UIRefreshControl - beginRefreshing not working when UITableViewController is inside UINavigationController

Question

I've setup a UIRefreshControl in my UITableViewController (which is inside a UINavigationController) and it works as expected (i.e. pull down fires the correct event). However, if I programmatically invoke the beginRefreshing instance method on the refresh control like:

[self.refreshControl beginRefreshing];

Nothing happens. It should animate down and show the spinner. The endRefreshing method works properly when I call that after the refresh.

I whipped up a basic prototype project with this behavior and it works properly when my UITableViewController is added directly to application delegate's root view controller, e.g:

self.viewController = tableViewController;
self.window.rootViewController = self.viewController;

But if I add the tableViewController to a UINavigationController first, then add the navigation controller as the rootViewController, the beginRefreshing method no longer works. E.g.

UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:tableViewController];
self.viewController = navController;
self.window.rootViewController = self.viewController;

My feeling is this has something to do with the nested view hierarchies within the navigation controller not playing nice with the refresher control - any suggestions?

Thanks

Solution 1

It seems that if you start refreshing programmatically, you have to scroll the table view yourself, say, by changing contentoffset

[self.tableView setContentOffset:CGPointMake(0, -self.refreshControl.frame.size.height) animated:YES];

I would guess the reason for this is that it could be undesirable to scroll to the refresh control when user is in the middle/bottom of the table view?

Swift 2.2 version by @muhasturk

self.tableView.setContentOffset(CGPoint(x: 0, y: -refreshControl.frame.size.height), animated: true)

In a nutshell, to keep this portable add this extension

UIRefreshControl+ProgramaticallyBeginRefresh.swift

extension UIRefreshControl {
    func programaticallyBeginRefreshing(in tableView: UITableView) {
        beginRefreshing()
        let offsetPoint = CGPoint.init(x: 0, y: -frame.size.height)
        tableView.setContentOffset(offsetPoint, animated: true)        
    }
}

Solution 2

UITableViewController has automaticallyAdjustsScrollViewInsets property after iOS 7. The table view may already have contentOffset, usually (0, -64).

So the right way to show refreshControl after programmingly begin refreshing is adding refreshControl's height to existing contentOffset.

 [self.refreshControl beginRefreshing];
 [self.tableView setContentOffset:CGPointMake(0, self.tableView.contentOffset.y-self.refreshControl.frame.size.height) animated:YES];

Solution 3

Here's a Swift extension using the strategies described above.

extension UIRefreshControl {
    func beginRefreshingManually() {
        if let scrollView = superview as? UIScrollView {
            scrollView.setContentOffset(CGPoint(x: 0, y: scrollView.contentOffset.y - frame.height), animated: true)
        }
        beginRefreshing()
    }
}

Solution 4

None of the other answers worked for me. They would cause the spinner to show and spin, but the refresh action itself would never happen. This works:

id target = self;
SEL selector = @selector(example);
// Assuming at some point prior to triggering the refresh, you call the following line:
[self.refreshControl addTarget:target action:selector forControlEvents:UIControlEventValueChanged];

// This line makes the spinner start spinning
[self.refreshControl beginRefreshing];
// This line makes the spinner visible by pushing the table view/collection view down
[self.tableView setContentOffset:CGPointMake(0, -1.0f * self.refreshControl.frame.size.height) animated:YES];
// This line is what actually triggers the refresh action/selector
[self.refreshControl sendActionsForControlEvents:UIControlEventValueChanged];

Note, this example uses a table view, but it could just as well have been a collection view.

Solution 5

The already mentioned approach:

[self.refreshControl beginRefreshing];
 [self.tableView setContentOffset:CGPointMake(0, self.tableView.contentOffset.y-self.refreshControl.frame.size.height) animated:YES];

would make the spinner visible. But it wouldn't animate. The one thing I changed is the order of these two methods and everything worked:

[self.tableView setContentOffset:CGPointMake(0, self.tableView.contentOffset.y-self.refreshControl.frame.size.height) animated:YES];
[self.refreshControl beginRefreshing];

View more solutions

Comments

[Timur Zanagar]

Thanks - that achieved the effect I was after! I had to set the content offset back to 0, 0 once refreshing was finished also.

