如何使用NSFileManager
监视目录
我希望能够在我的应用程序运行时检测到我的文档目录中的文件何时被删除/添加。
发布于 2018-04-06 04:57:40
这是我自己用Swift编写的DirectoryWatcher版本,使用GCD而不是Mach,并且使用闭包而不是委托
import Foundation
@objc public class DirectoryWatcher : NSObject {
override public init() {
super.init()
}
deinit {
stop()
}
public typealias Callback = (_ directoryWatcher: DirectoryWatcher) -> Void
@objc public convenience init(withPath path: String, callback: @escaping Callback) {
self.init()
if !watch(path: path, callback: callback) {
assert(false)
}
}
private var dirFD : Int32 = -1 {
didSet {
if oldValue != -1 {
close(oldValue)
}
}
}
private var dispatchSource : DispatchSourceFileSystemObject?
@objc public func watch(path: String, callback: @escaping Callback) -> Bool {
// Open the directory
dirFD = open(path, O_EVTONLY)
if dirFD < 0 {
return false
}
// Create and configure a DispatchSource to monitor it
let dispatchSource = DispatchSource.makeFileSystemObjectSource(fileDescriptor: dirFD, eventMask: .write, queue: DispatchQueue.main)
dispatchSource.setEventHandler {[unowned self] in
callback(self)
}
dispatchSource.setCancelHandler {[unowned self] in
self.dirFD = -1
}
self.dispatchSource = dispatchSource
// Start monitoring
dispatchSource.resume()
// Success
return true
}
@objc public func stop() {
// Leave if not monitoring
guard let dispatchSource = dispatchSource else {
return
}
// Don't listen to more events
dispatchSource.setEventHandler(handler: nil)
// Cancel the source (this will also close the directory)
dispatchSource.cancel()
self.dispatchSource = nil
}
}
像苹果的DirectoryWatcher示例一样使用它,如下所示:
let directoryWatcher = DirectoryWatcher(withPath: "/path/to/the/folder/you/want/to/monitor/", callback: {
print("the folder changed")
})
销毁对象将停止监视,或者您可以显式停止它
directoryWatcher.stop()
它应该与Objective C兼容,因为它的编写方式(未测试)。使用它将如下所示:
DirectoryWatcher *directoryWatcher = [DirectoryWatcher.alloc initWithPath: @"/path/to/the/folder/you/want/to/monitor/" callback: ^(DirectoryWatcher *directoryWatcher) {
NSLog(@"the folder changed")
}];
停止它是相似的
[directoryWatcher stop];
https://stackoverflow.com/questions/7867991
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