Important note if your project doesn’t use ARC: you must add the -fobjc-arc compiler flag to SVPullToRefresh.m in Target Settings > Build Phases > Compile Sources.

SVPullToRefresh

SVPullToRefresh allows you to easily add pull-to-refresh and/or infinite scrolling functionalities to any UITableView subclass with only 1 line of code. Instead of depending on delegates and/or subclassing UIViewController, SVPullToRefresh extends UIScrollView with the following 2 methods:

- (void)addPullToRefreshWithActionHandler:(void (^)(void))actionHandler;
- (void)addInfiniteScrollingWithActionHandler:(void (^)(void))actionHandler;

Installation

• Drag the SVPullToRefresh/SVPullToRefresh folder into your project.
• Add the QuartzCore framework to your project.
• #import "SVPullToRefresh.h"

Usage

(see sample Xcode project in /Demo)

Adding pull to refresh to your table view

[tableView addPullToRefreshWithActionHandler:^{
    // refresh data
    // call [tableView.pullToRefreshView stopAnimating] when done
}];

If you’d like to programmatically trigger the refresh (for instance in viewDidLoad), you can do so with:

[tableView.pullToRefreshView triggerRefresh];

You can temporarily hide/disable pull to refresh by setting the showsPullToRefresh property:

tableView.showsPullToRefresh = NO;

Customization

The pullToRefreshView view can be customized using the following properties:

@property (nonatomic, strong) UIColor *arrowColor;
@property (nonatomic, strong) UIColor *textColor;
@property (nonatomic, readwrite) UIActivityIndicatorViewStyle activityIndicatorViewStyle;

You can access these properties through your scroll view’s pullToRefreshView property.

For instance, you would set the arrowColor property using:

tableView.pullToRefreshView.arrowColor = [UIColor whiteColor];

Showing a “Last Updated” label

If you think it’s in the user’s interest to display the date of the last refresh, you can set the lastUpdatedDate property of pullToRefreshView:

tableView.pullToRefreshView.lastUpdatedDate = nil; // will display "Last Updated: Never"
tableView.pullToRefreshView.lastUpdatedDate = [NSDate date]; // will display "Last Updated: 4/30/12 11:53 AM"

You can also configure how the date is displayed by setting the dateFormatter property:

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
dateFormatter.dateStyle = NSDateFormatterLongStyle;
dateFormatter.timeStyle = NSDateFormatterNoStyle;
tableView.pullToRefreshView.dateFormatter = dateFormatter;

Adding infinite scrolling to your table view

[tableView addInfiniteScrollingWithActionHandler:^{
    // add data to data source, insert new cells into table view
}];

You can temporarily hide/disable infinite scrolling by setting the showsInfiniteScrolling property:

tableView.showsInfiniteScrolling = NO;

Customization

The infiniteScrollingView (a UIView subclass) can be customized using the following properties:

@property (nonatomic, readwrite) UIActivityIndicatorViewStyle activityIndicatorViewStyle;

You can access these properties through your scroll view’s infiniteScrollingView property.

Under the hood

SVPullToRefresh extends UIScrollView by adding new public methods as well as a dynamic properties (thanks @seb_morel!). It uses key-value observing to track the scrollView’s contentOffset, which removes the need for the view to be linked to the UIScrollViewDelegate protocol.

Credits

SVPullToRefresh is brought to you by Sam Vermette and contributors to the project. If you have feature suggestions or bug reports, feel free to help out by sending pull requests or by creating new issues. If you’re using SVPullToRefresh in your project, attribution would be nice.

Big thanks to @seb_morel for his Demistifying the Objective-C runtime talk, which permitted the level of abstraction found in SVPullToRefresh.

Hat tip to Loren Brichter for inventing such a great UI mechanism.