14.0~14.6 文件、文件夹的增删查等，NSCoding
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14.0. Introduction（Files and Folder Management）
iOS 是基于OS X的，而OS X又是基于Unix。应用是不能访问整个目录结构的，他只活在自己的沙盒中，而且别的程序也不能访问你沙盒中得内容。每个应用都有自己的沙盒目录和子目录。当程序安装后，系统将为这个程序创建如下目录
Documents/
This folder is the destination for all user-created content. Content that your app has populated, downloaded, or created should not be stored in this folder.
Library/
保存缓存文件和用户偏好设置等，一般情况下，这个目录本身并不直接包含文件，而是包含一些文件夹，这些文件夹来包含文件。
应用的根目录会包含几个文件夹，解释下：
Library/Caches/
包含一些缓存文件，iOS不会备份这里面的文件，当磁盘空间不够，而且你的程序不在运行时，iOS可能就会删除这里面的文件，所以不要让你的程序太依赖这里面的文件，在需要的时候可能重新创建这里面的文件。如果需要一直用这些文件，那么你该把它放在/tmp目录下
Library/Preferences/
偏好设置，iOS back up
Library/Application Support/
app创建的，不包含用户创建的，必须保存到这下面。iOS back up 。此目录并不是自动创建的，如果没有你需要自己创建。
tmp/
app创建的下载的临时文件。not back up by iOS。如果你的程序需要展示一些图片，你有不想每次都去重新下载，这里将是一个好地方让你保存这些照片。这里不要保存用户创建的文档或文件Make sure that you are not storing any user-created documents or files in this folder.
这些目录的作用你也了解了，下一步是如何找到这些目录--api
14.1. Finding the Paths of the Most Useful Folders on Disk
应该使用iOS SDK找到相应的目录，而不该直接认为他们在哪里
请使用相应的api获取你要的目录，比如Documents目录，不要想当然的认为他的名称就是Documents。
NSFileManager 提供了很多文件和文件夹相关的操作。在你的程序中，最好自己创建一个NSFileManager实例，而不要用defaultManager 方法获得的实例，因为它不是线程安全的。
查找目录使用这个方法URLsForDirectory:inDomains:
-(void)testURLsForDirectory
{
NSFileManager *fileManager = [[NSFileManageralloc] init];
NSArray *urls = [fileManagerURLsForDirectory:NSDocumentDirectory
inDomains:NSUserDomainMask];
if ([urls count] > 0){
NSURL *documentsFolder = urls[0];
NSLog(@"%@", documentsFolder);
} else {
NSLog(@"Could not find the Documents folder.");
}
}
打印：
2014-07-02 15:34:43.198 cookbook7_12[541:a0b] file:///Users/sunward/Library/Application%20Support/iPhone%20Simulator/7.0.3/Applications/A0131001-3A2B-421D-BA36-8667D155F685/Documents/
2014-07-02 15:36:55.597 cookbook7_12[219:907] file://localhost/var/mobile/Applications/19E5F719-0326-4788-B127-E618CC0C6523/Documents/
14.2. Writing to and Reading from Files
保存：writeToFile:atomically:encoding:error:
writeToFile 文件保存到哪里
atomically原子的，如果是YES，那么先保存到临时文件，然后再把临时文件移到目标文件，即先保证了文件内容正确，然后再保存到目标位置。所以如果保存过程中程序崩溃，下次进来可以继续保存
encoding 编码，一般式UTF8
error 有错误产生的话，传出来
-(void)testNSStringReadWrite
{
NSString *filePath = [NSTemporaryDirectory()stringByAppendingPathComponent:@"MyFile.txt"];
if ([self writeText:@"Hello, World!"toPath:filePath]){
NSString *readText = [self readTextFromPath:filePath];
if ([readText length] > 0){
NSLog(@"Text read from disk = %@", readText);
} else {
NSLog(@"Failed to read the text from disk.");
}
} else {
NSLog(@"Failed to write the file.");
}
}
- (BOOL) writeText:(NSString *)paramText toPath:(NSString *)paramPath{
return [paramText writeToFile:paramPath
atomically:YES
encoding:NSUTF8StringEncoding
error:nil];
}
- (NSString *) readTextFromPath:(NSString *)paramPath{
return [[NSString alloc]initWithContentsOfFile:paramPath
encoding:NSUTF8StringEncoding
error:nil];
}
打印：
2014-07-02 16:41:05.648 cookbook7_12[242:907] Text read from disk = Hello, World!
