Overview

MarqueeLabel is a UILabel subclass adds a scrolling marquee effect when the text of the label outgrows the available width. The label scrolling direction and speed/rate can be specified as well. All standard UILabel properties (where it makes sense) are available in MarqueeLabel and it behaves just like a UILabel.

How To Get Started

  1. Clone MarqueeLabel from Github, and check out the demo project.
  2. Read the MarqueeLabel CocoaDocs documentation.
  3. Take a look at the special notes section to be aware of any gotchas.
  4. Drop in MarqueeLabel as a replacement to your lengthy UILabels!
  5. Help out with bug fixes and new features.

MarqueeLabel v2.0.0

MarqueeLabel v2.0.0 makes some important changes! Check out the release notes for v2.0.0 to understand what this means for your app!

Installation with Cocoapods

CocoaPods is a dependency manager for Objective-C, which automates and simplifies the process of using 3rd-party libraries in your projects.

Podfile

If you use CocoaPods, you can install the latest release version of MarqueeLabel by adding the following to your project's Podfile:

pod 'MarqueeLabel'

Manual Installation

  1. Add MarqueeLabel.h and MarqueeLabel.m to your project.
  2. Add QuartzCore.framework to your project frameworks.
  3. Import MarqueeLabel.h and replace your UILabels with MarqueeLabels as needed.

Note: MarqueeLabel uses ARC.

Usage

MarqueeLabel supports scrolling the label, at either a defined rate (points per second) or over a duration (seconds), whenever the length of the label's text exceeds the space available given the label's frame. There are several options for the marquee type, and the default is MLContinuous (which looks just like what Apple typically uses). The animation curve of this scroll can be defined, and defaults to UIViewAnimationOptionCurveLinear. MarqueeLabel also features an optional fade at the left and right side view borders, in order to fade the label text into the background rather than simply being chopped off.

To use MarqueeLabel, replace:

UILabel *lengthyLabel = [[UILabel alloc] initWithFrame:labelCGRectFrame];

With:

MarqueeLabel *scrollyLabel = [[MarqueeLabel alloc] initWithFrame:labelCGRectFrame duration:8.0 andFadeLength:10.0f];

This creates a MarqueeLabel that will scroll across its content in 8.0 seconds, and adds 10.0 point long fade at the left and right boundaries.

If you'd rather have a label that scrolls at a specific rate (points per second), instead of completing the scroll in a specific time frame, you can use this instead:

MarqueeLabel *scrollyLabel = [[MarqueeLabel alloc] initWithFrame:labelCGRectFrame rate:50.0 andFadeLength:10.0f];

Even More

Check out the MarqueeLabel documentation for more about all the features, including:

  • Bulk-manipulation class methods to conveniently restart, pause, and unpause all labels in a view controller
  • Scrolling direction: left->right, right->left, and continuous looping (both left and right)
  • Label edge fades
  • Pausing/unpausing mid-animation scrolling of the label
  • Tap to scroll

Special Notes

Automatic Scrolling

MarqueeLabel tries its best to automatically begin scrolling when appropriate, but sometimes the way your view/view controller appears onscreen can trip it up.

To combat this, you can try:

  • Using the restartLabel instance method to "manually" start scrolling on a MarqueeLabel
  • Try using the bulk manipulation class methods - but note that these don't currently play well with UIViewController containment. You'll need to pass them the lowest UIViewController in your heirarchy.

Labelize

Using the labelize feature will cause a MarqueeLabel to act like a normal UILabel - including the line break mode you've set. This could cause the ellipsis (...) to appear if you leave the lineBreakMode property as the default NSLineBreakByTruncatingTail.

If you simply wish to pause scrolling with the label at the "home" location, set the holdScrolling property to YES instead. The automatic scroll animation won't restart until you set holdScrolling back to NO.

Modal View Controllers

Sometimes MarqueeLabel will fail to auto-restart upon the dismissal of a modal view controller or other view controller which blocks the view of your view controller. It's not always necessary, as sometimes the scroll animations will continue happily in the background. However, see the Important Animation Note section below.

Important Animation Note

MarqueeLabel is based on Core Animation, which does cause some problems when views appear and disappear and the repeating animation is stopped by iOS and does not automatically restart.

To combat this, MarqueeLabel provides a few class methods that allow easy "restarting" of all MarqueeLabels associated with a UIViewController. Specifically, the class method restartLabelsOfController: should be called by your view controller (which passes in self for the controller parameter`) when it is revealed or about to be revealed. Keep in mind that presenting a modal view controller can pause repeating UIView animations in the controller that is being covered!

controllerLabelsShouldLabelize: and controllerLabelsShouldAnimate: are for convienience, allowing labelizing and re-animating all labels of a UIViewController. Labelizing can be useful for performance, such as labelizing all MarqueeLabels when a UITableView/UIScrollView starts scrolling.

Todo

  • Ideas?

About

Charles Powell

Give me a shout if you're using this in your project!