【Swift Mac開發】純代碼創建NSViewController

　　對於習慣了純代碼iOS開發的人來說，剛接觸Mac端開發時，是非常不友好的，網上所有的教程都是通過Xib或StoryBoard的方式創建NSViewController，而且蘋果文檔也是鼓勵用Xib的開發進行Mac 開發，但對於純代碼開發也給了補救方式，現在給大家分享一種可以直接代碼創建的方式。

　　Apple Document:

If you pass in a nil for nibNameOrNil then nibName will return nil and loadView will throw an exception; in this case you must invoke setView: before view is invoked, or override loadView.

　　翻譯如下：

如果爲nbNameOrNil傳遞nil，則nibName將返回nil，並且loadView會引發異常；在這種情況下，您必須在調用視圖之前調用setView：，或重寫loadView。

　　如果不補救，對於通過JFProgrammaticallyViewController()創建的控制器，會報如下錯誤：

 -[NSNib _initWithNibNamed:bundle:options:] could not load the nibName: CodeCreateUiDemo.JFProgrammaticallyViewController in bundle (null).

　　廢話少說，上代碼：

import Cocoa
import SnapKit

class ViewController: NSViewController {

    var button : NSButton!
    override func viewDidLoad() {
        super.viewDidLoad()

        button = NSButton(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
        button.wantsLayer = true
        button.layer?.backgroundColor = NSColor.red.cgColor
        button.title = "click"
        button.target = self
        button.action = #selector(clickAction(sender:))
        self.view.addSubview(button)
    }

    @objc func clickAction(sender:NSButton) {
        let programmaticallyVC = JFProgrammaticallyViewController()
        self.presentAsModalWindow(programmaticallyVC)
    }
    
    override var representedObject: Any? {
        didSet {
        // Update the view, if already loaded.
        }
    }

}





//純代碼創建的ViewController
import Cocoa

class JFProgrammaticallyViewController: NSViewController {

    var mView : NSView!
    
    //這一端是重重之中，對於無法通過Nib加載view，就要通過loadView()方法來進行補救，
    override func loadView() {
        self.view = NSView(frame: CGRect(x: 0, y: 0, width: 400, height: 300))
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        mView = NSView(frame: NSRect(x: 0, y: 0, width: self.view.bounds.size.width, height: self.view.bounds.size.height))
        mView.wantsLayer = true
        mView.layer?.backgroundColor = NSColor.red.cgColor
        self.view.addSubview(mView)
    }
    
}

 　　運行如下圖；