Tutorial

UIMotionEffect: Easily adding depth to your UI

One of the “delightful” features of iOS is the almost imperceptible UI effects they add to give the illusion of depth. One of the most under-appreciated features is UIMotionEffect, which ties the device’s gyroscope to your views to make them adapt to how the user moves their phone.

This can be seen throughout iOS, from your lock screen to your app icons in Springboard (the iOS app launcher). Done right, the user won’t consciously notice these views moving, but it helps set certain views apart from the rest of the app’s UI, helping them “pop” and be more noticeably separate from the rest of the app.

In this post I’ll go over what UIMotionEffects are, how they work, and will share my approach for simplifying how to add motion effects throughout your application.

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Styling your app using custom UIAppearance properties

UIAppearance is analogous to CSS for UIKit, while being compatible with both Interface Builder and traditional styling in code, without sacrificing performance. It’s a way of declaratively assigning UI style values to your views, without needing to manually tweak settings throughout your codebase. This makes it easy to define your app’s visual style centrally, which makes maintenance simpler when changes are necessary.

In this post, I’ll talk about how you can define your own custom UIAppearance properties in your views, allowing you to declaratively style your app giving you more flexibility and reusability.

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Docset Viewer v1.2 and how to customize iCloud backups

I’ve recently released version 1.2 of Docset Viewer, which fixes a number of bugs people experienced with the previous version. If you had problems with the previous release, please give this one a try.

One of the improvements I’ve added is the ability to customize whether or not you would like to back up your Docsets (which can get quite large) into iCloud. To keep with the instructional nature of this site, I’ll show you how you can do that in your own apps.
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Docset Viewer: Resuming large downloads with NSURLConnection

As I’ve shown in my previous post announcing Docset Viewer, I want this series of posts to be more than me talking about my new app. In keeping with the instructional nature of my site, I’m going to show you a few things that I did in my new app Docset Viewer and how I put it together. This time around I’m going to show how I use NSURLConnection for downloading large files, and even resuming them.

In Docset Viewer I’ve added the ability to download docsets directly from Atom feeds, either from custom URLs or from a pre-configured list of Apple’s available docsets. Since you may not be consistently connected to the Internet, it’s important to be able to download documentation packages incrementally, especially since they can be anywhere from 300MB to 500MB.Read More »Docset Viewer: Resuming large downloads with NSURLConnection

Building a static library with Jenkins

One of my pet peeves is Open Source iOS libraries distributed as just a collection of Objective-C classes, rather than being bundled as a static library. I know a lot of people prefer it that way, but from a maintainability standpoint it really doesn’t make much sense to me. So when I’m faced with another library I want to use that doesn’t have a static library readily available for it, I typically wrap it up in my own Xcode project, check it in to Github, and configure my Jenkins continuous integration build server to compile it for me.

I thought I’d walk you through the steps I go through to make this happen, so you can use this technique too.Read More »Building a static library with Jenkins

Using GCD and Blocks Effectively

With iOS 4.0 Apple introduced two new technologies to the iOS platform: Grand Central Dispatch, and blocks.  Simply put, it is to multi-threaded programming what fire is to a barbecue.  Sure you can do without it, but the end result is much better.

Despite all this, developers still seem to avoid using it. Some of the reasons for this, off the top of my head, could be backwards-compatibility for older versions of iOS, unfamiliarity with the funky syntax it uses, or simply a lack of practice.  The biggest thing I find however is a general misunderstanding about the importance of multi-threading among new developers, which was made worse by the difficulty of dealing with threads before blocks and GCD was released.

Fortunately there’s no reason to avoid multi-threaded programming in iOS, but before I dive into the specifics I’d like to point out just how important it is to use an asynchronous approach to development on iOS, or any mobile platform in general.
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Back to Basics: Using KVO

One of the things I like most about Apple’s iOS SDK is the consistent and easy-to-use API they provide.  Across all their different frameworks there’s a pattern at work that makes using their classes easy to understand.  This is due in part to the simplicity for configuring those objects.  In most cases you don’t need to call cryptic methods to setup or teardown classes.  If you want to change a label’s font, you just set a property.  If you want to add a new set of tabs to a UITabBarController, you simply have to assign an array of view controllers to the “viewControllers” property and away you go.
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Back to Basics: Simple UITableViews

Following up on my previous post in this series, I’m going to continue talking about beginner topics that I and many other developers take for granted. So for this entry in my “Back To Basics” series I’d like to talk about UITableViews, and how to simply and easily construct one without convoluted or confusing code.

This topic in particular is something I’ve struggled over in the past and never managed to find a clear example for how to get started. Certainly there’s a lot of examples to show how to construct a table view, how to create a datasource for it, and the basics for how to construct cells. But hardly anyone tells you how to easily and conveniently construct a menu of options without going down a maze of twisty passages.

So today I’ll show you how you can use simple “typedef” structures to describe and control a simple menu of options.

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Back To Basics: Positioning UIViews

These days I’ve been working on some fairly advanced iOS development techniques on my various projects: I’ve taught myself (badly) about Core Audio, I’m learning OpenGL, I’m developing a series of applications using Core Data, asynchronous parsing of JSON from a streaming HTTP connection, etc. It’s extremely fun and easy once you understand the basics.

What I tend to forget however is that you have to crawl before you can walk, and many people still struggle with some of the simpler techniques that I’ve learned that may not be so obvious, even when reading books or tutorials on Objective-C programming.

Since my previous series of articles on Core Animation (Part 1, Part 2, Part 3, Part 4) were so well received, I thought I’d do another series of articles titled “Back To Basics”.

So without further ado, I give you the first part in my series: Positioning UIViews.

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Animating Interfaces with Core Animation: Part 4

This is the fourth in a series of posts I’m writing on animating iOS interfaces using Core Animation. In the first post I created a planetary orbit demo using nested CALayer objects. The second post showed how to dress up a UI by animating an image. The third post shows how you can trigger animations in response to button actions.

This post will show how you can create the beginnings of a full game using Core Animation combined with CAShapeLayer and UIBezierPath objects.

Read on to see more

Read More »Animating Interfaces with Core Animation: Part 4