Skip to content

Instantly share code, notes, and snippets.

View chrismiles's full-sized avatar

Chris Miles chrismiles

View GitHub Profile
@nicklockwood
nicklockwood / Hacking UIView Animation Blocks.md
Last active August 24, 2024 17:08
This article was originally written for objc.io issue 12, but didn't make the cut. It was intended to be read in the context of the other articles, so if you aren't familiar with concepts such as CALayer property animations and the role of actionForKey:, read the articles in that issue first.

Hacking UIView animation blocks for fun and profit

In this article, I'm going to explore a way that we can create views that implement custom Core Animation property animations in a natural way.

As we know, layers in iOS come in two flavours: Backing layers and hosted layers. The only difference between them is that the view acts as the layer delegate for its backing layer, but not for any hosted sublayers.

In order to implement the UIView transactional animation blocks, UIView disables all animations by default and then re-enables them individually as required. It does this using the actionForLayer:forKey: method.

Somewhat strangely, UIView doesn't enable animations for every property that CALayer does by default. A notable example is the layer.contents property, which is animatable by default for a hosted layer, but cannot be animated using a UIView animation block.

#!/bin/sh
find=`find /Applications /Applications/Utilities -maxdepth 2 -name '*.app' -exec echo \{\} \;`
#echo $find
IFS=$'\n'
apps=($find)
total=${#apps[*]}
echo "Checking $total applications..."
echo "The following applications will break in Gatekeeper on 10.9.5 and Yosemite:"
count=0
@jspahrsummers
jspahrsummers / GHRunLoopWatchdog.h
Created January 28, 2015 20:50
A class for logging excessive blocking on the main thread
/// Observes a run loop to detect any stalling or blocking that occurs.
///
/// This class is thread-safe.
@interface GHRunLoopWatchdog : NSObject
/// Initializes the receiver to watch the specified run loop, using a default
/// stalling threshold.
- (id)initWithRunLoop:(CFRunLoopRef)runLoop;
/// Initializes the receiver to detect when the specified run loop blocks for
@smileyborg
smileyborg / Xcode7Macros.h
Last active May 26, 2020 12:08
Backwards compatible macros for Objective-C nullability annotations and generics
/**
* The following preprocessor macros can be used to adopt the new nullability annotations and generics
* features available in Xcode 7, while maintaining backwards compatibility with earlier versions of
* Xcode that do not support these features.
*/
#if __has_feature(nullability)
# define __ASSUME_NONNULL_BEGIN NS_ASSUME_NONNULL_BEGIN
# define __ASSUME_NONNULL_END NS_ASSUME_NONNULL_END
# define __NULLABLE nullable