Cocoa

iPhone Developer Tips Visitor Stats:
126,691 Pageviews and 94,296 visitors in the past 30 days.



Introduction to Protocols

What follows is a quick introduction to working with protocols. This is good background information to understand as protocols are common in various Cocoa frameworks. A protocol is means to define a list of required and/or optional methods that a class implements. If a class adopts a protocol, it must implement all required methods in [...]

Cocoa

Basics of Notifications

What follows is a brief guide to working with Notifications in Cocoa. I’ll cover the basics, including registering an observer and posting notifications, just enough to start using notifications in your iPhone apps. There is an instance of NSNotificationCenter available to every running iPhone application. This class acts as an intermediary to facilitate communication between [...]

Cocoa

Single, Double and Triple Taps

If you need to tinker with the threshold (time between clicks) when working with single, double and triple taps on the touch screen, one approach for this follows. What follows is a short example that demonstrates how you can manage the delay between taps.

Cocoa

Get Application Name

If you ever need to get the name of your application in code, for example, to display the application name across a navigation bar, it’s as near as the bundle for your application. The code to get the name is as simple as this: [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleName"]; The breakdown is as follows:

Cocoa

NSNumber versus NSInteger

If you’ve ever found yourself scratching your head thinking “now which one should I be using, NSNumber or NSInteger?” the short summary below should help. NSInteger is nothing more than a synonym for a long integer. What follows is how NSInteger is defined:

Cocoa

Read and Write User Preferences

Reading and writing user preferences within iPhone applications is surprisingly easy given the NSUserDefaults class does most all the work for you. What follows is a short example to show how you can read/write two values, a boolean and an integer. The example assumes you want to save state as to whether a user wants [...]

Cocoa

Launching Your Own Application via a Custom URL Scheme

One of the coolest features of the iPhone SDK is an application’s ability to “bind” itself to a custom URL scheme and for that scheme to be used to launch itself from either a browser or from another application on the iPhone. Creating this kind of binding is so simple, its almost criminal not to [...]

Cocoa

Launching Other Apps within an iPhone Application (Part 2)

To continue on the types of URL Schemes that are supported by the iPhone (see Part 1); today I will show you how to: Launch YouTube “Deep Link” to content in iTunes

Cocoa

How to Mask an Image

Masking an image enables a developer to create images with irregular shapes dynamically. Masking is often used to create a user interface that is more compelling and less boring. Take for example the following example …

Cocoa

Date Formatter Examples – Take 3: Date from String

While working on an iPhone application recently, I needed to convert a date read from an XML stream that was in the following format: 20081122 to a nicely formatted string for display on the device: Saturday November 22, 2008.

Cocoa, Date and Time

“Default.png” the secret of the load screen …

Ever wondered how all of the applications on your iPhone seem to show a loading screen or “boilerplate” as soon as the icon is touched and wondered how they get the image to appear quickly? Well the secret is in the presence of a file in your application called Default.png.

Cocoa

Date Formatter Examples – Take 2: Format Strings

In the first post on working with dates several of the examples use the “old style” date format syntax. The examples work, however, I want to show an additional example that uses the ICU (International Components for Unicode) library for format strings.

Cocoa, Date and Time

How to “unfreeze” your iPhone Application

Have you ever found yourself stumped because your application locks up but doesn’t seem to crash or in any other way indicate that there is an error? If you have, then you are likely the victim of a common problem that can occur when you attempt to make certain changes to the UI outside of the main thread. Put more technically … you are doing something that is not “Thread Safe”.

Cocoa

Date Formatter Examples – Take 1: NSDateFormatter

Sometimes all you’re really looking for is a basic chunk of code to get something done. For example, I was working on an application yesterday and needed to display the current date in text format: October 29, 2008. A simple concept for sure, however, with the many nuances of date formatters, it takes some time [...]

Cocoa, Date and Time

How to Prevent iPhone from Sleeping

The automatic sleep timer is one of the ways the iPhone saves power. If the screen isn’t touched for a certain amount of time, it dims the screen and eventually turns it off. Although you should leave the timer on, there are times when this is not what you want (games are a good example). [...]

Cocoa