swift – 如何编写NSOutlineView？

Root                      Dictionary    *(1 item)
    Harry Watson          Dictionary    *(5 items)*
        name              String        Harry Watson
        age               Int           99
        birthplace        String        Westminster
        birthdate         Date          01/01/1000
        hobbies           Array         *(2 items)*
            item 0        String        Tennis
            item 1        String        Piano

name            Harry Watson
age             99
birthplace      Westminster
birthdate       01/01/1000
> hobbies       ...             (<- this should be expandable)

func outlineView(_ outlineView: NSOutlineView,viewFor tableColumn: NSTableColumn?,item: Any) -> NSView? {}

我发现Ray Wenderlitch的教程质量差异很大.笑话,冗长,一步一步的手握,假设你对Swift一无所知,这对我来说太令人生厌了.这是一个简短的教程,涵盖了手动和通过Cocoa Bindings填充大纲视图的基础知识.

1.手动填充大纲视图

理解NSOutlineView的关键是必须为每一行提供唯一的标识符,无论是字符串,数字还是表示行的对象. NSOutlineView将其称为项目.基于此项,您将查询数据模型以使用数据填充大纲视图.

Interface Builder安装程序

我们将使用一个非常简单的NSOutlineView,只有两列：Key和Value.

选择第一列并将其标识符更改为keyColumn.然后选择第二列并将其标识符更改为valueColumn：

将单元格的标识符设置为outlineViewCell.你只需要做一次.

码

将以下内容复制并粘贴到ViewController.swift：

// Data model
struct Person {
    var name: String
    var age: Int
    var birthPlace: String
    var birthDate: Date
    var hobbies: [String]
}

class ViewController: NSViewController {
    @IBOutlet weak var outlineView: NSOutlineView!

    // I assume you know how load it from a plist so I will skip
    // that code and use a constant for simplicity
    let person = Person(name: "Harry Watson",age: 99,birthPlace: "Westminster",birthDate: DateComponents(calendar: .current,year: 1985,month: 1,day: 1).date!,hobbies: ["Tennis","Piano"])

    let keys = ["name","age","birthPlace","birthDate","hobbies"]

    override func viewDidLoad() {
        super.viewDidLoad()
        outlineView.dataSource = self
        outlineView.delegate = self
    }
}

extension ViewController: NSOutlineViewDataSource,NSOutlineViewDelegate {

    // You must give each row a unique identifier,referred to as `item` by the outline view
    //   * For top-level rows,we use the values in the `keys` array
    //   * For the hobbies sub-rows,we label them as ("hobbies",0),("hobbies",1),...
    //     The integer is the index in the hobbies array
    //
    // item == nil means it's the "root" row of the outline view,which is not visible
    func outlineView(_ outlineView: NSOutlineView,child index: Int,ofItem item: Any?) -> Any {
        if item == nil {
            return keys[index]
        } else if let item = item as? String,item == "hobbies" {
            return ("hobbies",index)
        } else {
            return 0
        }
    }

    // Tell how many children each row has:
    //    * The root row has 5 children: name,age,birthPlace,birthDate,hobbies
    //    * The hobbies row has how ever many hobbies there are
    //    * The other rows have no children
    func outlineView(_ outlineView: NSOutlineView,numberOfChildrenOfItem item: Any?) -> Int {
        if item == nil {
            return keys.count
        } else if let item = item as? String,item == "hobbies" {
            return person.hobbies.count
        } else {
            return 0
        }
    }

    // Tell whether the row is expandable. The only expandable row is the Hobbies row
    func outlineView(_ outlineView: NSOutlineView,isItemExpandable item: Any) -> Bool {
        if let item = item as? String,item == "hobbies" {
            return true
        } else {
            return false
        }
    }

    // Set the text for each row
    func outlineView(_ outlineView: NSOutlineView,item: Any) -> NSView? {
        guard let columnIdentifier = tableColumn?.identifier.rawValue else {
            return nil
        }

        var text = ""

