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giuseppe105

Thu Oct 22, 2009 4:10 pm


java forums?

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Why cant i post a question on them?

Ill ask my question here and hope i get help or it moves.

I am using java and i'm using the paint method to paint graphics.
g.drawImage(image object,int x,int y,object)

but since i am making a 2d grid i need to load an array of images. in this image array there will be values of the images that will appear in order.

i have code that looks like this rite now
for (int i = 0; i < fileLength; i++)
{
       g.drawImage(texture[i],i,i,null);
} 

this code is compileing fine but returning at least a hundred exceptions after i run the application.

what am i doing wrong or how can i do this in a different way?


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DemonWasp

Thu Oct 22, 2009 6:15 pm


RE:java forums?

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You really need to include the exception it's throwing, preferably along with its error message.


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giuseppe105

Thu Oct 22, 2009 6:48 pm


Re: RE:java forums?

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You really need to include the exception it's throwing, preferably along with its error message.

the program compiles with no errors but when it runs it returns all this.

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at drawMap.paint(drawMap.java:43)
    at javax.swing.JComponent.paintChildren(JComponent.java:864)
    at javax.swing.JComponent.paint(JComponent.java:1036)
    at javax.swing.JComponent.paintChildren(JComponent.java:864)
    at javax.swing.JComponent.paint(JComponent.java:1036)
    at javax.swing.JLayeredPane.paint(JLayeredPane.java:564)
    at javax.swing.JComponent.paintChildren(JComponent.java:864)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5129)
    at javax.swing.BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:277)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1217)
    at javax.swing.JComponent.paint(JComponent.java:1013)
    at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:21)
    at sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:60)
    at sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:97)
    at java.awt.Container.paint(Container.java:1780)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:814)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:714)
    at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:694)
    at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:128)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at drawMap.paint(drawMap.java:43)
    at javax.swing.JComponent.paintChildren(JComponent.java:864)
    at javax.swing.JComponent.paint(JComponent.java:1036)
    at javax.swing.JComponent.paintChildren(JComponent.java:864)
    at javax.swing.JComponent.paint(JComponent.java:1036)
    at javax.swing.JLayeredPane.paint(JLayeredPane.java:564)
    at javax.swing.JComponent.paintChildren(JComponent.java:864)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5129)
    at javax.swing.BufferStrategyPaintManager.paint(BufferStrategyPaintManager.java:277)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1217)
    at javax.swing.JComponent.paint(JComponent.java:1013)
    at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:21)
    at sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:60)
    at sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:97)
    at java.awt.Container.paint(Container.java:1780)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:814)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:714)
    at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:694)
    at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:128)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

Process completed.


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TheGuardian001

Thu Oct 22, 2009 6:59 pm


Re: java forums?

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Yeah, those would be errors.

 Specifically it's a null pointer exception, meaning you probably called a variable that wasn't initialized. 
You'll want to look at the lines mentioned (drawMap.java line 43) and check what variables it call upon, then insure you've initialized them.

And for future reference, at the top of the main Java forum are three sub forums titled "Java Tutorials," "Java Submissions," and "Java Help." You'll want to look at those.


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giuseppe105

Thu Oct 22, 2009 8:36 pm


Re: java forums?

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this is my code

import java.awt.*;
import java.io.*;
import javax.imageio.*;
import java.awt.image.*;
import javax.swing.*;
import java.util.*;

public class drawMap extends JPanel
{
	BufferedImage grass;
	mapLoader ml;
	BufferedImage[] textures; 
	
	int mapLength;
	
	public drawMap()
	{
		mapLoader ml = new mapLoader();
		mapLength = ml.getLength();
		try 
    	{
    		ml.loadMap();
    		grass = ImageIO.read(new File("Grass.png"));
    	} catch (IOException e) 
    	{
    	}
    	
    	BufferedImage[] textures = new BufferedImage[mapLength];
    	
    	Map textureList = new HashMap();
		textureList.put("grass",grass);
		
    	for (int x = 0; x