想了解沙盒？看我就够了！

iOS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，此区域被成为沙盒，所以所有的非代码文件都要保存在此，例如图像，图标，声音，映像，属性列表，文本文件等。

沙盒文件的目录结构:

• Documents

• Library

  • Caches

  • Preferences

• tmp

沙盒下各文件夹保存内容的区别

• Documents：保存应用运行时生成的需要持久化的数据，iTunes同步设备时会备份该目录。例如，游戏应用可以将游戏存档保存在该目录下。如果用户将缓存存放在这个文件夹下，会导致应用审核无法通过。
• tmp：保存应用运行时所需要的临时数据,使用完毕后再将相应的文件从该目录删除。应用没有运行时，系统也可能会清除该目录下的文件。iTunes同步设备时不会备份该目录。
• Library/Caches：保存应用运行时生成的需要持久化的数据，iTunes同步设备时不会备份该目录。一般存储体积大，不需要备份的非重要数据。
• Library/Preference：保存应用的所有偏好设置，iOS的Settings(设置)应用会在该目录中查找应用的设置信息。iTunes同步设备时会备份该目录。

获取程序的Home目录

NSString *homeDirectory = NSHomeDirectory();
NSLog(@"path:%@", homeDirectory);

获取document目录

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *path = [paths objectAtIndex:0];

获取Cache目录

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *path = [paths objectAtIndex:0];

获取Library目录

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES);
NSString *path = [paths objectAtIndex:0];

获取Tmp目录

NSString *tmpDir = NSTemporaryDirectory();
NSLog(@"%@", tmpDir);

创建文件夹

-(void)createDirectory{
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *iOSDirectory = [documentsPath stringByAppendingPathComponent:@"/iOS"];
    BOOL isSuccess = [fileManager createDirectoryAtPath:iOSDirectory withIntermediateDirectories:YES attributes:nil error:nil];
    if (isSuccess) {
        NSLog(@"success");
    } else {
        NSLog(@"fail");
    }
}

创建文件

-(void)createFile{
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *iOSPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    BOOL isSuccess = [fileManager createFileAtPath:iOSPath contents:nil attributes:nil];
    if (isSuccess) {
        NSLog(@"success");
    } else {
        NSLog(@"fail");
    }
}

写文件

-(void)writeFile{
    NSString *documentsPath =[self getDocumentsPath];
    NSString *iOSPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *content = @"我要写数据啦";
    BOOL isSuccess = [content writeToFile:iOSPath atomically:YES encoding:NSUTF8StringEncoding error:nil];
    if (isSuccess) {
        NSLog(@"write success");
    } else {
        NSLog(@"write fail");
    }
}

NSString * fileName = @"testFileNSFileManager.txt";
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
//获取文件路径
NSString *path = [documentsDirectory stringByAppendingPathComponent:fileName];
//待写入的数据
NSString *temp = @"nihao 世界";
int dataInt = 1234;
float dataFloat = 3.14f;
//创建数据缓冲
NSMutableData *writer = [[NSMutableData alloc] init];
//将字符串添加到缓冲中
[writer appendData:[temp dataUsingEncoding:NSUTF8StringEncoding]];
//将其他数据添加到缓冲中
[writer appendBytes:&dataInt length:sizeof(dataInt)];
[writer appendBytes:&dataFloat length:sizeof(dataFloat)];
//将缓冲的数据写入到文件中
[writer writeToFile:path atomically:YES];

读取文件内容

-(void)readFileContent{
    NSString *documentsPath =[self getDocumentsPath];
    NSString *iOSPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *content = [NSString stringWithContentsOfFile:iOSPath encoding:NSUTF8StringEncoding error:nil];
    NSLog(@"read success: %@",content);
}

//读取数据：
int intData;
float floatData = 0.0;
NSString *stringData;

NSData *reader = [NSData dataWithContentsOfFile:path];
stringData = [[NSString alloc] initWithData:[reader subdataWithRange:NSMakeRange(0, [temp length])]
                                   encoding:NSUTF8StringEncoding];
[reader getBytes:&intData range:NSMakeRange([temp length], sizeof(intData))];
[reader getBytes:&floatData range:NSMakeRange([temp length] + sizeof(intData), sizeof(floatData))];
NSLog(@"stringData:%@ intData:%d floatData:%f", stringData, intData, floatData);

判断文件是否存在

- (BOOL)isSxistAtPath:(NSString *)filePath{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL isExist = [fileManager fileExistsAtPath:filePath];
    return isExist;
}

计算文件大小

- (unsigned long long)fileSizeAtPath:(NSString *)filePath{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL isExist = [fileManager fileExistsAtPath:filePath];
    if (isExist){
        unsigned long long fileSize = [[fileManager attributesOfItemAtPath:filePath error:nil] fileSize];
        return fileSize;
    } else {
        NSLog(@"file is not exist");
        return 0;
    }
}

计算整个文件夹中所有文件大小

- (unsigned long long)folderSizeAtPath:(NSString*)folderPath{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL isExist = [fileManager fileExistsAtPath:folderPath];
    if (isExist){
        NSEnumerator *childFileEnumerator = [[fileManager subpathsAtPath:folderPath] objectEnumerator];
        unsigned long long folderSize = 0;
        NSString *fileName = @"";
        while ((fileName = [childFileEnumerator nextObject]) != nil){
            NSString* fileAbsolutePath = [folderPath stringByAppendingPathComponent:fileName];
            folderSize += [self fileSizeAtPath:fileAbsolutePath];
        }
        return folderSize / (1024.0 * 1024.0);
    } else {
        NSLog(@"file is not exist");
        return 0;
    }
}

删除文件

-(void)deleteFile{
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *iOSPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    BOOL isSuccess = [fileManager removeItemAtPath:iOSPath error:nil];
    if (isSuccess) {
        NSLog(@"delete success");
    }else{
        NSLog(@"delete fail");
    }
}

移动文件

- (void)moveFileName
{
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *filePath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *moveToPath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    BOOL isSuccess = [fileManager moveItemAtPath:filePath toPath:moveToPath error:nil];
    if (isSuccess) {
        NSLog(@"rename success");
    }else{
        NSLog(@"rename fail");
    }
}

重命名

- (void)renameFileName
{
    //通过移动该文件对文件重命名
    NSString *documentsPath =[self getDocumentsPath];
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSString *filePath = [documentsPath stringByAppendingPathComponent:@"iOS.txt"];
    NSString *moveToPath = [documentsPath stringByAppendingPathComponent:@"rename.txt"];
    BOOL isSuccess = [fileManager moveItemAtPath:filePath toPath:moveToPath error:nil];
    if (isSuccess) {
        NSLog(@"rename success");
    }else{
        NSLog(@"rename fail");
    }
}