded with poor design as I am new to java and swing has been tough for me to grasp. I basically have a data file with scores I am reading into to a custom object. Based on these scores I want to create an API which will display diff avgs in a bar graph based on the button clicked. I have everything down except the API which I am having trouble laying out into a clean format display.

This is my first post in this forum and I appreciate your advice.

I can post my code when I get back to my pc

OK, we'll wait for you to return to your PC.

Originally Posted by curmudgeon

OK, we'll wait for you to return to your PC.

The code for my GUI class is below. I havent implemented the size of the graph bars as they are currently hardcoded.

My questions/problems so far are:

When I draw a graph and resize the window, the GUI goes blank, I would like it to resize with the window if within my extremely beginner scope...
Any suggestions on how to clean up the display/creation of the GUI? I only want to use Swing and keep it simple/primitive.

THanks!

 
 
 
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
 
@SuppressWarnings("serial")
 
public class GUI extends JFrame
	implements ActionListener
{
		//API buttons
		private JButton quizButton;
		private JButton homeworkButton;
		private JButton midtermButton;
		private JButton finalprojectButton;
		private JButton coursescoreButton;
		private JButton coursegradeButton;
 
		//button flags
		private boolean drawQuizGraph = false;
		private boolean drawHomeworkGraph = false;
		private boolean drawMidtermGraph = false;
		private boolean drawFinalProjectGraph = false;
		private boolean drawCourseAveragesGraph = false;
		private boolean drawCourseGradesGraph = false;
 
		//grade and score counters
		private int aGrades = 0;
		private int aMinusGrades = 0;
		private int bPlusGrades = 0;
		private int bGrades = 0;
		private int bMinusGrades = 0;
		private int cGrades = 0;
		private int midtermScore = 0;
		private int finalProjectScore = 0;
 
		// Constructor
		public GUI(HashMap<String, Student> studentMap) 
		{
			super("Graphs");  // Window title
 
			// Get the container and add the buttons
 
				Container c = getContentPane();
 
				c.setLayout(new FlowLayout());
 
				quizButton = new JButton("Quiz Averages");	// Create a button
				quizButton.addActionListener( this );	// Register the event handler
				c.add(quizButton);			// Add the button to the Application
 
				homeworkButton = new JButton("Homework Averages");	// Create a button
				homeworkButton.addActionListener( this );	// Register the event handler
				c.add(homeworkButton);			// Add the button to the Application
 
				midtermButton = new JButton("Midterm Scores");	// Create a button
				midtermButton.addActionListener( this );	// Register the event handler
				c.add(midtermButton);			// Add the button to the Application
 
				finalprojectButton = new JButton("Final Project Scores");	// Create a button
				finalprojectButton.addActionListener( this );	// Register the event handler
				c.add(finalprojectButton);			// Add the button to the Application
 
				coursescoreButton = new JButton("Course Averages");	// Create a button
				coursescoreButton.addActionListener( this );	// Register the event handler
				c.add(coursescoreButton);			// Add the button to the Application
 
				coursegradeButton = new JButton("Course Grades");	// Create a button
				coursegradeButton.addActionListener( this );	// Register the event handler
				c.add(coursegradeButton);			// Add the button to the Application
 
 
				Collection<Student> students = studentMap.values();
				Iterator<Student> mapItr = students.iterator();//map iterator
				while (mapItr.hasNext())//iterate to end of map
				{
					Student currentStudent = mapItr.next();
					if (currentStudent.getCourseGrade() == "A")
						aGrades++;
					else if (currentStudent.getCourseGrade() == "B+")
						bPlusGrades++;
					else if (currentStudent.getCourseGrade() == "B")
						bGrades++;
					else if (currentStudent.getCourseGrade() == "B-")
						bMinusGrades++;
					else 
						cGrades++;
 
					System.out.println("Totals printing");
					System.out.println(aGrades);
					System.out.println(bGrades);
					System.out.println(cGrades);
 
