检测到 NSTextView 缺少约束

Question

我创建了一个基于文档的应用程序，它应该将带有图像的 NSAttributedString 保存到包中。我运行应用程序并将图像添加到文本视图并保存。当我打开文件时，一个对话框说“无法打开文档'x'”，并打印到控制台：

[Layout] Detected missing constraints for <NSTextField: 0x100b3f480>.  It cannot be placed because there are not enough constraints to fully 
define the size and origin. Add the missing constraints, or set 
translatesAutoresizingMaskIntoConstraints=YES and constraints will be generated for you. If this view is laid out manually on macOS 10.12 and later, 
you may choose to not call [super layout] from your override. Set a breakpoint on DETECTED_MISSING_CONSTRAINTS to debug. This error will only be logged once.

文档.swift：

enum CookRecipesFileNames : String {

    case notes = "Notes.rtfd"
}

class Document: NSDocument {

    var documentFileWrapper = FileWrapper(directoryWithFileWrappers: [:])

    var popover : NSPopover?

    var notes : NSAttributedString = NSAttributedString()

    ...

    override class func autosavesInPlace() -> Bool {
        return true
    }

    override func fileWrapper(ofType typeName: String) throws -> FileWrapper {

        let notesRTFdata = try self.notes.data(from: NSRange(0..<self.notes.length), documentAttributes: [NSDocumentTypeDocumentAttribute: NSRTFDTextDocumentType])

        if let oldTextFileWrapper = self.documentFileWrapper.fileWrappers?[CookRecipesFileNames.notes.rawValue] {
            self.documentFileWrapper.removeFileWrapper(oldTextFileWrapper)
        }

        self.documentFileWrapper.addRegularFile(withContents: notesRTFdata, preferredFilename: CookRecipesFileNames.notes.rawValue)

        return self.documentFileWrapper
    }

    override func read(from fileWrapper: FileWrapper, ofType typeName: String) throws {
        guard let documentNotesData = fileWrappers[CookRecipesFileNames.notes.rawValue]?.regularFileContents else {
            throw err(.cannotLoadNotes)
        }

        guard let documentNotes = NSAttributedString(rtfd: documentNotesData, documentAttributes: nil) else {
            throw err(.cannotLoadNotes)
        }

        self.documentFileWrapper = fileWrapper

        self.notes = documentNotes
    }

}

任何帮助将不胜感激！

Answer 1

警告“检测到缺少约束...”是构建警告，告诉您已向视图添加约束，但不足以确定视图的 x 和 y 坐标以及高度和宽度。如果您在 IB 中未添加任何约束（此处的一个选项是全部删除），Xcode 将告诉应用程序使用 IB 中使用的确切位置和尺寸。如果向视图添加任何约束，则必须添加足够的约束来确定坐标和两个维度。如果您想保留约束（这是第二个选项），请转到 IB，并在左上角查找黄色或红色警告错误：

这将为您提供视图控制器中缺失和冲突的约束列表。