当然了，你也可以用URL来表示文件路径，相应的方法是
writeToURL:atomically:encoding:error:
initWithContentsOfFile: encoding: error:
foundation中其他的一些类也跟NSString一样有相应的保存，读取方法。
NSArray在保存数据时，其只能包含以下类型对象
• NSString
• NSDictionary
• NSArray
• NSData
• NSNumber
• NSDate
如果array中有其他对象，那么在保存时将会失败，因为保存时会先检查下所有对象是不是上面所列的对象。因为如果不是上面所列的对象，OC runtime 将不知道如何来保存这个对象
NSDictionary也有非常相似的接口，所能保存的对象也跟NSArray一样。
好吧，这几个高级类我知道怎么保存读取了，那如果是字符数组呢？
数组可以先用NSData封装起来，然后保存，读取，不是吗
14.3. Creating Folders on Disk
创建文件夹
-(void)testCreateDirectory
{
NSFileManager *fileManager = [[NSFileManageralloc] init];
NSString *tempDir =NSTemporaryDirectory();
NSString *imagesDir = [tempDir stringByAppendingPathComponent:@"images"];
NSError *error = nil;
if ([fileManager createDirectoryAtPath:imagesDir
withIntermediateDirectories:YES
attributes:nil
error:&error]){
NSLog(@"Successfully created the directory.");
} else {
NSLog(@"Failed to create the directory. Error = %@", error);
}
}
打印：
2014-07-02 17:05:38.835 cookbook7_12[265:907] Successfully created the directory.
2014-07-02 17:05:42.889 cookbook7_12[265:907] Successfully created the directory.
2014-07-02 17:05:57.985 cookbook7_12[265:907] Successfully created the directory.
我点了3次，居然3次创建成功，本以为从第2次开始会失败的
createDirectoryAtPath将要被创建的目录
withIntermediateDirectories如果是YES，如果最终目录的父（父父....）目录不存在，则创建
attributes文件夹的一些属性，比如修改时间啊，创建时间啊等等，不过简单处理，传nil就可
error 错误信息
14.4. Enumerating Files and Folders
枚举文件，文件夹
-(void)testContentsOfDirectory{
NSFileManager *fileManager = [[NSFileManageralloc] init];
NSString *bundleDir = [[NSBundle mainBundle] bundlePath];
NSError *error = nil;
NSArray *bundleContents = [fileManager
contentsOfDirectoryAtPath:bundleDir
error:&error];
if ([bundleContents count] > 0 && error == nil){
NSLog(@"Contents of the app bundle = %@", bundleContents);
}
else if ([bundleContents count] == 0 && error == nil){
NSLog(@"Call the police! The app bundle is empty.");
}
else {
NSLog(@"An error happened = %@", error);
}
}
打印：
真机上：
2014-07-02 17:29:52.874 cookbook7_12[281:907] Contents of the app bundle = (
"Base.lproj",
"IMG_0257.PNG",
"Info.plist",
"LaunchImage-568h@2x.png",
"LaunchImage-700-568h@2x.png",
"MySong.mp3",
PkgInfo,
"ResourceRules.plist",
"Sample.m4v",
"_CodeSignature",
"cookbook7_12",
"embedded.mobileprovision",
"en.lproj",
"test.jpeg"
)
模拟器上：
2014-07-02 17:31:00.754 cookbook7_12[715:c07] Contents of the app bundle = (
"Assets.car",
"Base.lproj",
"cookbook7_12",
"en.lproj",
"Info.plist",
"LaunchImage-568h@2x.png",
"LaunchImage-700-568h@2x.png",
"MySong.mp3",
PkgInfo,
"Sample.m4v",
"test.jpeg",
"test_cbr.mp3"
)
不过对于获取到的结果，我们很难知道哪个是文件，哪个是文件夹，为了获得更多的信息，我们换个接口
contentsOfDirec toryAtURL:includingPropertiesForKeys:options:error:.
