iOS Access dynamically created label from other method - ios

Question

I have created a TableView that contains UIViews, which hold a few other elements. These UIViews are created dynamically, as the data is called from a server. Inside each UIView there is a UILabel and a UIButtton. Once the button is clicked, I would like to have the corresponding label updated with some value. I was able to modify the UIButton and the view itself but unable to modify the UILabel. Here is an example of the method that is called when a UIButton is called. Right now it will change the background color of the corresponding UIView, but the label element does not work as intended. How can accomplish modifying this label element which is a subelement of the UIView?
- (void) heartPlus:(id)sender {
UIButton *button = (UIButton*) sender;
NSInteger id_num = button.tag;
UIView * view = (UIView *)[self.view.superview viewWithTag:id_num];
UILabel * label = (UILabel *)[view viewWithTag:id_num];
label.backgroundColor = [UIColor blueColor];
}
Creating the UIView along with adding the corresponding elements.
UIView * msgView = [[[UIView alloc] initWithFrame:CGRectMake(0,offSet,320,120)] init];
[msgView setTag:someID];
// Add button
UIButton * buttonUpdate = [UIButton buttonWithType:UIButtonTypeRoundedRect];
buttonUpdate.tag = someID;
[buttonUpdate addTarget:self action:#selector(heartPlus:) forControlEvents:UIControlEventTouchUpInside];
UILabel * labelHeart = [[[UILabel alloc] initWithFrame:CGRectMake(280,100,20,10)] init];
labelHeart.tag = someID;
// Add each element to the msgView
[msgView addSubview:buttonUpdate];
[msgView addSubview:labelHeart];

Answer 1

There is still some missing code, but as far as I can see you have the error in heartPlus method and viewWithTag does not return the correct view. Therefore the assignment of backgroundColor fails. The explanation is below:
You are first getting the parent view of view that contains UIButton and UILabel. I assume your view hierarchy looks something like this:
UITableViewCell
UIView (tag: someID)
UILabel (tag: someID)
UIButton (tag: someID)
So, if I assume there is no error in the line below and that it returns correct UITableViewCell (or whatever other view is the parent of both UILabel and UIButton):
UIView * view = (UIView *)[self.view.superview viewWithTag:id_num];
We can clearly see the problem with both UILabel and UIButton having the same tags. So if you ask the UITableViewCell for the view with tag, it will simply fail - returns nil.
There are multiple solutions to this problem, but the problem remains the same.
Do not give the UILabel the same tag as UIButton.
I assume you are a beginner with Objective-C so I would suggest you first look into some tutorials of how UIViews work. But to make it easier for you, here are few options:
Create a custom subclass of the UIView with UIView properties.
Use unique tags for UILabel and for UIButton. To find the correct id_num on click, use introspection and sender's superview, which is passed to you in a method.
You could easily loop through UIView's subviews property (which is an array) and find the UILabel manually - this works, if there is only one UILabel or you are looking for all of them.
But in either case, you need to rethink of how UITableView works. It is not a good practice to ask self.view.superview for viewWithTag and your method could already fail at this point.