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[java] Jbutton arrays?

Started by DefCom Nov 30, 2002 at 7:14 AM 2 replies 300+ views

Original Post

Nov 30, 2002 at 7:14 AM

I am using Jbuttons to create a floor plan so that the user can click on the appropriate room and the program will execute appropriatly. I am currently using individual JButtons which work just fine, but i wish to use an array for the JButtons, my code looks a little like this: JButton BFloorPlan[] = new JButton[12]; BFloorPlan[0].setIcon(Image01); BFloorPlan[0].setBounds(0,0,64,64); pane.add(BFloorPlan[0]); It compile with 0 errors but when i execute the function the program hangs as though i have written past the end of the array or the image is not available, both not true. Any help or advise would be much appriciated, thanks

neonoblivion

Nov 30, 2002 at 7:24 AM

I think you have to add after:
JButton BFloorPlan[] = new JButton[12];

some code which is like:
for(int index=0;index<12;index++)
BFloorPlan[index] = new JButton(/*whatever init params you want...*/);

that should do it. You aren't actualy instantiating a class of JButton with your code as-is.
Klaus

//edit:fixed the code

[edited by - neonoblivion on November 30, 2002 8:26:16 AM]

DefCom

Author

DefCom

Nov 30, 2002 at 7:34 AM

Thanks for the responce

I didn''t try it inside a loop, but i did try individual constructors, it just threw up errors.

Petr Stedry

Nov 30, 2002 at 9:30 AM

Hi DefCom,

just to be sure you do know what your code means ...

quote:
Original post by DefCom
JButton BFloorPlan[] = new JButton[12];

This line says: "There will be an array of JButton objects, that will be 12 elements long" or better "There will be an array that can accomodate up to 12 JButton (or simillar - read subclasses) objects".
So you told the computer that an array will exist, but didn't say a word about objects that it contains. Understand?

P.S.:
Try to avoid "magic numbers" - use constants instead! The program gets a lot more readable .
For example:
public static final int DEFAULT_FLOOR_PLAN_SIZE = 12;
...
JButton BFloorPlan[] = new JButton[DEFAULT_FLOOR_PLAN_SIZE];
is much more fun to read

just BTW

have fun ...

Petr Stedry

[edited by - Petr Stedry on November 30, 2002 10:31:20 AM]

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