contentsOfDirectoryAtURL //查询目录
includingPropertiesForKeys //你希望返回哪些属性信息
NSURLIsDirectoryKey//是不是目录
NSURLIsReadableKey //你的应用能否访问这个url
NSURLCreationDateKey //创建时间
NSURLContentAccessDateKey //最后一次访问时间
NSURLContentModificationDateKey //最后修改时间
options //0 或者 NSDirectoryEnumerationSkipsHiddenFiles ，是否跳过隐藏文件
error //返回错误信息
-(void)testContentsOfAppBundle{
NSArray *itemsInAppBundle = [self contentsOfAppBundle];
for (NSURL *item in itemsInAppBundle){
[selfprintURLPropertiesToConsole:item];
}
}
- (NSArray *) contentsOfAppBundle{
NSFileManager *manager = [[NSFileManageralloc] init];
NSURL *bundleDir = [[NSBundle mainBundle] bundleURL];
NSArray *propertiesToGet = @[
NSURLIsDirectoryKey,
NSURLIsReadableKey,
NSURLCreationDateKey,
NSURLContentAccessDateKey,
NSURLContentModificationDateKey
];
NSError *error = nil;
NSArray *result = [manager contentsOfDirectoryAtURL:bundleDir
includingPropertiesForKeys:propertiesToGet
options:0
error:&error];
if (error != nil){
NSLog(@"An error happened = %@", error);
}
return result;
}
- (NSString *) stringValueOfBoolProperty:(NSString *)paramProperty
ofURL:(NSURL *)paramURL{
NSNumber *boolValue = nil;
NSError *error = nil;
[paramURL getResourceValue:&boolValue
forKey:paramProperty
error:&error];
if (error != nil){
NSLog(@"Failed to get property of URL. Error = %@", error);
}
return [boolValue isEqualToNumber:@YES] ?@"Yes" : @"No";
}
- (NSString *) isURLDirectory:(NSURL *)paramURL{
return [selfstringValueOfBoolProperty:NSURLIsDirectoryKeyofURL:paramURL];
}
- (NSString *) isURLReadable:(NSURL *)paramURL{
return [selfstringValueOfBoolProperty:NSURLIsReadableKeyofURL:paramURL];
}
- (NSDate *) dateOfType:(NSString *)paramType inURL:(NSURL *)paramURL{
NSDate *result = nil;
NSError *error = nil;
[paramURL getResourceValue:&result
forKey:paramType
error:&error];
if (error != nil){
NSLog(@"Failed to get property of URL. Error = %@", error);
}
return result;
}
- (void) printURLPropertiesToConsole:(NSURL *)paramURL{
NSLog(@"Item name = %@", [paramURLlastPathComponent]);
NSLog(@"Is a Directory? %@", [selfisURLDirectory:paramURL]);
NSLog(@"Is Readable? %@", [selfisURLReadable:paramURL]);
NSLog(@"Creation Date = %@",[selfdateOfType:NSURLCreationDateKeyinURL:paramURL]);
NSLog(@"Access Date = %@",[selfdateOfType:NSURLContentAccessDateKeyinURL:paramURL]);
NSLog(@"Modification Date = %@",[selfdateOfType:NSURLContentModificationDateKeyinURL:paramURL]);
NSLog(@"-----------------------------------");
}
打印：
2014-07-03 14:47:12.172 cookbook7_12[393:c07] Item name = Assets.car
2014-07-03 14:47:12.174 cookbook7_12[393:c07] Is a Directory? No
2014-07-03 14:47:12.174 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.176 cookbook7_12[393:c07] Creation Date = 2014-06-27 07:39:25 +0000
2014-07-03 14:47:12.176 cookbook7_12[393:c07] Access Date = 2014-06-27 07:39:25 +0000
2014-07-03 14:47:12.177 cookbook7_12[393:c07] Modification Date = 2014-06-27 07:39:25 +0000
2014-07-03 14:47:12.177 cookbook7_12[393:c07] -----------------------------------
2014-07-03 14:47:12.178 cookbook7_12[393:c07] Item name = Base.lproj
2014-07-03 14:47:12.178 cookbook7_12[393:c07] Is a Directory? Yes
