iOS 4 Programming Cookbook: Solutions & Examples for iPhone, iPad, and iPod touch Apps [Repost]

You can build a variety of amazing apps on the iOS platform—and every one of them presents a unique set of problems. With the recipes in this cookbook, you will go beyond theory to solve the vexing, real life issues you are likely to face when creating apps for the iPhone, iPad, or iPod Touch. Each recipe provides a clear solution and sample code that you can use right away.
You will find solutions for working with development frameworks in iOS SDK 4 and technologies such as Cocoa, Objective-C, Xcode, and Interface Builder. Whether you have a little or a lot of experience with iOS development, you’ll find the help you need for every phase of the process, from initial idea to completed project.

Work with Objective-C classes, objects, properties, delegates, and memory management
Construct a user interface with gesture recognizers
Develop location-aware applications with the Map Kit and Core Location APIs
Build apps that play audio and video, manage calendars and events, access contacts and groups, or tap into the Photo Library
Use the Core Motion framework to access the accelerometer and gyroscope
Maintain persistent storage for iOS apps with the Core Data framework
Create multitasking-aware apps that let users leave and return without losing their place