我需要访问文件夹中的每个文件，包括嵌套文件夹中存在的文件。示例文件夹可能如下所示。
animals/
-k.txt
-d.jpg
cat/
-r.txt
-z.jpg
tiger/
-a.jpg
-p.pdf
dog/
-n.txt
-f.jpg
-p.pdf
假设我想对“动物”中不是文件夹的每个文件运行一个进程。遍历文件夹“animals”及其所有子文件夹以访问每个文件的最佳方法是什么？
谢谢。
【问题讨论】：
标签： macos cocoa directory iteration
也许你可以使用这样的东西：
+(void)openEachFileAt:(NSString*)path
{
NSDirectoryEnumerator* enumerator = [[NSFileManager defaultManager] enumeratorAtPath:path];
for (NSString * file in enumerator)
{
// check if it's a directory
BOOL isDirectory = NO;
NSString* fullPath = [path stringByAppendingPathComponent:file];
[[NSFileManager defaultManager] fileExistsAtPath:fullPath
isDirectory: &isDirectory];
if (!isDirectory)
{
// open your file (fullPath)…
}
else
{
[self openEachFileAt: fullPath];
}
}
}
【讨论】：
使用NSDirectoryEnumerator递归枚举你想要的目录下的文件和目录，并要求它告诉你是文件还是目录。以下内容基于-[NSFileManager enumeratorAtURL:includingPropertiesForKeys:options:errorHandler:] 的文档中列出的示例：
NSFileManager *fileManager = [NSFileManager defaultManager];
NSURL *directoryURL = … // URL pointing to the directory you want to browse
NSArray *keys = [NSArray arrayWithObject:NSURLIsDirectoryKey];
NSDirectoryEnumerator *enumerator = [fileManager
enumeratorAtURL:directoryURL
includingPropertiesForKeys:keys
options:0
errorHandler:^BOOL(NSURL *url, NSError *error) {
// Handle the error.
// Return YES if the enumeration should continue after the error.
return YES;
}];
for (NSURL *url in enumerator) {
NSError *error;
NSNumber *isDirectory = nil;
if (! [url getResourceValue:&isDirectory forKey:NSURLIsDirectoryKey error:&error]) {
// handle error
}
else if (! [isDirectory boolValue]) {
// No error and it’s not a directory; do something with the file
}
}
【讨论】：
这是一个快速版本：
func openEachFile(inDirectory path: String) {
let subs = try! FileManager.default.subpathsOfDirectory(atPath: path)
let totalFiles = subs.count
print(totalFiles)
for sub in subs {
if sub.hasSuffix(".DS_Store") {
//a DS_Store file
}
else if sub.hasSuffix(".xcassets") {
//a xcassets file
}
else if (sub as NSString).substring(to: 4) == ".git" {
//a git file
}
else if sub.hasSuffix(".swift") {
//a swift file
}
else if sub.hasSuffix(".m") {
//a objc file
}
else if sub.hasSuffix(".h") {
//a header file
}
else {
// some other file
}
let fullPath = (path as NSString).appendingPathComponent(sub)
}
}
【讨论】：
这是一个使用 -subpathsOfDirectoryAtPath:rootPath 的解决方案，带有文件 URL 和现代 Objective-C 可空性花里胡哨。
typedef void (^FileEnumerationBlock)(NSURL *_Nonnull fileURL);
@interface NSFileManager (Extensions)
- (void)enumerateWithRootDirectoryURL:(nonnull NSURL *)rootURL
fileHandler:(FileEnumerationBlock _Nonnull)fileHandler
error:(NSError *_Nullable *_Nullable)error;
@end
@implementation NSFileManager (Extensions)
- (void)enumerateWithRootDirectoryURL:(NSURL *)rootURL
fileHandler:(FileEnumerationBlock)fileHandler
error:(NSError **)error {
NSString *rootPath = rootURL.path;
NSAssert(rootPath != nil, @"Invalid root URL %@ (nil path)", rootURL);
NSArray *subs = [[NSFileManager defaultManager] subpathsOfDirectoryAtPath:rootPath
error:error];
if (!subs) {
return;
}
for (NSString *sub in subs) {
fileHandler([rootURL URLByAppendingPathComponent:sub]);
}
}
@end
……在 Swift 中也是如此：
func enumerate(rootDirectoryURL rootURL: NSURL, fileHandler:(URL:NSURL)->Void) throws {
guard let rootPath = rootURL.path else {
preconditionFailure("Invalid root URL: \(rootURL)")
}
let subs = try NSFileManager.defaultManager().subpathsOfDirectoryAtPath(rootPath)
for sub in subs {
fileHandler(URL: rootURL.URLByAppendingPathComponent(sub))
}
}
【讨论】：
这段代码对我有用。
NSMutableString *allHash;
-(NSString*)getIterate:(NSString*)path {
allHash = [NSMutableString stringWithString:@""];
NSDirectoryEnumerator *de= [[NSFileManager defaultManager] enumeratorAtPath:path];
NSString *file;
BOOL isDirectory;
for(file in de)
{
//first check if it's a file
NSString* fullPath = [NSString stringWithFormat:@"%@/%@",path,file];
BOOL fileExistsAtPath = [[NSFileManager defaultManager] fileExistsAtPath:fullPath isDirectory:&isDirectory];
NSLog(@"Check=>%d",fileExistsAtPath);
if (!isDirectory) //its a file
{
//Do with filepath
}
else{ //it's a folder, so recurse
[self enumerateFolder:fullPath];
}
}
return allHash;
}
-(void) enumerateFolder:(NSString*)fileName
{
NSDirectoryEnumerator *de= [[NSFileManager defaultManager] enumeratorAtPath:fileName];
NSString* file;
BOOL isDirectory;
for(file in de)
{
//first check if it's a file
BOOL fileExistsAtPath = [[NSFileManager defaultManager] fileExistsAtPath:file isDirectory:&isDirectory];
if (fileExistsAtPath) {
if (!isDirectory) //its a file
{
//Do with file
}
else{ //it's a folder, so recurse
[self enumerateFolder:file];
}
}
else printf("\nenumeratefolder No file at path %s",[file UTF8String]);
}
}
【讨论】：
在 Swift 中我们可以尝试以下方法。
let docsDir = NSHomeDirectory().appending("/Documents")
let localFileManager = FileManager()
let dirEnum = localFileManager.enumerator(atPath: docsDir)
while let file = dirEnum?.nextObject() as? String {
if file.hasSuffix(".doc") {
print(docsDir.appending("/\(file)"))
}
}
参考 https://developer.apple.com/documentation/foundation/filemanager/1408726-enumerator
【讨论】：