        // Recall that `item` is the row identiffier
        switch (columnIdentifier,item) {
        case ("keyColumn",let item as String):
            switch item {
            case "name":
                text = "Name"
            case "age":
                text = "Age"
            case "birthPlace":
                text = "Birth Place"
            case "birthDate":
                text = "Birth Date"
            case "hobbies":
                text = "Hobbies"
            default:
                break
            }
        case ("keyColumn",_):
            // Remember that we identified the hobby sub-rows differently
            if let (key,index) = item as? (String,Int),key == "hobbies" {
                text = person.hobbies[index]
            }
        case ("valueColumn",let item as String):
            switch item {
            case "name":
                text = person.name
            case "age":
                text = "(person.age)"
            case "birthPlace":
                text = person.birthPlace
            case "birthDate":
                text = "(person.birthDate)"
            default:
                break
            }
        default:
            text = ""
        }

        let cellIdentifier = NSUserInterfaceItemIdentifier("outlineViewCell")
        let cell = outlineView.makeView(withIdentifier: cellIdentifier,owner: self) as! NSTableCellView
        cell.textField!.stringValue = text

        return cell
    }
}

结果

2.使用Cocoa绑定

填充大纲视图的另一种方法是使用Cocoa Bindings,它可以显着减少您需要编写的代码量.但是,请考虑Cocoa Bindings是一个高级主题.当它工作时,它就像魔术,但如果没有,它可能很难修复. iOS上没有Cocoa Bindings.

码

对于这个例子,让我们通过让NSOutlineView显示多人的详细信息来提高赌注.

// Data Model
struct Person {
    var name: String
    var age: Int
    var birthPlace: String
    var birthDate: Date
    var hobbies: [String]
}

// A wrapper object that represents a row in the Outline View
// Since Cocoa Binding relies on the Objective-C runtime,we need to mark this
// class with @objcMembers for dynamic dispatch
@objcMembers class OutlineViewRow: NSObject {
    var key: String                 // content of the Key column
    var value: Any?                 // content of the Value column
    var children: [OutlineViewRow]  // set to an empty array if the row has no children

    init(key: String,value: Any?,children: [OutlineViewRow]) {
        self.key = key
        self.value = value
        self.children = children
    }

    convenience init(person: Person) {
        let hobbies = person.hobbies.map { OutlineViewRow(key: $0,value: nil,children: []) }
        let children = [
            OutlineViewRow(key: "Age",value: person.age,children: []),OutlineViewRow(key: "Birth Place",value: person.birthPlace,OutlineViewRow(key: "Birth Date",value: person.birthDate,OutlineViewRow(key: "Hobbies",children: hobbies)
        ]
        self.init(key: person.name,children: children)
    }
}

class ViewController: NSViewController {
    let people = [
        Person(name: "Harry Watson","Piano"]),Person(name: "Shelock Holmes",age: 164,birthPlace: "London",year: 1854,hobbies: ["Violin","Chemistry"])
    ]

    @objc lazy var rows = people.map { OutlineViewRow(person: $0) }

    override func viewDidLoad() {
        super.viewDidLoad()
    }
}

Interface Builder设置

在你的故事板中：

>从对象库添加树控制器
>选择树控制器并打开属性检查器(Cmd选项4).设置其子项的儿童关键路径.
>打开Bindings检查器(Cmd Opt 7)并为IB对象设置绑定,如下所示.

| IB Object       | Property           | Bind To         | Controller Key  | Model Key Path    |
|-----------------|--------------------|-----------------|-----------------|-------------------|
| Tree Controller | Controller Content | View Controller |                 | self.rows         |
| Outline View    | Content            | Tree Controller | arrangedObjects |                   |
| Table View Cell | Value              | Table Cell View |                 | objectValue.key   |
| (Key column)    |                    |                 |                 |                   |
| Table View Cell | Value              | Table Cell View |                 | objectValue.value |
| (Value column)  |                    |                 |                 |                   |

(不要将Table View Cell与Table Cell View混淆.糟糕的命名,我知道)

结果

您可以使用DateFormatter在两种方法中输出更好的日期,但这对于这个问题并不重要.