Draw grid of circles - ios

Question

What would be the best way on iOS to achieve drawing a grid of circles with fixed columns and rows ?. I would want to identify each circle when the user taps on it.
I tried using collection views but it seems CoreGraphics is meant for tasks like these.

Answer 1

You can create buttons dynamically as follows :
- (void)drawSheet
{
int numberOfRow=5;
int numberOfColumn=4;
float x = 1,
y = 20,
padding = 5,
width = (self.view.frame.size.width-(padding*(numberOfColumn-1)))/numberOfColumn,
height = (self.view.frame.size.height-(padding*(numberOfRow-1)))/numberOfRow;
int counter = 0;
for (int i=0; i<numberOfRow; i++) {
for (int j=0; j<numberOfColumn; j++) {
UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake(x, y, 74, 74)];
btn.layer.cornerRadius = btn.frame.size.width/2;
btn.layer.borderColor = [UIColor grayColor].CGColor;
btn.layer.borderWidth = 2.0;
[btn addTarget:self action:#selector(buttonPress:) forControlEvents:UIControlEventTouchUpInside];
btn.clipsToBounds = YES;
btn.tag = counter;
[self.view addSubview:btn];
x = x + width + padding;
counter = counter + 1;
}
x = 0;
y = y + height + padding;
}
}
When you tap on it, you will get tag of it :
- (IBAction)buttonPress:(UIButton *)sender{
NSLog(#"%ld",sender.tag);
}

Answer 2

hi Please check the below code. i have added 3 circles in a row, you could use more if you want.
- (void)viewDidLoad {
[super viewDidLoad];
UIView *circleView;
int x = 10;
int y = 20;
static int tagNum = 0;
for (int row=0; row < 5;) {
for (int cirNum =0 ; cirNum <3;) {
circleView = [[UIView alloc] initWithFrame:CGRectMake(x,y,100,100)];
circleView.alpha = 0.5;
circleView.layer.cornerRadius = 50;
circleView.backgroundColor = [UIColor blueColor];
circleView.tag = tagNum;
NSLog(#"tagNum is %d", tagNum);
[self.view addSubview:circleView];
cirNum ++;
x = x + 100;
tagNum ++;
//y = y + 20;
}
row++;
y = y + 100;
x = 10;
}
// Do any additional setup after loading the view, typically from a nib.
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
CGPoint location = [[touches anyObject] locationInView:self.view];
CGRect fingerRect = CGRectMake(location.x-5, location.y-5, 10, 10);
for(UIView *view in self.view.subviews){
CGRect subviewFrame = view.frame;
if(CGRectIntersectsRect(fingerRect, subviewFrame)){
//we found the finally touched view
//NSLog(#"Yeah !, i found it %#",view);
NSLog(#"view tag touched is %ld",view.tag);
}
}
}
output would look like this