iOS - Why is my UIImageView moving? - ios

Question

Here is my function for which I draw a metronome image within my iOS program.
When I load it, the metronome image is loaded, but "flies" down from the top left of the screen to the desired position. This is not the behavior I wanted - I simply want the image to appear at the desired position. Could someone enlighten me why this happens, and how to fix it?
Many thanks in advance.
Pier.
- (void) drawMetronomeForBeat: (int) beatNumber withNumberOfBeats:(int) noBeats
{
// remove any previous instances first
if (metronomeImageView)
{
[metronomeImageView removeFromSuperview];
}
NSString * imageName = #"metronome";
NSString * noBeatsStr = [NSString stringWithFormat:#"%d", noBeats];
NSString * beatNumberStr = [NSString stringWithFormat:#"%d", beatNumber];
imageName = [imageName stringByAppendingString:noBeatsStr];
imageName = [imageName stringByAppendingString:#"b"];
imageName = [imageName stringByAppendingString:beatNumberStr];
UIImage* image = [UIImage imageNamed: imageName];
UIImageView * symbolImageView = [[UIImageView alloc] initWithImage:image];
[symbolImageView setFrame:CGRectMake(410.0f, 215.0f, symbolImageView.frame.size.width, symbolImageView.frame.size.height)];
metronomeImageView = symbolImageView;
[self.view addSubview:symbolImageView];
}

Answer 1

Replace this line
[symbolImageView setFrame:CGRectMake(410.0f, 215.0f, symbolImageView.frame.size.width, symbolImageView.frame.size.height)];
with
[symbolImageView setFrame:CGRectMake(410.0f, 215.0f, 22, 22)]; //Change 22, 22 according to size that you need.
The image view will become larger or smaller according to the size of "real image" you are displaying. So it will move some where so that imageview will stay center aligned.
EDIT:
I think you are setting different frame for symbolImageView.
Try this
symbolImageView.frame = metronomeImageView.frame;

Answer 2

I was using the Controller to display the images. I restructured my code so that the images are always "drawn" in the drawRect of the view code, like this..
- (void)drawRect:(CGRect)rect
{
if (metronomeImage)
{
[metronomeImage drawInRect:CGRectMake(410.0f, 215.0f, metronomeImage.size.width, metronomeImage.size.height)];
}
}
This works with no problems - note that I just used drawInRect and just UIImage instead of setFrame and UIImageView. I suppose I'll just follow the convention that anything graphical should be done in the view code, and not the controller.