You need to watch this video

Playgrounds are awesome, Apple has made amazing job with Xcode 6 and Playgrounds were the icing on the cake.

They have multitude of use cases, eg.

• prototype custom algorithms
• design custom UI
• learn the language or explore different API

But since most of us still need to write Objective-C I give you

Features:

• Faster than Swift playgrounds (a lot)
• Extra controls for tweaking:
• Adjustable values
• Auto-animated values
• Buttons
• IDE agnostic, once you run it, you can modify the code even from vim.
• Full iOS simulator and access to all iOS features, so you can prototype production ready code.
• Nice DSL for rapid prototyping
• CocoaPods support, so you can add it to existing projects to experiment
• Open source, anyone can contribute to make them better!

It’s just a start.

First, let’s establish naming:

• Timeline is a place where you have snapshots and controls.
• Worksheet is a place where you can add views / controls and have interaction with them. You can use all the stuff you’d normally use with iOS like UIGestureRecognizers etc.
• Tick counter - number of times the code changes have been loaded, multiply by the time it takes to compile + load your project and you see how much time you saved.

KZPShow(obj)

• CALayer
• UIView
• UIBezierPath
• CGPathRef
• CGImageRef
• UIImage
• NSString, with format or without
• id

You can implement custom debug image:

- (UIImage*)kzp_debugImage;

If you have already implemented - (id)debugQuickLookObject that returns any of types supported by the KZPShow, you don’t need to do anything.

• Button

KZPAction(@"Press me", ^{
// Magic code
})

• Adjusters

KZPAdjustValue(scale, 0.5f, 1.0f) //- for floats
KZPAdjustValue(position, 0, 100) //- for integers

• Also available as block callbacks KZPAdjust

• Block animation callback, wrap the changes you want to be dynamic in them.

KZPAnimate(CGFloat from, CGFloat to, void (^block)(CGFloat));
KZPAnimate(void (^block)());

• Auto-animated values, defines new variable and automatically animates them. AR -> AutoReverse

KZPAnimateValue(rotation, 0, 360)
KZPAnimateValueAR(scale, 0, 1)

Instead of using instance variables / properties for KZPlayground class (you are fine to use them for normal classes that you create as part of playground), you should store playground specific variables that you need to reference between playground methods, eg. view you want to pan with UIPanGestureRecognizer inside transientObjects dictionary.

self.transientObjects[@"pannableView"] = view;

Implement setup method and use normal instance variables to store data you don't want to change on code change. eg. if you need to do some expensive operation.

Snapshots recorded during setup will persist in timeline.

- (void)setup
{
	self.data = [self fetchBigDataSet];
}

KZPlayground is distributed as a CocoaPod: pod 'KZPlayground' so you can either add it to your existing project or clone this repository and play with it.

Remember to not add playgrounds in production builds (easy with new cocoapods configuration scoping).

Once you have pod installed, you need to create your playground, it’s simple:

1. Subclass KZPPlayground
2. Implement run method
3. Conform to KZPActivePlayground protocol

• You can have many playgrounds in one project, but only one should be marked as KZPActivePlayground. It will be automatically loaded.

4. present [KZPPlaygroundViewController playgroundViewController]

To apply your changes you have 2 approaches:

1. Xcode/Appcode you can use cmd/ctrl + x (done via dyci plugin) while you are modifying your code.
2. (My Preferrence) Automatic on file save (IDE agnostic) using kicker gem in terminal: (N.B. you need to have the kicker gem installed, see below)

kicker -sql 0.016 FOLDER_WITH_SOURCE_FILES

in case of Example project you'd call kicker from inside the project root folder (one containing Example and Pod)

kicker -sql 0.016 Example

This will react to all changes in .m files and reload your playground.

KZPlayground is powered by Dyci code injection tool, you only need to install it once on your machine (You’ll need to reinstall it on Xcode updates):

git clone https://github.com/DyCI/dyci-main.git
cd dyci-main/Install/
./install.sh

In order to use the kicker gem, you need to install it as follows:

(sudo) gem install kicker

• Recompilation of Xib
• Recompilation of Storyboards
• Integrate graph displays.
• Resizable timeline/worksheet splitter.
• Nicer visualisations for Arrays && Dictionaries.

Pull-requests and ideas for features are welcomed and encouraged.

It took me around 12h to get from idea to release so the code is likely to change before 1.0 release.

If you'd like to get specific features I'm available for iOS consulting.

KZPlayground is available under the modified MIT license. See the LICENSE file for more info.

Krzysztof Zablocki, [email protected]

Follow me on twitter.

Check-out my blog or GitHub profile for more cool stuff.

SceneKit example code has been taken from David Ronnqvist upcoming SceneKit book, recommended.