How To Change a Variable Name Depending on Another Variable? - iphone

Question

I have a UIImageView called platform1, platform2, platform3, etc. I have an int called platformNumber coming from one method (method1) into another method (method2).
Method2 (contents not useful to my question):
CGPoint origin = platform1.center;
CGPoint target = CGPointMake(platform1.center.x, platform1.center.y+10);
CABasicAnimation *bounce = [CABasicAnimation animationWithKeyPath:#"position.y"];
bounce.duration = 0.1;
bounce.fromValue = [NSNumber numberWithInt:origin.y];
bounce.toValue = [NSNumber numberWithInt:target.y];
bounce.repeatCount = 1;
bounce.autoreverses = YES;
[platform1.layer addAnimation:bounce forKey:#"position"];
How do I change it so whereever platform1.center.x appears, it changes to platform[platformNumber] depending in the platformNumber value passed through?
Thanks, any help would be much appreciated!

Answer 1

The answers proposing KVC are not scalable at all; please don't do that. You can't declare a variable at runtime, so would will be stuck with however many image views you could attach a property too.
You need to build an array of your image views and iterate them. I repeat, KVC is not intended for this.
NSMutableArray *imageviews = [[NSMutableArray alloc] init];
//...
[imageViews addObject:platform1];
[imageViews addObject:platform2];
[imageViews addObject:platform3];
//...
Then iterate the array:
foreach (UIImageView *imgView in _imageViews) {
CGPoint origin = imgView.center;
CGPoint target = CGPointMake(imgView.center.x, imgView.center.y+10);
CABasicAnimation *bounce = [CABasicAnimation animationWithKeyPath:#"position.y"];
bounce.duration = 0.1;
bounce.fromValue = [NSNumber numberWithInt:origin.y];
bounce.toValue = [NSNumber numberWithInt:target.y];
bounce.repeatCount = 1;
bounce.autoreverses = YES;
[imgView.layer addAnimation:bounce forKey:#"position"];
}
int index = 3;
_imageViews[index]
returns you platform2 in your example (array start at 0, so subtract one)

Answer 2

Alternatively you can also create a function
-(UIImageView*)getPlatformForNumber:(int)number {
switch(number)
{
case 1:
return platform1;
case 2:
return platform2;
...
}
// should not come here
return nil;
}
and call that function where necessary. Sometimes that solution comes in handy - but the array proposed in davbryn's solution is of course more scalable.