IOS Common faces trying to summarize 2

1. Please describe the difference between storyboard and xib?

In a project, you can have multiple xib files, a xib file that corresponds to a view class controller, and multiple views. However, using

Storyboard, a project requires only one master storyboard file, so in the case of multiple attempts to control the

Storyboard management is more convenient, and storyboard can also describe the navigation between interfaces

Relationship.

2. Please list the singleton classes in the iOS system?

UIApplication (Application instance)

Nsuserdefault (Application settings)

Nsfilemanager (file Management)

Nsurlcache (Request cache)

Nsnotificationcenter (Message Center)

Nshttpcookiestorage (Application Cookies Pool)

3. Please outline your understanding of the synchronous/asynchronous request data?

1. The synchronization request can request data from the network, once the synchronization request is sent, the program will stop interacting with the user until the server returns data

Before you can proceed to the next step.

2. Asynchronous requests do not block the main thread, but create a new thread to operate, and after the user makes an asynchronous request, the UI can still be

Operation, the program can continue to run.

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IOS Common faces trying to summarize 2