如何从NSObject类添加UIActivityIndi​​cator并对其进行控制？

Question

Class A: UIViewController Class B: NBOject class.

Add a UIActivityIndicator in Class A from Class B. control it from Class B.

Answer 1

I will do like this.

In appdelegate,

.h

@property (strong, nonatomic) ClassA *classA;
+ (AppDelegate *)instance;

.m

+ (AppDelegate *)instance
{
    return (AppDelegate *)[[UIApplication sharedApplication] delegate];
}

In Class A,

- (void)viewDidLoad
{
    [AppDelegate instance].classA = self; 
}

Then, in class B, which is NSObject class, you can just call class A via AppDelegate like this.

.h

UIActivityIndicatorView *activityIndicatorView;

.m

- (void)addActivityIndicator
{
    self.activityIndicatorView = [[UIActivityIndicatorView alloc] init];
    [[AppDelegate instance].classA addsubview:self.activityIndicatorView];
    [self.activityIndicatorView startAnimating];
}