如何使用NSFileManager
监控目录?
我希望我的应用程序在运行时能够检测到文档目录中的文件何时被删除/添加。
如何使用NSFileManager
监控目录?
我希望我的应用程序在运行时能够检测到文档目录中的文件何时被删除/添加。
这是我自己用Swift编写的DirectoryWatcher版本,使用GCD而不是Mach,并使用闭包代替委托。
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
}
}
使用它类似于苹果的DirectoryWatcher示例,像这样:
let directoryWatcher = DirectoryWatcher(withPath: "/path/to/the/folder/you/want/to/monitor/", callback: {
print("the folder changed")
})
销毁该对象将停止监视,或者您可以明确地停止它。
directoryWatcher.stop()
它应该与Objective C兼容,就像它写的那样(未经测试)。使用它将是这样的:
DirectoryWatcher *directoryWatcher = [DirectoryWatcher.alloc initWithPath: @"/path/to/the/folder/you/want/to/monitor/" callback: ^(DirectoryWatcher *directoryWatcher) {
NSLog(@"the folder changed")
}];
停止它类似
[directoryWatcher stop];