如何在 Swift 中从 CGWindowListCopyWindowInfo 获取唯一 PID 数组答案

【问题标题】：How to get Array of Unique PIDs from CGWindowListCopyWindowInfo in Swift如何在 Swift 中从 CGWindowListCopyWindowInfo 获取唯一 PID 数组
【发布时间】：2017-06-21 15:44:42
【问题描述】：

我正在尝试将以下 Objective-C 方法转换为 Swift 3。目标是为第 0 层中的所有“屏幕上”窗口元素（桌面元素除外）获取一个唯一进程标识符数组 (kCGWindowOwnerPID)。

我的 Obj-C 方法使用 NSSet 从使用 NSPredicate 过滤的 NSArray 中删除重复的 PID

+ (NSArray*)filteredProcessIndentifiers
{
    pid_t myPid = [[NSProcessInfo processInfo] processIdentifier];

    NSArray *windowList = (id)CGWindowListCopyWindowInfo(kCGWindowListOptionOnScreenOnly
                                 | kCGWindowListExcludeDesktopElements,
                                   kCGNullWindowID);

    NSArray *uniquePidArray = [[NSSet setWithArray:[
                    [(id)windowList filteredArrayUsingPredicate:
                        [NSPredicate predicateWithFormat:@"(kCGWindowLayer == 0 && kCGWindowOwnerPID != %d)", myPid]]
                    valueForKey:@"kCGWindowOwnerPID"]]
                    allObjects];

    if (windowList) {
        CFRelease(windowList);
    }

    return uniquePidArray;
}

这个 Swift 3 示例用于获取过滤后的元素数组（在第 0 层而不是 myPid），但是这个测试包含 all keys, 和重复的 PID：

/// - returns: Array of WindowInfo dictionaries.
func windowListFiltered() throws -> [AnyObject] {
    var windowListArray: CFArray?
    let options = CGWindowListOption(arrayLiteral: CGWindowListOption.excludeDesktopElements, CGWindowListOption.optionOnScreenOnly)
    let filterPredicate = NSPredicate(format: "(kCGWindowLayer == 0 && kCGWindowOwnerPID != %d)", getpid())

    windowListArray = CGWindowListCopyWindowInfo(options, kCGNullWindowID)
    let filtered = (windowListArray as NSArray?)?.filtered(using: filterPredicate)
    return (filtered as [AnyObject]?)!
}

windowListFiltered() 方法结果产生：

[{
    kCGWindowAlpha = 1;
    kCGWindowBounds =     {
        Height = 436;
        Width = 770;
        X = 525;
        Y = 313;
    };
    kCGWindowIsOnscreen = 1;
    kCGWindowLayer = 0;
    kCGWindowMemoryUsage = 1072;
    kCGWindowName = Debug;
    kCGWindowNumber = 213;
    kCGWindowOwnerName = Finder;
    kCGWindowOwnerPID = 453;
    kCGWindowSharingState = 1;
    kCGWindowStoreType = 1;
}, {
    kCGWindowAlpha = 1;
    kCGWindowBounds =     {
        Height = 537;
        Width = 380;
        X = 61;
        Y = 354;
    };
    kCGWindowIsOnscreen = 1;
    kCGWindowLayer = 0;
    kCGWindowMemoryUsage = 1072;
    kCGWindowName = Documents;
    kCGWindowNumber = 3416;
    kCGWindowOwnerName = Finder;
    kCGWindowOwnerPID = 453;
    kCGWindowSharingState = 1;
    kCGWindowStoreType = 1;
}, {
    kCGWindowAlpha = 1;
    kCGWindowBounds =     {
        Height = 22;
        Width = 1414;
        X = 118;
        Y = 28;
    };
    kCGWindowIsOnscreen = 1;
    kCGWindowLayer = 0;
    kCGWindowMemoryUsage = 128208;
    kCGWindowName = "swift3 - Cannot subscript a value of type [[String:Any]] with an index of type 'String' - Swift 3 - Stack Overflow";
    kCGWindowNumber = 7798;
    kCGWindowOwnerName = WindowMizer;
    kCGWindowOwnerPID = 495;
    kCGWindowSharingState = 1;
    kCGWindowStoreType = 2;
}]

我需要的是一个像这样的数组：

[453,495]

我已经能够部分到达那里，但我无法从filtered 数组中提取一组 PID。此尝试迭代一个数组以构建第二个数组，这确实有效，但仍然存在重复的 PID - 我可以消除它，但我正在尝试找到实现原始 Goal 的最佳方法。

func filteredProcessIndentifiers() throws -> [Int] {
    var processIds:[Int] = []
    var windowListArray: CFArray?
    let options = CGWindowListOption(arrayLiteral: CGWindowListOption.excludeDesktopElements, CGWindowListOption.optionOnScreenOnly)
    let filterPredicate = NSPredicate(format: "(kCGWindowLayer == 0 && kCGWindowOwnerPID != %d)", getpid())
    windowListArray = CGWindowListCopyWindowInfo(options, kCGNullWindowID)
    let filtered = (windowListArray as NSArray?)?.filtered(using: filterPredicate) as? [[ String : Any]]

    for dict in filtered! {
        processIds.append((dict["kCGWindowOwnerPID"] as! Int))
    }

    return processIds
}

简单来说，考虑到我有filtered 数组，我尝试返回：

filtered["kCGWindowOwnerPID"]

由于错误而无法编译：“Type 'NSArray?'没有下标成员”

我希望创建一些更简洁的东西，比如漂亮的 Objective-C 示例 :-)。今晚我会再试一次，并专注于使用相当于NSSet 的 Swift3 来消除重复。

任何有关从CGWindowListCopyWindowInfo() 获取唯一进程标识符数组的最佳方法的见解将不胜感激。

【问题讨论】：

标签： objective-c arrays swift3 nspredicate core-foundation

【解决方案1】：

函数filteredProcessIndentifiers里面的for循环改成这样：

for diction in filtered! {
    let test = diction as? Dictionary<String,Any>
    if let item = test{
         print("testa: \(String(describing: item["kCGWindowOwnerPID"]))")
    }
}

谢谢。我已经试图解决这个问题将近两天了，遇到你的问题给了我这个想法，它奏效了！所以谢谢你。

【讨论】：