[Dmitry Shevchenko]

That's strange, in my tests, endRefreshing adjusts offset as needed

[Timur Zanagar]

It did sometimes, and not others. Could be related to the UINavigationController issue? Not sure :S

[simonthumper]

This is not true, I have two different UIViewControllers both of which have a contentOffset of 0 upon viewDidLoad and one of them correctly pulls down the refreshControl upon calling [self.refreshControl beginRefreshing] and the other does not :/

[Eric Baker]

BTW, if you're using auto layout, you can replace the line in the answer with this: [self.tableView setContentOffset:CGPointMake(0, -self.topLayoutGuide.length) animated:YES];

[Fábio Oliveira]

@EricBaker I believe that won't do. Not all UITableViewControllers show navigation bars. This would lead to a topLayoutGuide of length 20 and an offset too small.

[ZYiOS]

@EricBaker you can use: [self.tableView setContentOffset:CGPointMake(0, self.topLayoutGuide.length -self.refreshControl.frame.size.height) animated:YES];

[Gank]

This did solve my problem. But now I'm using SVPullToRefresh, how to pull it down programmatically?

[Kyle Robson]

@Gank I've never used SVPullToRefresh. Have you tried reading their docs? It seems quite obvious based on the docs that it can be pulled down programmatically: "If you’d like to programmatically trigger the refresh (for instance in viewDidAppear:), you can do so with: [tableView triggerPullToRefresh];" See: github.com/samvermette/SVPullToRefresh

[inix]

hi,Thank you a lot,I am also curious about the magic point (0, -64) I met when debugging.

[Igotit]

@inix 20 for status bar height + 44 for navigation bar height

[Diogo T]

Instead of -64 is better to use -self.topLayoutGuide.length

[Koen.]

Documentation doesn't say anything about displaying the control on beginRefreshing, only that its state changes. As I see it, it is to prevent to initiate the refresh action twice, so that might a programmatically called refresh would still be running, a user initiated action won't start another.

[Juan Boero]

Works for UITableView.

[Colin Basnett]

I would recommend putting sendActionsForControlEvents(UIControlEvents.ValueChanged) at the end of this function, otherwise the actual refresh logic logic will not be run.

[JoeGalind]

This is by far the most elegant way to do it. Including Colin Basnett's comment for better functionality. it can be used across the whole project by defining it once!

[user1366265]

Perfect! It was acting strange for me with the animation though, so I simply replaced it with scrollView.contentOffset = CGPoint(x: 0, y: scrollView.contentOffset.y - frame.height)

[Tudor]

I've merged this with the accepted answer as it's just an update.

[Jadamec]

I had to call beginRefreshing() in viewDidAppear instead of viewDidLoad, otherwise only the title was visible, not the spinning animation.

[Bilal]

This should fix the problem - (void)viewDidLoad { [super viewDidLoad]; dispatch_async(dispatch_get_main_queue(), ^{ [refreshControl beginRefreshing]; }); }

[carbonr]

Its the sendActions to trigger rx that makes this answer related to RxSwift incase anyone is wondering at first look

[nmdias]

I had to use the refreshControl instance from the tableViewController, not the tableView. Also, that setContentOffset didn't work for me targeting iOS10. This one works however: self.tableView.setContentOffset(CGPoint(x:0, y:self.tableView.contentOffset.y - (refreshControl.frame.size.height)), animated: true)

[Dru Freeman]

Just a general opinion... This needs to be radar'ed if it hasn't been fixed in 11. This seems like a oversight.

[Bassebus]

Of all the answers above, this was the only one I could get working on iOS 11.1 / xcode 9.1

[SinisterMJ]

@ColinBasnett : Adding that code (which is now sendActions(for: UIControlEvents.valueChanged)), results in an infinite loop...

[Marc Etcheverry]

I have noted issues with using the setContentOffset:animated method, so this solution worked for me.

[Morten Holmgaard]

Change the beginRefreshing() to the last line to fix problem with tintColor not respected on first show: stackoverflow.com/a/20383030/860488

[francybiga]

The asyncAfter is actually what makes the spinner animation work (iOS 12.3 / Xcode 10.2)

[jegadeesh]

calling send actions method is the only way it's working for me!

[Mishka]

triggers infinity loop