 
				}
 
		}
 
		public void paintGraphYLabels( Graphics g )//draws Y axis graph labels
		{
 
			g.drawString("0 Students", 10, 750);
			g.drawString("10 Students", 10, 650);
			g.drawString("20 Students", 10, 550);
			g.drawString("30 Students", 10, 450);
			g.drawString("40 Students", 10, 350);
			g.drawString("50+ Students", 10, 250);
		}
		public void paintGraphXLabels( Graphics g )//draws X axis graph labels
		{
 
			g.drawString("100-95", 145, 780);
			g.drawString("94-90", 245, 780);
			g.drawString("89-85", 345, 780);
			g.drawString("84-80", 445, 780);
			g.drawString("79-75", 545, 780);
			g.drawString("74 or less", 645, 780);
		}
 
		public void paintGraphBars( Graphics g )//method draws actual graph bars
		{
			//draw the bars
			g.setColor(Color.blue);
			int x1 = 165; 
			int y1 = 700;
			g.fillRect(x1, y1, 50, 50);
 
			g.setColor(Color.green);
			x1 = 265; 
			y1 = 700;
			g.fillRect(x1, y1-100, 50, 150);
 
			g.setColor(Color.orange);
			x1 = 365; 
			y1 = 700;
			g.fillRect(x1, y1-100, 50, 150);
 
			g.setColor(Color.yellow);
			x1 = 465; 
			y1 = 700;
			g.fillRect(x1, y1-100, 50, 150);
 
			g.setColor(Color.red);
			x1 = 565; 
			y1 = 700;
			g.fillRect(x1, y1-100, 50, 150);
 
			g.setColor(Color.pink);
			x1 = 665; 
			y1 = 700;
			g.fillRect(x1, y1-150, 50, 200);
 
		}
		public void paint( Graphics g ) 
		{
 
			super.paint(g);		
 
			g.setColor(Color.black);
			g.setFont(new Font("Times", Font.BOLD, 20));
 
			if (drawQuizGraph == true)//Quiz button clicked, draw the graph
			{
 
				g.drawString(" Quiz Averages", 10, 150);//graph title
				paintGraphXLabels(g);
				paintGraphYLabels(g);
				paintGraphBars(g);
 
				//set flag to false
				drawQuizGraph = false;
 
 
			}
			else if (drawHomeworkGraph == true)//Course Grade button clicked, draw the graph
			{
 
				g.drawString(" Homework Averages", 10, 150);//graph title
				paintGraphXLabels(g);
				paintGraphYLabels(g);
				paintGraphBars(g);
 
				drawHomeworkGraph = false;
 
			}
			else if (drawMidtermGraph == true)//Course Grade button clicked, draw the graph
			{
				g.drawString(" Midterm Scores", 10, 150);//graph title
				paintGraphXLabels(g);
				paintGraphYLabels(g);
				paintGraphBars(g);
 
				drawMidtermGraph = false;
 
			}
			else if (drawFinalProjectGraph == true)//Course Grade button clicked, draw the graph
			{
				g.drawString(" Final Project Scores", 10, 150);//graph title
				paintGraphXLabels(g);
				paintGraphYLabels(g);
				paintGraphBars(g);
 
				drawFinalProjectGraph = false;	
			}
			else if (drawCourseAveragesGraph == true)//Course Grade button clicked, draw the graph
			{
				g.drawString(" Course Score Averages", 10, 150);//graph title
				paintGraphXLabels(g);
				paintGraphYLabels(g);
				paintGraphBars(g);
 
				drawCourseAveragesGraph = false;	
			}
			else if (drawCourseGradesGraph == true)//Course Grade button clicked, draw the graph
			{
				g.drawString(" Course Grade Averages", 10, 150);//graph title
				paintGraphYLabels(g);
 
				//X axis labels
				g.drawString("A", 185, 780);
				g.drawString("A-", 285, 780);
				g.drawString("B+", 385, 780);
				g.drawString("B", 485, 780);
				g.drawString("B-", 585, 780);
				g.drawString("C", 685, 780);
 
 
				g.setColor(Color.blue);
				int x1 = 175; 
				int y1 = 700;
				g.fillRect(x1, y1, 50, 50);
 
				g.setColor(Color.green);
				x1 = 275; 
				y1 = 700;
				g.fillRect(x1, y1-100, 50, 150);
 
 
				g.setColor(Color.orange);
				x1 = 375; 
				y1 = 700;
				g.fillRect(x1, y1-100, 50, 150);
 
				g.setColor(Color.yellow);
				x1 = 475; 
				y1 = 700;
				g.fillRect(x1, y1-100, 50, 150);
 
				g.setColor(Color.red);
				x1 = 575; 
				y1 = 700;
				g.fillRect(x1, y1-100, 50, 150);
 
				g.setColor(Color.pink);
				x1 = 675; 
				y1 = 700;
				g.fillRect(x1, y1-150, 50, 200);
 
