Weekly bite-sized screencasts on iOS development.

How Bézier Paths Work

Episode #149 | 12 minutes | published on 12/18/2014
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Have you ever wondered how bezier paths work? What are the control points, and how exactly do they affect the line? In this episode we'll build our own visualization of how a bézier path is constructed to help understand it better.

Function Composition with CI Filters

Episode #148 | 12 minutes | published on 12/11/2014
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We continue our example of CoreImage CIFilters, this time showing how function composition can facilitate working with filters a bit more flexible and chainable. Starting with the imperative, method-based approach, then gradually building towards a pattern that allows us to easily build filters functionally, swapping out the order, and changing around input parameters.

Core Image

Episode #147 | 14 minutes | published on 12/04/2014
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In this episode we take a look at Core Image, Apple's image framework for image effects on iOS and Mac OS X.

Vibrancy and Blur

Episode #146 | 11 minutes | published on 11/26/2014
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In this episode I revisit the blur technique we covered in episode 104 and re-implement it using iOS 8's Visual Effect view with UIBlurEffect and UIVibrancyEffect.

Share Extensions Part 2

Episode #145 | 12 minutes | published on 11/13/2014
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In this episode we continue our building of a share extension. This time we focus on performing the actual upload in the background, sharing a background session with our application through the App Group capability.

Share Extensions Part 1

Episode #144 | 19 minutes | published on 11/11/2014
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In this episode we create an application and share extension that lets us post to the Imgur API. We use a Framework to share API code between application and extension, and we leverage App Groups so that background sessions transfer across both as well.

Flat Map

Episode #143 | 25 minutes | published on 10/30/2014
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In this episode we cover a horribly named, yet fairly powerful concept called flat map. We'll use this technique to solve the problem we discovered last time dealing with Result<T> and having to use a switch statement everywhere.

Error Handling in Swift

Episode #142 | 12 minutes | published on 10/23/2014
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In this episode I talk about the pattern of communicating errors in Cocoa and how it can be improved by leveraging features in Swift. By introducing a Result type that is generic and applies to any type, it appears useful, however we run into some cumbersome use cases that will require further discussion.

Simulating Rope with UIKit Dynamics

Episode #141 | 23 minutes | published on 10/16/2014
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In this episode we use UIKit Dynamics to create something fun: Rope! By attaching many segments together with attachments, we can simulate the physics of a rope. We also discover the best way to move an object on the screen in conjunction with existing attachments.

UIAttachments

Episode #140 | 9 minutes | published on 10/09/2014
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In this episode we take another look at UIKit Dynamics, this time focusing on UIAttachmentBehavior, which allows you to create springs between elements to fix them in place or make them swing.

Today Extensions in iOS 8

Episode #139 | 12 minutes | published on 10/02/2014
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One of iOS 8's more powerful new features is App Extensions. With extensions we have a whole new range of possibilities. In this episode we'll focus on the Today Extension, which is a way to add a widget to Notification Center for quick access.

IBDesignable

Episode #138 | 14 minutes | published on 09/25/2014
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Finally iOS 8 and Xcode 6 are available and out of NDA and we can cover them on NSScreencast. There are tons of new features to cover, so today I'm just going to pick one: IBDesignable. With IBDesignable you can live preview your custom views so you don't have to stare at empty gray boxes in Interface Builder anymore. Interface Builder just got way more useful!

Fun with UIKit Dynamics

Episode #137 | 15 minutes | published on 09/18/2014
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In this episode we explore the powerful UIKit Dynamics that was introduced with iOS 7. With Dynamics you can simulate real world interactions between your views. We'll go over the basics of collision, gravity, rigid bounds, and leave off with an example of why you shouldn't use it to make games.

Clipping Paths

Episode #136 | 24 minutes | published on 09/11/2014
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In this episode we'll attempt to create the board for the game Connect Four. We'll leverage what we've learned about auto layout and create the connect four board constraints, then we'll draw the view. We have to draw it filled with a bunch of holes, so that we can see objects passing behind it. Using Core Graphics and clipping paths we can accomplish this effect.

Animating Constraints

Episode #135 | 15 minutes | published on 09/04/2014
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What good is a static layout? When specifying layout using constraints, we still need to provide transitions and other animations in our interfaces. We can do this quite easily by just animating between different sets of constraints.

Visual Format Language

Episode #134 | 13 minutes | published on 08/28/2014
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In this episode we explore Apple's Visual Format Language for building Auto Layout Constraints. While a bit strange at first glance, the Visual Format Language can really convey a lot of layout information in just a few characters in comparison to the manual building of NSLayoutConstraints can be.

Auto Layout in Code

Episode #133 | 18 minutes | published on 08/21/2014
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In this episode we take a look at how to set up auto layout constraints in code, rather than with Interface Builder / Storyboards. Whether you prefer to work in code or storyboards to lay you user interfaces, often times setting things up in code is required. You'll see how to use NSLayoutConstraint to fully specify a layout, and hopefully understand a bit more about how auto layout works.

Realm

Episode #132 | 12 minutes | published on 08/14/2014
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Realm is a new project that aims to replace Core Data and even SQLite for mobile app persistent storage needs. While an ambitious goal, I like seeing alternatives in this area, as Core Data is not always my favorite framework. In this episode we'll add Realm to a project and store a few rudimentary objects. We'll also see a quick way to query the data in the "realm".

Swift JSON Redux Part 2

Episode #131 | 10 minutes | published on 08/07/2014
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In this episode we wrap up our JSON parsing exploration in Swift by extending the decoding to work with arrays. Doing so cleans up the extraction code significantly.

Swift JSON Redux - Part 1

Episode #130 | 30 minutes | published on 07/31/2014
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In this episode we attempt to write a more idiomatic JSON Parsing framework leveraging Swift. To accomplish this we'll lean heavily on Swift's powerful enum features and apply a couple of custom operators to clean up syntax and reduce redundant code.