Need to get frame co-ordinate of image while animation - iphone

Question

I am using an app, in that am image is animating from top to bottom of screen using the animation.
code:
- (void)onTimer
{
// build a view from our flake image
flakeView = [[UIImageView alloc] initWithImage:flakeImage];
flakeView.backgroundColor=[UIColor blueColor];
// use the random() function to randomize up our flake attributes
int startX =round(random() % 460);
printf("\n ===== startX :%d",startX);
int endX = round(random() % 460);
printf("\n ===== endX :%d",endX);
double scale = 1 / round(random() % 100) - 1.0;
double speed = 1 / round(random() %100) + 1.0;
// set the flake start position
flakeView.frame = CGRectMake(startX, -100.0, 25.0 * scale, 25.0 * scale);
flakeView.alpha = 1.0;
// put the flake in our main view
[mView addSubview:flakeView];
[UIView beginAnimations:nil context:flakeView];
[UIView setAnimationDuration:20 * speed];
// code to get current position of image on view
CALayer mainLayer = flakeView.layer.presentationLayer;
CGRect layerFrame = mainLayer.frame;
BOOL intersects = CGRectIntersectsRect(layerFrame, dragger.frame);
// end position on screen
flakeView.frame = CGRectMake(endX, 500.0, 15.0 * scale, 15.0 * scale);
// set a stop callback so we can cleanup the flake when it reaches the
// end of its animation
[UIView setAnimationDidStopSelector:#selector(onAnimationComplete:finished:context:)];
[UIView setAnimationDelegate:self];
[UIView commitAnimations];
}
- (id)init
{
if(self = [super init])
{
mView = [[UIView alloc]initWithFrame:CGRectMake(0,0,320,440)];
mView.backgroundColor = [UIColor whiteColor];
mainLayer =[CALayer layer];
// load our flake image we will use the same image over and over
flakeImage = [UIImage imageNamed:#"apple.png"];
[mView.layer addSublayer:mainLayer];
// start a timet that will fire 20 times per second
[NSTimer scheduledTimerWithTimeInterval:(0.8) target:self selector:#selector(onTimer) userInfo:nil repeats:YES];
self.view=mView;
}
return self;
}
I used this to get position of an image that is animating from top to bottom of the screen.
but I am getting the connstant values of x and y for the image that is animating.
Can any one help in this.
Thank U.

Answer 1

One thing I have noted from above code is that you are adding flakeView each time on mView. Do you want so? Please try with following code.
- (void)onTimer
{
int startX =round(random() % 460);
printf("\n ===== startX :%d",startX);
int endX = round(random() % 460);
printf("\n ===== endX :%d",endX);
double scale = 1 / round(random() % 100) - 1.0;
double speed = 1 / round(random() %100) + 1.0;
if(flakeView == nil)
{
// build a view from our flake image
flakeView = [[UIImageView alloc] initWithImage:flakeImage];
flakeView.backgroundColor=[UIColor blueColor];
// use the random() function to randomize up our flake attributes
// set the flake start position
flakeView.frame = CGRectMake(startX, -100.0, 25.0 * scale, 25.0 * scale);
flakeView.alpha = 1.0;
// put the flake in our main view
[mView addSubview:flakeView];
}
[UIView beginAnimations:nil context:flakeView];
[UIView setAnimationDuration:20 * speed];
// code to get current position of image on view
CALayer mainLayer = flakeView.layer.presentationLayer;
CGRect layerFrame = mainLayer.frame;
BOOL intersects = CGRectIntersectsRect(layerFrame, dragger.frame);
// end position on screen
flakeView.frame = CGRectMake(endX, 500.0, 15.0 * scale, 15.0 * scale);
// set a stop callback so we can cleanup the flake when it reaches the
// end of its animation
[UIView setAnimationDidStopSelector:#selector(onAnimationComplete:finished:context:)];
[UIView setAnimationDelegate:self];
[UIView commitAnimations];
NSLog(#"Co-ordinates of imageview : (%f, %f, %f, %f) %#",flakeView.frame.origin.x,flakeView.frame.origin.y,flakeView.frame.size.width,flakeView.frame.size.height);
}
Thanks,

Answer 2

I'm wondering why you could use the dot-notation to access the presentationLayer. It is a method, not a property of CALayer.
Note: "Use of [UIView beginAnimations:context:] is discouraged in iPhone OS 4.0 and later. You should use the block-based animation methods instead." (Apple Docs). If you don't know what block-based animations are, read: What are block-based animation methods in iPhone OS 4.0?
If it still doesn't work with block-based animations, try to set the layer's delegate to nil or use CABasicAnimation either implicitly or explicitly.