iOS NSFileManager

最新推荐文章于 2022-05-13 17:09:17 发布

原创最新推荐文章于 2022-05-13 17:09:17 发布 · 817 阅读

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本文详细介绍了如何使用Objective-C进行文件存在性检查、目录内文件枚举、递归目录遍历、目录创建与删除，以及文件创建日期的获取等关键操作。

确定文件是否存在

NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
NSString *filePath = [documentsPath stringByAppendingPathComponent:@"file.txt"];
BOOL fileExists = [fileManager fileExistsAtPath:filePath];

列出文件里面的所有目录

NSFileManager *fileManager = [NSFileManager defaultManager];
NSURL *bundleURL = [[NSBundle mainBundle] bundleURL];
NSArray *contents = [fileManager contentsOfDirectoryAtURL:bundleURL
                               includingPropertiesForKeys:@[]
                                                  options:NSDirectoryEnumerationSkipsHiddenFiles
                                                    error:nil];

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"pathExtension == 'png'"];
for (NSURL *fileURL in [contents filteredArrayUsingPredicate:predicate]) {
    // 在目录中枚举 .png 文件
}

在目录中递归地遍历文件

NSFileManager *fileManager = [NSFileManager defaultManager];
NSURL *bundleURL = [[NSBundle mainBundle] bundleURL];
NSDirectoryEnumerator *enumerator = [fileManager enumeratorAtURL:bundleURL
                                      includingPropertiesForKeys:@[NSURLNameKey, NSURLIsDirectoryKey]
                                                         options:NSDirectoryEnumerationSkipsHiddenFiles
                                                    errorHandler:^BOOL(NSURL *url, NSError *error)
{
    if (error) {
        NSLog(@"[Error] %@ (%@)", error, url);
        return NO;
    }

    return YES;
}];

NSMutableArray *mutableFileURLs = [NSMutableArray array];
for (NSURL *fileURL in enumerator) {
    NSString *filename;
    [fileURL getResourceValue:&filename forKey:NSURLNameKey error:nil];

    NSNumber *isDirectory;
    [fileURL getResourceValue:&isDirectory forKey:NSURLIsDirectoryKey error:nil];

    // Skip directories with '_' prefix, for example
    if ([filename hasPrefix:@"_"] && [isDirectory boolValue]) {
        [enumerator skipDescendants];
        continue;
    }

    if (![isDirectory boolValue]) {
        [mutableFileURLs addObject:fileURL];
    }
}

创建一个目录

NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
NSString *imagesPath = [documentsPath stringByAppendingPathComponent:@"images"];
if (![fileManager fileExistsAtPath:imagesPath]) {
    [fileManager createDirectoryAtPath:imagesPath withIntermediateDirectories:NO attributes:nil error:nil];
}］

删除一个目录

NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
NSString *filePath = [documentsPath stringByAppendingPathComponent:@"image.png"];
NSError *error = nil;

if (![fileManager removeItemAtPath:filePath error:&error]) {
    NSLog(@"[Error] %@ (%@)", error, filePath);
}

删除文件的创建日期

NSFileManager *fileManager = [NSFileManager defaultManager];
NSString *documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
NSString *filePath = [documentsPath stringByAppendingPathComponent:@"Document.pages"];

NSDate *creationDate = nil;
if ([fileManager fileExistsAtPath:filePath]) {
    NSDictionary *attributes = [fileManager attributesOfItemAtPath:filePath error:nil];
    creationDate = attributes[NSFileCreationDate];
}