NSUserDefaults enables quick access to small data

Usage reason: the data is single, small, and the code is concise.

I. Position of NSUserDefaults Data Storage

NSUserDefaults is used to save iPhone program data, which is very convenient to use.
So where will the data be stored? Stored in a plist file.
This file is located in <UUID for your App> LibraryPreferences <your App "s bundle ID>. plist

2. supported data types
NSUserDefaults only supports: NSString, NSNumber, NSDate, NSArray, NSDictionary.

Iii. Fetch
For example:
Objective-c code
// Read and save the number of times users use the software

NSUserDefaults * ud = [NSUserDefaults standardUserDefaults];

NSNumber * count = [ud objectForKey: @ "times"];

Iv. Storage

Example:
Objective-c code
Int t = [count intValue] + 1;

[Ud setObject: [NSNumber numberWithInt: t] forKey: @ "times"];