When i tap on my button, my function was called

[myBtn addTarget:self action:@selector(myFunction) forControlEvents:UIControlEventTouchUpInside];

In my function, a collection of complex statement will be executed and take a litte bit time to run, so i want to show Loading (UIActivityIndicatorView) as the following:

-(void) addTradeAction {
    //Show Loading
    [SharedAppDelegate showLoading];

    //disable user interaction
    self.view.userInteractionEnabled = NO;

    //execute call webservice in here - may be take 10s
    //Hide Loading
    [ShareAppDelegate hideLoading];
}

When tap on myBtn (my Button) -> after 3s or 4s, [ShareAppDelegate showLoading] was called.

It is unusual when i use [ShareAppDelegate showLoading] on other Function, -> it work very nice, i mean all the statement be executed in order.

All i want, when i tap on My Button, Loading will be called immediatelly.

Tks in advance