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G4P > two questions about Gwindow

[8 Replies]
- 16-Aug-2013 02:24 AM
- Forum: Contributed Library Questions
Hi everyone :^)
I have two questions.
First question is :

I have NPE problem. I've tried to solve by myself. But...

When I start my processing, usually it runs very well, but very very occasionally NPE occurs, not every time. To find the cause of NPE, I've used println almost everywhere in my code (I'm not sure whether it's a good way though). Now I guess that it occurs when Gwindow is initializing, because println("after window"); didn't execute. Is it right? Then what should I do?

This createControlWindow() method is located in void setup.
1. void createControlWindow()
2. {
3. int cwHeight = ssh+cwh;
4. println("ccw in : "+ssw+", "+cwHeight);
5. window = new GWindow(this, "ControlWindow", 0, 100, ssw, cwHeight, false, JAVA2D);
6. println("after window");
7. window.setBackground(0);
8. window.addDrawHandler(this, "windowDraw");
9. window.addMouseHandler(this, "windowMouse");
10. println("ccw end");
11. }
ccw in : 1440, 426

java.lang.NullPointerException

at processing.core.PApplet.handleDraw(PApplet.java:2301)

at processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:243)

at processing.core.PApplet.run(PApplet.java:2141)

at java.lang.Thread.run(Thread.java:680)
Second question is :

As I've mentioned above I've used println almost everywhere in my code to find the cause of NPE. Then I've found out that windowDraw (DrawHandler of Gwindow is called 'windowDraw'.) executes more often than void draw. Can I make that windowDraw executes only when void draw executes? not more not less.

G4P > Gwindow with for loop

[2 Replies]
- 13-Aug-2013 03:56 AM
- Forum: Contributed Library Questions
Hello there,
I've started to use Gwindow of G4P and faced with an error.

################ EXCEPTION IN EVENT HANDLER ################

An error occured during execution of the eventhandler:

CLASS: interactive_20130813 METHOD: windowDraw

Caused by java.lang.NullPointerException

interactive_20130813.windowDraw(interactive_20130813.java:739)

sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

java.lang.reflect.Method.invoke(Method.java:597)

g4p_controls.GWinApplet.draw(Unknown Source)

processing.core.PApplet.handleDraw(PApplet.java:2270)

processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:243)

processing.core.PApplet.run(PApplet.java:2141)

java.lang.Thread.run(Thread.java:680)

##############################################################

My code is as follows :

void windowDraw(GWinApplet appc, GWinData data)

{

appc.strokeWeight(typoWidth*s4cw);

appc.noFill();

for (int i=0 ; i < letters.length() ; i++)

{

for (int j = 0; j < alph[i].lpn; j++)

{

appc.pushMatrix();

if (!alph[i].isBezier[j]) //line

{

appc.translate(alph[i].sp[j].x*s4cw, alph[i].sp[j].y*s4cw);

if ( alph[i].spinning[j] || alph[i].process2stop[j] ) appc.rotate(alph[i].ra[j]);

appc.line(0, 0, alph[i].tp[j].x*s4cw, alph[i].tp[j].y*s4cw);

}

else //bezier

{

appc.translate(alph[i].sp[j].x*s4cw, alph[i].sp[j].y*s4cw);

if ( alph[i].spinning[j] || alph[i].process2stop[j] ) appc.rotate(alph[i].ra[j]);

appc.bezier(0, 0, alph[i].tp1[j].x*s4cw, alph[i].tp1[j].y*s4cw, alph[i].tp2[j].x*s4cw, alph[i].tp2[j].y*s4cw, alph[i].tp[j].x*s4cw, alph[i].tp[j].y*s4cw);

}

appc.popMatrix();

}

}

}

What I've found out is when I remove for loop, the error doesn't occur. But I really need for loop to draw things. How can I do? Can I ignore this error????? Actually the program is running though.

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