About iOS App Architecture
需求：
understanding how your app interacts with the system and what it must do to make those interactions happen smoothly
app architecture and shows you how to implement many app-level features.
需要：
app-creation process from start to finish, showing you how to create a simple app and get it running quickly.
一瞥：
1、Apps Are Expected to Support Key Features－－－－app的功能信息、配置数据、具体资源
Providing the Required Resources 、Supporting User Privacy(保护用户隐私 )、Internationalizing Your App
Required device capabilities－－－－－ Declaring the Required Device Capabilities.
An information property-list file－－－edit--- Information Property List Key Reference-------Info.plist file is a structured file-----Using URL Schemes to Communicate with Apps.---Document-Based App Programming Guide for iOS.
Apps should provide usage descriptions for certain app features. Whenever there is a privacy concern about an app accessing a user’s data or a device’s capabilities, iOS frameworks prompt the user and request permission for your app to use the feature. Apps that use these features should provide privacy usage descriptions that explain what your app plans to do with the corresponding data.
* Apps can declare any custom URL schemes they support. Use the URL Types section of the Info tab to specify the custom URL schemes that your app handles. Apps can use custom URL schemes to communicate with each other. For more information about how to implement support for this feature, see Using URL Schemes to Communicate with Apps.Apps should provide usage descriptions for certain app features. Whenever there is a privacy concern about an app accessing a user’s data or a device’s capabilities, iOS frameworks prompt the user and request permission for your app to use the feature. Apps that use these features should provide privacy usage descriptions that explain what your app plans to do with the corresponding data.
* Apps that define custom document types must declare those types. Use the Document Types section of the Info tab to specify icons and UTI information for the document formats that you support. The system uses this information to identify apps capable of handling specific file types. For more information about adding document support to your app, see Document-Based App Programming Guide for iOS.Declare your app’s required capabilities in the Info tab. The Required device capabilities section contains information about the device-level features that your app requires to run. The App Store uses the information in this entry to determine the capabilities of your app and to prevent it from being installed on devices that do not support features your app requires.
icons
launch images
2、Apps Follow Well-Defined Execution Paths －－－状态转换
3、Apps Must Run Efficiently in a Multitasking Environment－－－后台运行、状态转换
4、Communication Between Apps Follows Specific Pathways
5、Performance Tuning is Important for Apps－－－－power cost