2014-07-03 14:47:12.178 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.179 cookbook7_12[393:c07] Creation Date = 2014-06-27 06:46:16 +0000
2014-07-03 14:47:12.179 cookbook7_12[393:c07] Access Date = 2014-07-03 06:47:07 +0000
2014-07-03 14:47:12.180 cookbook7_12[393:c07] Modification Date = 2014-06-27 06:46:16 +0000
2014-07-03 14:47:12.180 cookbook7_12[393:c07] -----------------------------------
2014-07-03 14:47:12.180 cookbook7_12[393:c07] Item name = cookbook7_12
2014-07-03 14:47:12.181 cookbook7_12[393:c07] Is a Directory? No
2014-07-03 14:47:12.182 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.182 cookbook7_12[393:c07] Creation Date = 2014-07-03 06:46:53 +0000
2014-07-03 14:47:12.183 cookbook7_12[393:c07] Access Date = 2014-07-03 06:47:07 +0000
2014-07-03 14:47:12.183 cookbook7_12[393:c07] Modification Date = 2014-07-03 06:46:53 +0000
2014-07-03 14:47:12.184 cookbook7_12[393:c07] -----------------------------------
2014-07-03 14:47:12.184 cookbook7_12[393:c07] Item name = en.lproj
2014-07-03 14:47:12.185 cookbook7_12[393:c07] Is a Directory? Yes
2014-07-03 14:47:12.185 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.186 cookbook7_12[393:c07] Creation Date = 2014-06-27 06:21:08 +0000
2014-07-03 14:47:12.186 cookbook7_12[393:c07] Access Date = 2014-07-03 06:47:07 +0000
2014-07-03 14:47:12.187 cookbook7_12[393:c07] Modification Date = 2014-06-27 06:21:08 +0000
2014-07-03 14:47:12.187 cookbook7_12[393:c07] -----------------------------------
2014-07-03 14:47:12.188 cookbook7_12[393:c07] Item name = Info.plist
2014-07-03 14:47:12.188 cookbook7_12[393:c07] Is a Directory? No
2014-07-03 14:47:12.189 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.189 cookbook7_12[393:c07] Creation Date = 2014-06-27 08:00:03 +0000
2014-07-03 14:47:12.190 cookbook7_12[393:c07] Access Date = 2014-07-03 06:47:07 +0000
2014-07-03 14:47:12.190 cookbook7_12[393:c07] Modification Date = 2014-06-27 08:00:03 +0000
2014-07-03 14:47:12.191 cookbook7_12[393:c07] -----------------------------------
2014-07-03 14:47:12.191 cookbook7_12[393:c07] Item name = LaunchImage-568h@2x.png
2014-07-03 14:47:12.191 cookbook7_12[393:c07] Is a Directory? No
2014-07-03 14:47:12.192 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.192 cookbook7_12[393:c07] Creation Date = 2014-06-27 08:00:02 +0000
2014-07-03 14:47:12.193 cookbook7_12[393:c07] Access Date = 2014-06-27 08:00:02 +0000
2014-07-03 14:47:12.193 cookbook7_12[393:c07] Modification Date = 2014-06-27 08:00:02 +0000
2014-07-03 14:47:12.194 cookbook7_12[393:c07] -----------------------------------
2014-07-03 14:47:12.194 cookbook7_12[393:c07] Item name = LaunchImage-700-568h@2x.png
2014-07-03 14:47:12.195 cookbook7_12[393:c07] Is a Directory? No
2014-07-03 14:47:12.195 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.195 cookbook7_12[393:c07] Creation Date = 2014-06-27 08:00:02 +0000
2014-07-03 14:47:12.196 cookbook7_12[393:c07] Access Date = 2014-06-27 08:00:02 +0000
2014-07-03 14:47:12.196 cookbook7_12[393:c07] Modification Date = 2014-06-27 08:00:02 +0000
2014-07-03 14:47:12.197 cookbook7_12[393:c07] -----------------------------------
