Help passing values to graphics

Question

I am able to create some graphics in a stand-alone app, but I am having some difficulty passing values from one class to a sub class of JPanel.
I can create a blank bar graph, the x and y axis, the title and labels, etc, but I need some values from another class passed in, and I'm not sure where to do this. Any suggestions would be appreciated.
Below is a simple gradebook program, and I want to be able to graph the individual scores along with the averages on each of three tests. The problem is in the DrawChart class.
thanks in advance!
//This starts the graphical representation of the data<br />
//----------------------------------------------------------------------------------------------------------//<br />
class DrawChart extends JPanel<br />
{ <br />
// constructor<br />
public DrawChart()<br />
{<br />
setBackground( Color.WHITE ); // set the background to white<br />
} // end DrawChart constructor<br />
<br />
// draws a Chart using concentric circles<br />
public void paintComponent( Graphics g, )<br />
{<br />
super.paintComponent( g );<br />
g.setColor(Color.BLACK);<br />
g.drawLine(30, 25, 30, 130); //this is the y-axis<br />
g.drawLine(25, 130, 605, 130); //this is the x-axis<br />
Font font = new Font("Serif", Font.PLAIN, 10);<br />
g.setFont(font);<br />
<br />
<br />
//each test score width = 10, space = 5, width for avg = 20, buffer between tests = 40<br />
//(10 bars and spaces = 150) + 20 = 170 for each test <br />
//170 * 3 + 40*2 = total width = 570, but allow the <br />
<br />
//The following are the values shown left of the y-axis. If there were many more, it would have been worth <br />
//while to set up a for/next loop to generate them<br />
//because of the way these are set, they are all left-justified <br />
g.drawString("100", 10, 30);<br />
g.drawString("90", 15, 40);<br />
g.drawString("80", 15, 50);<br />
g.drawString("70", 15, 60);<br />
g.drawString("60", 15, 70);<br />
g.drawString("50", 15, 80);<br />
g.drawString("40", 15, 90);<br />
g.drawString("30", 15, 100);<br />
g.drawString("20", 15, 110);<br />
g.drawString("10", 15, 120);<br />
//This will set up the labels below the x-axis<br />
g.drawString("Test 1", 65, 145);<br />
g.drawString("Avg.", 150,145);<br />
g.drawString("Test 2", 275, 145);<br />
g.drawString("Avg.", 360,145);<br />
g.drawString("Test 3", 485, 145);<br />
g.drawString("Avg.", 570,145);<br />
//set up light grey horz lines to make it easier to read the values<br />
g.setColor(Color.LIGHT_GRAY);<br />
g.drawLine(30, 30, 600, 30);//100%<br />
g.drawLine(30, 40, 600, 40);//90%<br />
g.drawLine(30, 50, 600, 50);//80%<br />
g.drawLine(30, 60, 600, 60);//70%<br />
g.drawLine(30, 70, 600, 70);//60%<br />
g.drawLine(30, 80, 600, 80);//50%<br />
g.drawLine(30, 90, 600, 90);//40%<br />
g.drawLine(30, 100, 600, 100);//30%<br />
g.drawLine(30, 110, 600, 110);//20%<br />
g.drawLine(30, 120, 600, 120);//10%<br />
int x; //this will be used to move the starting point <br />
x = 35; //initialize to 35 for the first bar<br />
g.setColor(Color.BLACK);<br />
for (int i = 0; i<3;i++)<br />
{<br />
for (int j = 0;j<10;j++)<br />
{<br />
if (testScores[i][j] == testMin) g.setColor(Color.RED); //red is bad - lowest score
else if(testScores[i][j] == testMax[i]) g.setColor(Color.GREEN);//green is good
g.fillRect(x,30 + 100 - testScores[i][j], 10, testScores[i][j]);//after drawing, set the color back to the default, black
g.setColor(Color.BLACK);
x = x + 15; //this will move the horz position for each of the 10 scores
} //this ends the inner loop, i
g.setColor(Color.CYAN);
g.fillRect(x,30 + 100 - testAvg[i], 20, testAvg[i]);//this will print the avg twice as wide
x = x + 40; //nice wide buffer to separate each group of tests the extra 40 at the end will not affect anything
} //ends outter loop, i }
} // end method paintComponent
// } // end class DrawChart
}//ends paintComponent method
} //End of main method
} //End of class

Answer 1

jeff_cia wrote:
Any thoughts on how to pass the values?Again, I can't read your code, and I doubt anyone else can. I can only give you the generic recommendation that if the data doesn't change you have setters in the class that needs to receive the data and getters in the class that's producing the data. If the data does change dynamically, then you'll probably want to use the Observable design pattern or something similar, something easy to do in Swing.