在我的应用程序中,我希望在NSPasteboard中添加一些内容时收到通知。如果我从任何其他程序中复制文本,我希望我的应用程序了解它。
我读到的地方不可能那样做。我应该创建一个计时器并自己检查NSPasteboard的内容。
这是方法吗?或者有任何类型的通知吗?
答案 0 :(得分:11)
是的,您基本上必须轮询粘贴板以查看其内容是否已更改。这不是理想的,但它是可能的。基本上,你有一个计时器,每秒触发一次或两次并检查-[NSPasteboard changeCount]
。如果changeCount
发生更改,则表示粘贴板的内容也已更改(或者至少有新的所有者)。
答案 1 :(得分:4)
根据Dave DeLong提供的答案,我提出了类似的实现,但是在快速中,这是其要点的链接:PasteboardWatcher.swift
相同的代码段:
class PasteboardWatcher : NSObject {
// assigning a pasteboard object
private let pasteboard = NSPasteboard.generalPasteboard()
// to keep track of count of objects currently copied
// also helps in determining if a new object is copied
private var changeCount : Int
// used to perform polling to identify if url with desired kind is copied
private var timer: NSTimer?
// the delegate which will be notified when desired link is copied
var delegate: PasteboardWatcherDelegate?
// the kinds of files for which if url is copied the delegate is notified
private let fileKinds : [String]
/// initializer which should be used to initialize object of this class
/// - Parameter fileKinds: an array containing the desired file kinds
init(fileKinds: [String]) {
// assigning current pasteboard changeCount so that it can be compared later to identify changes
changeCount = pasteboard.changeCount
// assigning passed desired file kinds to respective instance variable
self.fileKinds = fileKinds
super.init()
}
/// starts polling to identify if url with desired kind is copied
/// - Note: uses an NSTimer for polling
func startPolling () {
// setup and start of timer
timer = NSTimer.scheduledTimerWithTimeInterval(2, target: self, selector: Selector("checkForChangesInPasteboard"), userInfo: nil, repeats: true)
}
/// method invoked continuously by timer
/// - Note: To keep this method as private I referred this answer at stackoverflow - [Swift - NSTimer does not invoke a private func as selector](http://stackoverflow.com/a/30947182/217586)
@objc private func checkForChangesInPasteboard() {
// check if there is any new item copied
// also check if kind of copied item is string
if let copiedString = pasteboard.stringForType(NSPasteboardTypeString) where pasteboard.changeCount != changeCount {
// obtain url from copied link if its path extension is one of the desired extensions
if let fileUrl = NSURL(string: copiedString) where self.fileKinds.contains(fileUrl.pathExtension!){
// invoke appropriate method on delegate
self.delegate?.newlyCopiedUrlObtained(copiedUrl: fileUrl)
}
// assign new change count to instance variable for later comparison
changeCount = pasteboard.changeCount
}
}
}
共享代码中的注意:我试图识别用户是否已复制了 文件网址与否,提供的代码可以很容易地修改为其他一般 目的。