-Documents
-Library
    -Caches
    -References
-tmp

获取根目录

真机和模拟器路径可能不同，待验证

NSString *sandBoxRootDir = NSHomeDirectory();

获取Documents路径

// NSSearchPathForDirectoriesInDomains返回的是一个数组，但这里第一个参数是NSDocumentDirectory，返回数组里只有一个，所以用了lastObject, 也可以用[paths objectAtIndex:0]
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths lastObject];

获取Library路径

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
NSString *libraryDirectory = [paths lastObject];

获取Caches路径

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *cachesDirectory = [paths lastObject];    

Preferences路径

通过NSUserDefaults存取数据

获取tmp路径

NSString *tmpDirectory = NSTemporaryDirectory();