macos - List all window names in Swift

Question

I’m learning Swift. How do I fix the following code to list the window names?

import CoreGraphics

let windows = CGWindowListCopyWindowInfo(CGWindowListOption.optionAll, kCGNullWindowID)
for i in 0..<CFArrayGetCount(windows) {
  if let window = CFArrayGetValueAtIndex(windows, i) {
    print(CFDictionaryGetValue(window, kCGWindowName))
  }
}

The error:

main.swift:6:32: error: cannot convert value of type 'UnsafeRawPointer' to expected argument type 'CFDictionary?'
    print(CFDictionaryGetValue(window, kCGWindowName))
                               ^~~~~~
                                      as! CFDictionary

Answer 1

It becomes easier if you avoid using the Core Foundation types and methods, and bridge the values to native Swift types as early as possible.

Here, CGWindowListCopyWindowInfo() returns an optional CFArray of CFDictionaries, and that can be bridged to the corresponding Swift type [[String : Any]]. Then you can access its values with the usual Swift methods (array enumeration and dictionary subscripting):

if let windowInfo = CGWindowListCopyWindowInfo(.optionAll, kCGNullWindowID) as? [[ String : Any]] {
    for windowDict in windowInfo {
        if let windowName = windowDict[kCGWindowName as String] as? String {
            print(windowName)
        }
    }
}