Better way to initialize UIImageView with non-zero origin - iphone

Question

Creating UIImageView with some offset is quite common task when you're building interface in code.
I can see two ways to initialize UIImageView with origin not equal to (0,0):
First way requires only image filename and origin, but contains a lot of code (we can reduce number of lines by one using frame.origin = CGPointMake(x,y); ):
UIImageView *imgView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"image_filename"]];
CGRect frame = imgView.frame;
frame.origin.x = 150;
frame.origin.y = 100;
undoBg.frame = frame;
Second way has much less code, looks cleaner but we need to hardcode image size:
UIImageView *shadowView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 150, 800, 600)];
shadowView.image = [UIImage imageNamed:#"image_filename"];
What is best practice for you and why?
Thanks.

Answer 1

Hardcoding the images sizes is a form of Unnamed numerical constants which is an indication of Code Smell
This sort of thing should be avoided as much as possible as it can generate code that is a lot harder to maintain and is prone to human introduced errors. For example what happens when your graphic artist changes the size of the image? Instead of changing just one thing (the image) you now have to change many things (the image, and every place in the code where the image size has been hard coded)
Remember that you code not for today, but for the people who will come after you and maintain your code.
If anything, if you were really concerned about the extra lines of code, then you would abstract loading the UIImageView into a category, so that it can be used everywhere (note that this code is not tested):
#interface UIImageView (MyExtension)
-(UIImageView*)myLoadImage:(NSString*)named at:(CGPoint)location;
#end
#implementation
-(UIImageView*)myLoadImage:(NSString*)named at:(CGPoint)location
{
UIImageView *imgView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:named]];
CGRect frame = imgView.frame;
frame.origin.x = location.x;
frame.origin.y = location.y;
return imgView;
}
#end
Then you could simply do:
UIImageView* imageView = [UIImageView myLoadImage:#"image_filename" at:CGPointMake(150,100)];

Answer 2

I use the second one with slight modification,
UIImageView *shadowView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 150, 800, 600)];
shadowView.image = [UIImage imageWithData:[NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:fileName ofType:extension] ];
because imageNamed: caches image and cause memory leak.

Answer 3

I usually want my code to be easily readable. On the other hand I want the job done as fast as possible. In this case, there is so little code, I would go with less code. This is because I can get understand it so fast anyways. If it would be a much bigger example, I would use the easily readable code.

Answer 4

Surely it depends on your requirements. If I need to create an imageView in a class where the offset may change then I might do something like:
int myX = 10;
int myY = 100;
int myWidth = 200;
int myHeight = 300;
UIImageView *shadowView = [[UIImageView alloc] initWithFrame:CGRectMake(myX, myY, myWidth, myHeight)];
shadowView.image = [UIImage imageNamed:#"image_filename"];
but if I don't need to vary the offset and I know for a fact that the value won't change and no-one else will be needing to read or re-use my code then there's maybe nothing wrong (imho) with just using numbers in place of the int vars.
btw, you might want to avoid imageNamed as it caches the image which can lead to leaks.