2014-07-03 14:47:12.197 cookbook7_12[393:c07] Item name = MySong.mp3
2014-07-03 14:47:12.198 cookbook7_12[393:c07] Is a Directory? No
2014-07-03 14:47:12.198 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.199 cookbook7_12[393:c07] Creation Date = 2014-06-27 06:22:19 +0000
2014-07-03 14:47:12.199 cookbook7_12[393:c07] Access Date = 2014-06-27 06:46:17 +0000
2014-07-03 14:47:12.200 cookbook7_12[393:c07] Modification Date = 2014-06-27 06:22:19 +0000
2014-07-03 14:47:12.200 cookbook7_12[393:c07] -----------------------------------
2014-07-03 14:47:12.200 cookbook7_12[393:c07] Item name = PkgInfo
2014-07-03 14:47:12.201 cookbook7_12[393:c07] Is a Directory? No
2014-07-03 14:47:12.201 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.202 cookbook7_12[393:c07] Creation Date = 2014-06-27 08:00:03 +0000
2014-07-03 14:47:12.202 cookbook7_12[393:c07] Access Date = 2014-06-27 08:00:03 +0000
2014-07-03 14:47:12.203 cookbook7_12[393:c07] Modification Date = 2014-06-27 08:00:03 +0000
2014-07-03 14:47:12.203 cookbook7_12[393:c07] -----------------------------------
2014-07-03 14:47:12.204 cookbook7_12[393:c07] Item name = Sample.m4v
2014-07-03 14:47:12.204 cookbook7_12[393:c07] Is a Directory? No
2014-07-03 14:47:12.205 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.205 cookbook7_12[393:c07] Creation Date = 2014-06-30 03:54:43 +0000
2014-07-03 14:47:12.205 cookbook7_12[393:c07] Access Date = 2014-06-30 03:54:43 +0000
2014-07-03 14:47:12.206 cookbook7_12[393:c07] Modification Date = 2014-06-30 03:54:43 +0000
2014-07-03 14:47:12.206 cookbook7_12[393:c07] -----------------------------------
2014-07-03 14:47:12.207 cookbook7_12[393:c07] Item name = test.jpeg
2014-07-03 14:47:12.207 cookbook7_12[393:c07] Is a Directory? No
2014-07-03 14:47:12.208 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.208 cookbook7_12[393:c07] Creation Date = 2014-07-02 06:09:20 +0000
2014-07-03 14:47:12.209 cookbook7_12[393:c07] Access Date = 2014-07-02 06:09:20 +0000
2014-07-03 14:47:12.209 cookbook7_12[393:c07] Modification Date = 2014-07-02 06:09:20 +0000
2014-07-03 14:47:12.210 cookbook7_12[393:c07] -----------------------------------
2014-07-03 14:47:12.210 cookbook7_12[393:c07] Item name = test_cbr.mp3
2014-07-03 14:47:12.210 cookbook7_12[393:c07] Is a Directory? No
2014-07-03 14:47:12.211 cookbook7_12[393:c07] Is Readable? Yes
2014-07-03 14:47:12.211 cookbook7_12[393:c07] Creation Date = 2014-06-27 06:21:08 +0000
2014-07-03 14:47:12.212 cookbook7_12[393:c07] Access Date = 2014-06-27 06:46:17 +0000
2014-07-03 14:47:12.212 cookbook7_12[393:c07] Modification Date = 2014-06-27 06:21:08 +0000
14.5. Deleting Files and Folders
删除文件，文件夹
-(void)testDeleteFileAndFolder
{
NSString * txtPath = [NSTemporaryDirectory()stringByAppendingPathComponent:@"text"];
NSLog(@"txtPath=%@",txtPath);
self.fileManager = [[NSFileManageralloc] init];
[selfcreateFolder:txtPath];
[selfcreateFilesInFolder:txtPath];
[selfenumerateFilesInFolder:txtPath];
[selfdeleteFilesInFolder:txtPath];
[selfdeleteFolder:txtPath];
}
/* Creates a folder at a given path */
- (void) createFolder:(NSString *)paramPath{
