Spawn UIImageView So That It Does Not Intersect With Existing UIImageViews - ios

Question

Basically, I have an app where a user dodges bombs and collects coins. When a user collects a coin, another coin is spawned. I want each coin to not spawn on a bomb. (By the way these are all uiimageviews). In the code below, I have an array of my bombs called bombArray and the UIImageview called "one" is the coin UIImageView. I know the code below doesn't work, but what other method(s) could I use? Thanks, and here is the code:
UIImageView *one = [[UIImageView alloc]initWithImage:[UIImage imageNamed:#"goldCoin.png"]];
CGRect rectOne = CGRectMake(arc4random() % (900), arc4random() % (700), 40, 40);
[one setFrame:rectOne];
[self.view addSubview:one];
for (UIImageView* two in bombArray)
{
while (CGRectIntersectsRect(two.frame, one.frame))
{
one.center=CGPointMake(arc4random() % (900), arc4random() % (700));
}
}
*Note: I completely understand why the code above does not work, but I cannot find another solution to my problem.

Answer 1

First of all to make such a thing I'd use the new SpriteKit that gives you physics (and thus collision detection) out of the box.
But if you want to do this with standard UIViews what you can do for being absolutely sure that images don't collide between them is to divide the container in a grid and then loop through each cell of your grid and "flip a coin" to randomly put a coin or not in that cell. Then if you want to fill more space instead of dividing for rectangular cells you can divide for hexagonal cells, in this way you will cover more space.
So a fast and absolutely not too much checked version could be something like this:
int x = 0;
int y = 0;
int side = 40;
int it = 0;
do {
do {
CGRect imageFrame = CGRectMake(x, y, side, side);
UIImageView* imageView = [[UIImageView alloc] initWithFrame:imageFrame];
imageView.layer.borderColor = [UIColor blackColor].CGColor;
imageView.layer.borderWidth = 1.0;
imageView.layer.cornerRadius = side / 2;
imageView.layer.masksToBounds = YES;
[self.containerView addSubview:imageView];
BOOL flip = arc4random() & 0x1;
if (flip) {
[imageView setImage:[UIImage imageNamed:#"coin_image"]];
}
} while ((x+=side) < (self.containerView.frame.size.width - side / 2));
it++;
if (it % 2 != 0) {
x = side / 2;
} else {
x = 0;
}
} while ((y+=(side * 0.85)) < (self.containerView.frame.size.height - side) );
Mind that this is NOT efficient, it is executed in the main thread and doesn't take in account possible (actually probable) memory constraints.