android 沙盒 ios,iOS开发关于沙盒

每个iOS程序都有一个独立的文件系统(存储空间)，而且只能在对应的文件系统中进行操作，此区域被称为沙盒。应用必须待在自己的沙盒里，其他应用不能访问该沙盒。所有的非代码文件都要保存在此，例如属性文件plist、文本文件、图像、图标、媒体资源等。

iOS app 沙盒目录结构

沙盒中相关路径

AppName.app 应用程序的程序包目录，包含应用程序的本身。由于应用程序必须经过签名，所以不能在运行时对这个目录中的内容进行修改，否则会导致应用程序无法启动。

Documents/ 保存应用程序的重要数据文件和用户数据文件等。用户数据基本上都放在这个位置(例如从网上下载的图片或音乐文件)，该文件夹在应用程序更新时会自动备份，在连接iTunes时也可以自动同步备份其中的数据。

Library：这个目录下有两个子目录,可创建子文件夹。可以用来放置您希望被备份但不希望被用户看到的数据。该路径下的文件夹，除Caches以外，都会被iTunes备份.

Library/Caches: 保存应用程序使用时产生的支持文件和缓存文件(保存应用程序再次启动过程中需要的信息)，还有日志文件最好也放在这个目录。iTunes 同步时不会备份该目录并且可能被其他工具清理掉其中的数据。

Library/Preferences: 保存应用程序的偏好设置文件。NSUserDefaults类创建的数据和plist文件都放在这里。会被iTunes备份。

tmp/: 保存应用运行时所需要的临时数据。不会被iTunes备份。iPhone重启时，会被清空。

// 获取沙盒根目录路径

NSString *homeDir = NSHomeDirectory();

// 获取Documents目录路径

NSString *docDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES) firstObject];

//获取Library的目录路径

NSString *libDir = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory,NSUserDomainMask,YES) lastObject];

// 获取cache目录路径

NSString *cachesDir = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory,NSUserDomainMask,YES) firstObject];

// 获取tmp目录路径

NSString *tmpDir =NSTemporaryDirectory();

// 获取应用程序程序包中资源文件路径的方法：

NSString *bundle = [[NSBundle mainBundle] bundlePath];

NSLog(@"homeDir=%@ \n docDir=%@ \n libDir=%@ \n cachesDir=%@ \n tmpDir=%@ \n bundle=%@", homeDir,docDir, libDir, cachesDir, tmpDir, bundle);

结果为：

homeDir=/var/mobile/Containers/Data/Application/FBE41071-F5DD-4F02-9DFC-E9E473D3C917

docDir=/var/mobile/Containers/Data/Application/FBE41071-F5DD-4F02-9DFC-E9E473D3C917/Documents

libDir=/var/mobile/Containers/Data/Application/FBE41071-F5DD-4F02-9DFC-E9E473D3C917/Library

cachesDir=/var/mobile/Containers/Data/Application/FBE41071-F5DD-4F02-9DFC-E9E473D3C917/Library/Caches

tmpDir=/private/var/mobile/Containers/Data/Application/FBE41071-F5DD-4F02-9DFC-E9E473D3C917/tmp/

bundle=/var/containers/Bundle/Application/4A42EF08-30BA-4C19-B0C9-62903300C2BC/SandboxDemo.app

关于NSSearchPathForDirectoriesInDomains函数

FOUNDATION_EXPORT NSArray *NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory directory, NSSearchPathDomainMask domainMask, BOOL expandTilde); 用于查找目录，返回指定范围内的指定名称的目录的路径集合。有三个参数：

NSSearchPathDirectory directory 想要查找的目录，是个枚举值，有很多值，有关于iOS的，有关于macOS，也有关于watchOS的。

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

};

NSSearchPathDomainMask domainMask 表示“想要从哪个路径区域保护区查找”。

typedef NS_OPTIONS(NSUInteger, NSSearchPathDomainMask) {

NSUserDomainMask =1, // 用户的主目录

NSLocalDomainMask =2, // 当前机器的本地目录

NSNetworkDomainMask =4, //在网络中公开可用的位置

NSSystemDomainMask =8, // 被苹果系统提供的，不可更改的位置 (/System)

NSAllDomainsMask = 0x0ffff // 上述所有及未来的位置

};

BOOL expandTilde 表示是否用波浪线显示部分目录路径。~在*nix系统表示当前用户的Home目录。列如上面获取cache目录路径如果使用NO，那么结果就是cachesDir=~/Library/Caches