NSError *error = nil;
if ([self.fileManagercreateDirectoryAtPath:paramPath
withIntermediateDirectories:YES
attributes:nil
error:&error] == NO){
NSLog(@"Failed to create folder %@. Error = %@",paramPath,error);
}else{
NSLog(@"succeeded to create folder");
}
}
/* Creates 5 .txt files in the given folder, named 1.txt, 2.txt, etc */
- (void) createFilesInFolder:(NSString *)paramPath{/* Create 10 files */
for (NSUInteger counter = 0; counter < 5; counter++){
NSString *fileName = [NSString stringWithFormat:@"%lu.txt", (unsignedlong)counter+1];
NSString *path = [paramPath stringByAppendingPathComponent:fileName];
NSString *fileContents = [NSString stringWithFormat:@"Some text"];
NSError *error = nil;
if ([fileContents writeToFile:path
atomically:YES
encoding:NSUTF8StringEncoding
error:&error] == NO){
NSLog(@"Failed to save file to %@. Error = %@", path, error);
}else{
NSLog(@"succeed to save file to %@",path);
}
}
}
/* Enumerates all files/folders at a given path */
- (void) enumerateFilesInFolder:(NSString *)paramPath{
NSError *error = nil;
NSArray *contents = [self.fileManagercontentsOfDirectoryAtPath:paramPath
error:&error];
if ([contents count] > 0 && error == nil){
NSLog(@"Contents of path %@ = \n%@", paramPath, contents);
}
else if ([contents count] == 0 && error == nil){
NSLog(@"Contents of path %@ is empty!", paramPath);
}
else {
NSLog(@"Failed to enumerate path %@. Error = %@", paramPath, error);
}
}
/* Deletes all files/folders in a given path */
- (void)deleteFilesInFolder:(NSString *)paramPath{
NSError *error = nil;
NSArray *contents = [self.fileManagercontentsOfDirectoryAtPath:paramPath error:&error];
if (error == nil){
error = nil;
for (NSString *fileName in contents){
/* We have the file name, to delete it,
we have to have the full path */
NSString *filePath = [paramPath stringByAppendingPathComponent:fileName];
if ([self.fileManagerremoveItemAtPath:filePath error:&error] == NO){
NSLog(@"Failed to remove item at path %@. Error = %@",fileName,error);
}else{
NSLog(@"succeed to remove item at path %@",fileName);
}
}
} else {
NSLog(@"Failed to enumerate path %@. Error = %@", paramPath, error);
}
}
/* Deletes a folder with a given path */
- (void) deleteFolder:(NSString *)paramPath{
NSError *error = nil;
if ([self.fileManagerremoveItemAtPath:paramPath error:&error] == NO){
NSLog(@"Failed to remove path %@. Error = %@", paramPath, error);
}else{
NSLog(@"Succeed to remove path %@",paramPath);
}
}
打印：
2014-07-03 15:33:42.771 cookbook7_12[1370:907] txtPath=/private/var/mobile/Applications/19E5F719-0326-4788-B127-E618CC0C6523/tmp/text
2014-07-03 15:33:42.776 cookbook7_12[1370:907] succeeded to create folder
2014-07-03 15:33:42.780 cookbook7_12[1370:907] succeed to save file to /private/var/mobile/Applications/19E5F719-0326-4788-B127-E618CC0C6523/tmp/text/1.txt
2014-07-03 15:33:42.783 cookbook7_12[1370:907] succeed to save file to /private/var/mobile/Applications/19E5F719-0326-4788-B127-E618CC0C6523/tmp/text/2.txt
2014-07-03 15:33:42.788 cookbook7_12[1370:907] succeed to save file to /private/var/mobile/Applications/19E5F719-0326-4788-B127-E618CC0C6523/tmp/text/3.txt