				drawCourseGradesGraph = false;
			}
		}
 
 
		// Event Handler Code, for each button clicked, set flag to true and corresponding draw graph
		public void actionPerformed( ActionEvent e ) 
		{
			if (e.getSource() == quizButton) 
			{
				drawQuizGraph = true;
				repaint();
			}
			else if (e.getSource() == homeworkButton) 
			{
				drawHomeworkGraph = true;
				repaint();	
			}
			else if (e.getSource() == midtermButton) 
			{
				drawMidtermGraph = true;
				repaint();
			}
			else if (e.getSource() == finalprojectButton) 
			{
				drawFinalProjectGraph = true;
				repaint();
			}
			else if (e.getSource() == coursescoreButton) 
			{
				drawCourseAveragesGraph = true;
				repaint();
			}
			else if (e.getSource() == coursegradeButton) 
			{
				drawCourseGradesGraph = true;
				repaint();
			}
 
		}
 
	}

You're problem is that you've got program logic inside of your painting method, code that changes the state of your program which is something that you should never do. Realize that this logic gets called at unpredictable times, including multiple times when you re-size your application. Instead put that logic elsewhere and use your painting methods for painting only, not to change boolean variables.

Another big error is that you're drawing in the paint(...) method of a JFrame, something else that should almost never be done. Instead read the painting with swing and AWt tutorial and draw with a paintComponent method that is held inside of a JPanel or JComponent extending class.

--- Update ---

What you're doing is essentially this:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
 
@SuppressWarnings("serial")
public class GUI2 extends JFrame implements ActionListener {
   private static final int PREF_W = 400;
   private static final int PREF_H = 300;
   private JButton quizButton  = new JButton("Quiz Averages");
   private boolean drawQuizGraph = false;
   public GUI2() {
      super("Graphs");
 
      JPanel panel = new JPanel();
      quizButton.addActionListener(this);
      panel.add(quizButton);
      add(panel, BorderLayout.NORTH);
 
      setPreferredSize(new Dimension(PREF_W, PREF_H));
   }
 
   public void paint(Graphics g) {
 
      super.paint(g);
 
      g.setColor(Color.black);
      g.setFont(new Font("Times", Font.BOLD, 20));
 
      if (drawQuizGraph) // == true is redundant and unnecessary 
      {
 
         g.drawString(" Quiz Averages", 10, 150);
 
         drawQuizGraph = false;
 
      }
   }
 
   public void actionPerformed(ActionEvent e) {
      if (e.getSource() == quizButton) {
         drawQuizGraph = true;
         repaint();
      }
 
   }
 
   public static void main(String[] args) {
      GUI2 gui = new GUI2();
 
      gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      gui.pack();
      gui.setLocationRelativeTo(null);
      gui.setVisible(true);
   }
 
}

--- Update ---

Note that even if you comment out the offending line:

// drawQuizGraph = false;

the code now works but when you resize there is nasty flashing of the graphics. This is solved by using the automatic double buffering provided by Swing derived JComponent classes (such as JPanel) paintComponent method. Test this example:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
 
@SuppressWarnings("serial")
public class GUI3 extends JPanel {
   private static final int PREF_W = 400;
   private static final int PREF_H = 300;
   private JButton quizButton = new JButton(new QuizButtonAction("Quiz Averages"));
   private boolean drawQuizGraph = false;
 
   public GUI3() {
      JPanel panel = new JPanel();
 
      panel.add(quizButton);
      add(panel, BorderLayout.NORTH);
   }
 
   @Override
   protected void paintComponent(Graphics g) {
      super.paintComponent(g);
      g.setColor(Color.black);
      g.setFont(new Font("Times", Font.BOLD, 20));
      Graphics2D g2 = (Graphics2D) g;
      g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
 
      if (drawQuizGraph) {
         g.drawString(" Quiz Averages", 10, 150);
      }
 
   }
 
   @Override
   public Dimension getPreferredSize() {
      return new Dimension(PREF_W, PREF_H);
   }
 
   private class QuizButtonAction extends AbstractAction {
      public QuizButtonAction(String name) {
         super(name);
      }
 
      @Override
      public void actionPerformed(ActionEvent arg0) {
         drawQuizGraph = true;
         repaint();
      }
   }
 
   private static void createAndShowGui() {
      GUI3 mainPanel = new GUI3();
 
      JFrame frame = new JFrame("Graphs");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(mainPanel);
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }
 
   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}