Question

I have the following code which does a bit of housekeeping on a database:

-(void)housekeepDataBase{

    NSLog(@"gets called");

    UIView *translucentView=[[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 480)];
    translucentView.backgroundColor=[UIColor blackColor];
    translucentView.alpha=0.65;

    UIActivityIndicatorView *spinner=[[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
    spinner.frame=CGRectMake(110, 221.5, 100, 37);
    [translucentView addSubview:spinner];

    [spinner startAnimating];

    [self.view.window addSubview:translucentView];


    dispatch_queue_t fetchQueue = dispatch_queue_create("fetch stuff", NULL);

    dispatch_async(fetchQueue, ^{

        [self deleteBlank];

        [self housekeepHnmr];

        [self housekeepCnmr];

        dispatch_async(dispatch_get_main_queue(), ^{

            [translucentView removeFromSuperview];

            [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"house"];
            [[NSUserDefaults standardUserDefaults] synchronize];

            NSLog(@"gets also called");


        });

    });

    dispatch_release(fetchQueue);

}

Because it takes a while on the device to perform (25 seconds), I add translucent view and a spinner, so that the user knows he/she has to wait a bit.

The thing is that if this method is called with a taget action from a button, it works allright. However if I directly call the method from viewDidLoad, the database gets updated but the view doesn’t show up.
On the other hand if i implement the creation of the spinner inside fetchQueue, it works vice versa. Allright from viewDidLoad but not from the button/target action.

I’m probably doing it all wrong using a block that I don’t really need. Actually I don’t want the user to be able to touch anything during the update of the DB. But I found this snipped and, since it worked on the test I kept it.

Any suggestions on how to do it in a more proper way?

Thanks!

Answer 1

Instead of viewDidLoad, use viewDidAppear (but make sure that it only runs once). The view hasn’t been shown yet so you can’t add the spinner in viewDidLoad.