how to store CGPoint in array - iphone

Question

Hi I am trying to store the move points in the NSMutableArray so I have tries like this
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *move = [[event allTouches] anyObject];
CGPoint MovePoint = [move locationInView:self.view];
if (MovePointsArray==NULL) {
MovePointsArray=[[NSMutableArray alloc]init];
}
[MovePointsArray arrayWithObjects:[NSValue valueWithCGPoint:MovePoint]];
}
but this doesn't work how can i store these points in NSMutableArray

Answer 1

You should use addObject: in the last line:
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *move = [[event allTouches] anyObject];
CGPoint MovePoint = [move locationInView:self.view];
if (MovePointsArray==NULL) {
MovePointsArray=[[NSMutableArray alloc]init];
}
[MovePointsArray addObject:[NSValue valueWithCGPoint:MovePoint]];
}

Answer 2

You should do like this :
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *move = [[event allTouches] anyObject];
CGPoint MovePoint = [move locationInView:self.view];
if (MovePointsArray == NULL) {
MovePointsArray = [[NSMutableArray arrayWithObjects:[NSValue valueWithCGPoint:MovePoint, nil];
}
else {
[MovePointsArray addObject:[NSValue valueWithCGPoint:MovePoint]];
}
}
don't forget to retain / relase the array as you don't see to use a property accessor.
Best, you should alloc/init the array in your init method and then only do here :
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *move = [[event allTouches] anyObject];
CGPoint MovePoint = [move locationInView:self.view];
[MovePointsArray addObject:[NSValue valueWithCGPoint:MovePoint]];
}

Answer 3

If you want to get an array using method arrayWithObjects you must also add nil as the last element of the array.
like so:
[MovePointsArray arrayWithObjects:[NSValue valueWithCGPoint:MovePoint], nil];
but to add an object to an existing array you should use addObject method
[MovePointsArray addObject:[NSValue valueWithCGPoint:MovePoint]];