Question

I have a view which is created in IB. inside it I have a scroll view created programmatically. Within the scroll view I connect to a web service and fetch the content and the image. I want to show an activity indicator while doing this. So I have:

- (void)viewDidLoad
{
    [super viewDidLoad];
    activityIndicator = [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
    activityIndicator.frame = CGRectMake(0.0, 0.0, 40.0, 40.0);
    activityIndicator.center = self.view.center;
    [self.view.window addSubview:activityIndicator];

And right after the scrollview is added, I have:

[self.view addSubview:scrollView];
// ADD Scroll View Ends


    //Add the Lisitng Image
    NSOperationQueue *queue = [NSOperationQueue new];
    NSInvocationOperation *operation = [[NSInvocationOperation alloc] 
                                        initWithTarget:self
                                        selector:@selector(loadImage) 
                                        object:nil];
    [queue addOperation:operation]; 

And in loadimage I have:

- (void)loadImage {

    [activityIndicator startAnimating];

I’ve tried [self.view.window addSubview:activityIndicator];, [self->ScrollView addSubview:activityIndicator];, [self.view addSubview:activityIndicator];

but I just can’t get the indicator to show. Anyone have any idea what might be wrong?

Answer 1

You should do this in you viewDidload

- (void)viewDidLoad
{
    //Start Activity Indicator View
    indicatorView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
    indicatorView.frame = CGRectMake(40.0, 20.0, 60.0, 60.0);
    indicatorView.center = self.view.center;
    [self.view addSubview:indicatorView];
    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
    [indicatorView startAnimating];

    [self performSelectorInBackground:@selector(loadscroll) withObject:self];
}

Note: “performSelectorInBackground” will show you an activity indicator on the view and your loadScroll method will fetch all data from internet and do other work.

-(void)loadscroll
{
    //Your Scroll View 
        //Your other Data Manipulation even from internet
        //When data is fetched display it 
       [self removeActivityIndicator]; //To stop activity Indicator       
}

- (void)removeActivityIndicator
{
       [indicatorView stopAnimating];
}