UILefreshControl在iOS7中闪烁

Question

If UIRefreshControl is started programmatically,(beginRefreshing and then endRefreshing ) when it is not visible, then there would be a continuous flicker in the UIRefreshControl animation on next manual refresh.

Add this method in UITableViewController subclass and do a pull to refresh after 2 seconds and you will see the flicker

-(void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];

    UIRefreshControl * refreshControl = [[UIRefreshControl alloc] init];

    self.refreshControl = refreshControl;

    [self.refreshControl beginRefreshing];

    double delayInSeconds = 2.0;
    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, 
    (int64_t)(delayInSeconds * NSEC_PER_SEC));
    dispatch_after(popTime, dispatch_get_main_queue(), ^(void){

        [self.refreshControl endRefreshing];
    });
}

How to avoid this flicker?

Answer 1

Put your code in the viewDidLoad or viewWillAppear instead of viewDidAppear.

Also, can you tell me the reasoning behind putting the code inside the viewDidAppear method, rather than viewDidLoad or viewWillAppear?