2014-07-03 15:33:42.792 cookbook7_12[1370:907] succeed to save file to /private/var/mobile/Applications/19E5F719-0326-4788-B127-E618CC0C6523/tmp/text/4.txt
2014-07-03 15:33:42.796 cookbook7_12[1370:907] succeed to save file to /private/var/mobile/Applications/19E5F719-0326-4788-B127-E618CC0C6523/tmp/text/5.txt
2014-07-03 15:33:42.799 cookbook7_12[1370:907] Contents of path /private/var/mobile/Applications/19E5F719-0326-4788-B127-E618CC0C6523/tmp/text =
(
"1.txt",
"2.txt",
"3.txt",
"4.txt",
"5.txt"
)
2014-07-03 15:33:42.803 cookbook7_12[1370:907] succeed to remove item at path 1.txt
2014-07-03 15:33:42.806 cookbook7_12[1370:907] succeed to remove item at path 2.txt
2014-07-03 15:33:42.809 cookbook7_12[1370:907] succeed to remove item at path 3.txt
2014-07-03 15:33:42.812 cookbook7_12[1370:907] succeed to remove item at path 4.txt
2014-07-03 15:33:42.814 cookbook7_12[1370:907] succeed to remove item at path 5.txt
2014-07-03 15:33:42.817 cookbook7_12[1370:907] Succeed to remove path /private/var/mobile/Applications/19E5F719-0326-4788-B127-E618CC0C6523/tmp/text
14.6. Saving Objects to Files
保存和读取新增类的对象到磁盘
首先你的类要遵守NSCoding 协议
看看你的类长什么样子，比如这样：
@interface Person :NSObject <NSCoding>
@property (nonatomic,copy) NSString *firstName;
@property (nonatomic,copy) NSString *lastName;
@end
NSString *const kFirstNameKey =@"FirstNameKey";
NSString *const kLastNameKey =@"LastNameKey";
@implementation Person
- (void)encodeWithCoder:(NSCoder *)aCoder{
[aCoder encodeObject:self.firstNameforKey:kFirstNameKey];
[aCoder encodeObject:self.lastNameforKey:kLastNameKey];
}
- (instancetype)initWithCoder:(NSCoder *)aDecoder{
self = [super init];
if (self != nil){
_firstName = [aDecoder decodeObjectForKey:kFirstNameKey];
_lastName = [aDecoder decodeObjectForKey:kLastNameKey];
}
return self;
}
@end
测试一下保存和读取
-(void)testSaveYourClass
{
/* Define the name and the last name we are going to set in the object */
NSString *const kFirstName = @"Steven";
NSString *const kLastName = @"Jobs";
/* Determine where we want to archive the object */
NSString *filePath = [NSTemporaryDirectory()stringByAppendingPathComponent:@"steveJobs.txt"];
/* Instantiate the object */
Person *steveJobs = [[Person alloc] init];
steveJobs.firstName = kFirstName;
steveJobs.lastName = kLastName;
/* Archive the object to the file */
[NSKeyedArchiverarchiveRootObject:steveJobs toFile:filePath];
/* Now unarchive the same class into another object */
Person *cloneOfSteveJobs =[NSKeyedUnarchiverunarchiveObjectWithFile:filePath];
/* Check if the unarchived object has the same first name and last name
as the previously-archived object */
if ([cloneOfSteveJobs.firstName isEqualToString:kFirstName] && [cloneOfSteveJobs.lastNameisEqualToString:kLastName]){
NSLog(@"Unarchiving worked");
} else {
NSLog(@"Could not read the same values back. Oh no!");
}
/* We no longer need the temp file, delete it */
NSFileManager *fileManager = [[NSFileManageralloc] init];
[fileManager removeItemAtPath:filePath error:nil];
}
打印：
2014-07-03 16:41:55.705 cookbook7_12[1408:907] Unarchiving worked
- 14.0~14.6 文件、文件夹的增删查等，NSCoding
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