Grand Central Dispatch (GCD)多线程。
UIKit Framework Reference
Photos Framework And PhotosUI Framework。
Create a view-controller-based user interface for composing email messages. Use it in cases where you want the user to be able to create email messages without leaving your application.
Contacts And ContactsUI
Use the Contacts framework to gain access to the centralized database for storing a user's contacts. The database is used by apps such as Mail and Messages to present information about known and unknown persons.
Use the Contacts UI framework to display the data contained in the Contacts database. This framework provides a graphical interface to gain access to users' contacts.
Read and write most image file formats with the Image I/O framework. This C-based framework also supports color management and access to image metadata.
Enable web-based views and services in your app with the Safari Services framework.
Display view-based previews of items with the Quick Look framework.
Send requests to a supported social networking service to perform operations on behalf of your users, integrating their social networking accounts with your app.
Manage the user's external accounts using the Accounts framework. You can also use this framework to simplify the authorization process when using external APIs, such as the Twitter API.
Access the advertising identifier and a flag indicating whether the user has chosen to limit ad tracking.
Receive and handle accelerometer and other motion events with the Core Motion framework.
Index the content in your app and enable users to deep-link to that content from Spotlight and Safari search results with the Core Spotlight framework. Core Spotlight is designed for apps that handle persistent user data, such as documents, photos, and other types of content created by or on behalf of users. Use Core Spotlight APIs to add, retrieve, update, and delete items that represent searchable app content.
Gain access to cellular telephone call status and cellular service provider information with the Core Telephony framework.
Use the Foundation framework for the "nuts and bolts" classes for Objective-C programming. This framework provides essential Objective-C classes, most importantly the root class, NSObject, which defines basic object behavior. It includes classes for objects representing basic data types, collections, and operating-system services. Foundation also introduces several design patterns and mechanisms that contribute to the robustness and efficiency of Objective-C programs. Along with UIKit, the Foundation framework provides the basic tools and infrastructure you need to implement graphical, event-driven iOS applications.