iOS沙盒使用总结

1沙盒机制

iPhone对于安装在上面的应用程序只能在为该改程序创建的文件系统中读取文件，不可以去其它地方访问，这个区域就叫做沙盒。所有和该程序有关的文件都保存在这个独立，安全，封闭的空间（或者目录）。

2沙盒路径

通过代码可以在模拟器或者真机上找到路径，查看目录

在该目录下有四个文件夹Documents，Library（里边有Caches和Preferences），SystemData和tmp文件夹。

Documents目录

用于写入应用相关数据文件的目录，在ios中写入这里的文件能够与iTunes共享并访问，存储在这里的文件会自动备份到云端.

Library/Preferences

这保存应用程序的所有偏好设置iOS的Settings(设置)，我们不应该直接在这里创建文件，

而是需要通过NSUserDefault这个类来访问应用程序的偏好设置。

Library/Caches

iTunes不会对这个目录的内容进行备份,一般存储的是缓存文件，例如图片视频等，此目录下的文件不会再应用程序退出时删除。

tmp

临时文件目录，在程序重新运行的时候，和开机的时候，会清空tmp文件夹。

3如何获取路径

 获取沙盒路径用的方法NSSearchPathForDirectoriesInDomains。

   NSArray<NSString *> *NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory directory, NSSearchPathDomainMask domainMask, BOOL expandTilde);


typedef NS_ENUM(NSUInteger, NSSearchPathDirectory) {
    NSApplicationDirectory = 1,             // supported applications (Applications)
    NSDemoApplicationDirectory,             // unsupported applications, demonstration versions (Demos)
    NSDeveloperApplicationDirectory,        // developer applications (Developer/Applications). DEPRECATED - there is no one single Developer directory.
    NSAdminApplicationDirectory,            // system and network administration applications (Administration)
    NSLibraryDirectory,                     // various documentation, support, and configuration files, resources (Library)
    NSDeveloperDirectory,                   // developer resources (Developer) DEPRECATED - there is no one single Developer directory.
    NSUserDirectory,                        // user home directories (Users)
    NSDocumentationDirectory,               // documentation (Documentation)
    NSDocumentDirectory,                    // documents (Documents)
    NSCoreServiceDirectory,                 // location of CoreServices directory (System/Library/CoreServices)
    NSAutosavedInformationDirectory API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0)) = 11,   // location of autosaved documents (Documents/Autosaved)
    NSDesktopDirectory = 12,                // location of user's desktop
    NSCachesDirectory = 13,                 // location of discardable cache files (Library/Caches)
    NSApplicationSupportDirectory = 14,     // location of application support files (plug-ins, etc) (Library/Application Support)
    NSDownloadsDirectory API_AVAILABLE(macos(10.5), ios(2.0), watchos(2.0), tvos(9.0)) = 15,              // location of the user's "Downloads" directory
    NSInputMethodsDirectory API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0)) = 16,           // input methods (Library/Input Methods)
    NSMoviesDirectory API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0)) = 17,                 // location of user's Movies directory (~/Movies)
    NSMusicDirectory API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0)) = 18,                  // location of user's Music directory (~/Music)
    NSPicturesDirectory API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0)) = 19,               // location of user's Pictures directory (~/Pictures)
    NSPrinterDescriptionDirectory API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0)) = 20,     // location of system's PPDs directory (Library/Printers/PPDs)
    NSSharedPublicDirectory API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0)) = 21,           // location of user's Public sharing directory (~/Public)
    NSPreferencePanesDirectory API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0)) = 22,        // location of the PreferencePanes directory for use with System Preferences (Library/PreferencePanes)
    NSApplicationScriptsDirectory NS_ENUM_AVAILABLE(10_8, NA) = 23,      // location of the user scripts folder for the calling application (~/Library/Application Scripts/code-signing-id)
    NSItemReplacementDirectory API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0)) = 99,	    // For use with NSFileManager's URLForDirectory:inDomain:appropriateForURL:create:error:
    NSAllApplicationsDirectory = 100,       // all directories where applications can occur
    NSAllLibrariesDirectory = 101,          // all directories where resources can occur
    NSTrashDirectory API_AVAILABLE(macos(10.8), ios(11.0)) API_UNAVAILABLE(watchos, tvos) = 102             // location of Trash directory

};

typedef NS_OPTIONS(NSUInteger, NSSearchPathDomainMask) {
    NSUserDomainMask = 1,       // user's home directory --- place to install user's personal items (~)
    NSLocalDomainMask = 2,      // local to the current machine --- place to install items available to everyone on this machine (/Library)
    NSNetworkDomainMask = 4,    // publically available location in the local area network --- place to install items available on the network (/Network)
    NSSystemDomainMask = 8,     // provided by Apple, unmodifiable (/System)
    NSAllDomainsMask = 0x0ffff  // all domains: all of the above and future items
};

获取各个目录的方法

  NSString *path = NSHomeDirectory();
    NSLog(@"沙盒目录 %@",path);
    
    // 获取沙盒主目录路径
    NSString *homeDir = NSHomeDirectory();
     NSLog(@"沙盒主目录路径是%@",homeDir);
    // 获取Documents目录路径
    NSString *docDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
    NSLog(@"Documents目录路径是%@",docDir);
    // 获取Library的目录路径
    NSString *libDir = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) lastObject];
    NSLog(@"Library的目录路径是%@",docDir);
    // 获取Caches目录路径
    NSString *cachesDir = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject];
    NSLog(@"Caches目录路径是%@",docDir);
    // 获取tmp目录路径
    NSString *tmpDir =  NSTemporaryDirectory();
    NSLog(@"tmp目录路径是%@",docDir);