Accessing Value of a property of a derived class

Question

I'm having trouble getting the value of a property of my class. My class is called ball and I'd like to get it's velocity (which i set but can change) from my view control.
Here is my ball.h code:
#import <Foundation/Foundation.h>
@interface Ball : UIImageView {
CGPoint ballVelocity;
int mXSpeed;
int mYSpeed;
float mAngle;
- (void)getVelocity:(CGPoint)speed;
- (void)move;
- (void)bounceHorizontal;
- (void)bounceVertical;
- (void)setSpeedX:(int)xSpeed Y:(int)ySpeed;
- (void)setVelocity:(CGPoint)speed;
- (CGPoint) ballVelocity;
@end
Here is my part of my ball.m code:
#import "Ball.h"
@implementation Ball
- (void)setVelocity:(CGPoint)speed {
ballVelocity = speed;
Here is my viewVontroller.h
#import <UIKit/UIKit.h>
@class Ball;
@interface BallsOfFireViewController : UIViewController {
IBOutlet UIImageView *ball;
NSMutableArray *mBallArray;
CGPoint ballVelocity;
CGPoint velocityz;
CGPoint velocityz2;
@property(nonatomic, retain) IBOutlet UIImageView *ball;
@property(retain, nonatomic) IBOutlet NSMutableArray *mBallArray;
@property(nonatomic) CGPoint ballVelocity;
- (void) checkCollision;
@end
and here is the relative code from my viewController.m
#import "BallsOfFireViewController.h"
#import "Ball.h"
//#define kGameStateRunning 1
//#define kGameStatePaused 2
#define kBallSpeedX 1
#define kBallSpeedY 1
@implementation BallsOfFireViewController
@synthesize ball, mBallArray, ballVelocity;
- (void)viewDidLoad {
[super viewDidLoad];
//self.gameState = kGameStatePaused;
mBallArray = [[NSMutableArray alloc] init];
int i;
for (i = 0; i < 3; i++)
Ball* ballx=[[Ball alloc] initWithImage:[UIImage imageNamed:@"FireBall.png"]];
[mBallArray addObject:ballx];
[self.view addSubview:ballx];
if (i == 14
//[ballx setBackgroundColor:([UIColor redColor])];
ballx.image = [UIImage imageNamed:@"IceBall.png"];
ballVelocity = CGPointMake(1,1);
[ballx setVelocity:ballVelocity];
ballx.center = CGPointMake((random() % 14) * 20 + 20 ,(random() % 20) * 20 + 20);
[NSTimer scheduledTimerWithTimeInterval:0.005
target:self
selector:@selector(moveBall)
userInfo:nil
repeats:YES];
-(void)moveBall
int i;
int numberOfBalls=[mBallArray count];
for (i = 0; i < numberOfBalls; i++)
Ball* ballz=[mBallArray objectAtIndex:i];
int i2;
for (i2 = 0; i2 < numberOfBalls; i2++)
if (i2 != i) {
Ball* ballz2=[mBallArray objectAtIndex:i2];
if (CGRectIntersectsRect(ballz.frame, ballz2.frame)) {
if (sqrt(pow(ballz.center.x - ballz2.center.x,2) + pow(ballz.center.y - ballz2.center.y,2)) <= pow(ballz.frame.size.width,2)) {
[ballz move];
velocityz = ballz.ballVelocity;
velocityz2 = ballz2.ballVelocity;
if (velocityz.x == velocityz2.x * -1 && velocityz.y == velocityz2.y * -1) {
if (pow(ballz.center.x - ballz2.center.x,2) > pow(ballz.center.y - ballz2.center.y,2)) {
[ballz bounceHorizontal];
[ballz2 bounceHorizontal];
} else {
[ballz bounceVertical];
[ballz2 bounceVertical];
[ballz move];
When I get to the following line in debug mode the game in my iPhone Simulator freezes and I do not see any errors in xCode (probably don't know where to look):
velocityz = ballz.ballVelocity;
I think I'm just not setting up my ball class correctly to be able to pull back the value of the ballVelocity variable. Can anyone point me in the correct direction?

Answer 1

Here's the error I see in the dubugger
[NSObject doesNotRecognizeSelector:]
this is the line of code it is trying to execute in viewController.m:
velocityz = ballz.ballVelocity
I do have this in my ball.h
- (CGPoint)ballVelocity;
the ballVelocity of the ball is set right after it is created. No idea why it thinks this is not recognized. I know it's probably something stupid but I just don't see it!