MarqueeLabel

Description

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.

Setup

NOTE: The labelize feature may act slightly differently than in previous versions. Check out the Special Notes section below.

MarqueeLabel uses ARC.

Setup steps:

  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.

Usage

MarqueeLabel supports moving the label at either a defined rate (points per second) or duration (seconds). The animation curve can also be defined, and defaults to UIViewAnimationOptionCurveEaseInOut. It also features a variable-length 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.

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:

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

Special Notes

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 pausing scrolling with the label at the "home" location, use the holdScrolling property instead.

Modal View Controllers

Currently I haven't found a clean way to auto-restart MarqueeLabels upon the dismissal of a modal view controller. See the Important Animation Note section below.

Even More

Check out MarqueeLabel.h for more features, with explanations in the comments there:

  • Scrolling direction (left->right, right->left, and continuous)
  • Label edge fades
  • Pausing/unpausing mid-animation scrolling of the label
  • Tap to scroll once

Important Animation Note

MarqueeLabel is based on UIView animations, 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 viewControllerDidAppear: is intended to be called when your UIViewController appears or is revealed (presenting a modal view controller pauses repeating animations!).

controllerLabelsShouldLabelize: and controllerLabelsShouldAnimate: are more 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

  • Any ideas?

About

Charles Powell

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