参考github的 V2ex
在此进行了简化，适合萌新学习，包括我自己
import UIKit
import KVOController //oc的框架
class TTTViewController: UIViewController {
@IBOutlet weak var lb: UILabel!
@IBAction func Largeaction(_ sender: Any) {
model.setFontSize(size: Model.modelLarge)
}
@IBAction func MAction(_ sender: Any) {
model.setFontSize(size: Model.modelMiddle)
}
@IBAction func sAction(_ sender: Any) {
model.setFontSize(size: Model.modelSmall)
}
let model = Model.sharedInstance;
override func viewDidLoad() {
super.viewDidLoad()
///每个要改字体的页面要有这个block
self.fontChangedHandler = { font in
print("TTT字体大小改变:\(font) ---------------- 5")
self.lb.font = UIFont.systemFont(ofSize: CGFloat(font));
}
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
self.dismiss(animated: true, completion: nil)
}
}
import UIKit
protocol FontSizrProtocol {
var sizeLarge:CGFloat {get}
var sizeMiddle:CGFloat{get}
var sizeSmall:CGFloat{get}
}
class Model: NSObject,FontSizrProtocol {
static let sharedInstance = Model()
override init() {
FontSize = "Middle";
super.init();
}
static let modelLarge = "Large"
static let modelMiddle = "Middle"
static let modelSmall = "Small"
@objc dynamic var FontSize:String
var font = 17;
var sizeLarge: CGFloat{
return 30;
}
var sizeMiddle: CGFloat{
return 20;
}
var sizeSmall: CGFloat{
return 10
}
func setFontSize(size:String) {
if FontSize == size {
return
}
if size == "Large"{
font = 30;
}
if size == "Middle"{
font = 20
}
if size == "Small" {
font = 10
}
self.FontSize = size;
}
}
extension NSObject {
fileprivate struct AssociatedKeys {
static var thmemChanged = "thmemChanged"
static var fontChanged = "fontChanged"
}
public typealias FontChangedClosure = @convention(block) (_ fontSize:Float) ->Void
var fontChangedHandler:FontChangedClosure?{
get{
print("-------------- get now ---------- 4 ")
let closureObject: AnyObject? = objc_getAssociatedObject(self, &AssociatedKeys.fontChanged) as AnyObject?
guard closureObject != nil else{
return nil
}
let closure = unsafeBitCast(closureObject, to: FontChangedClosure.self)
return closure }
set{
print("------------ set now ----------- 2 ")
guard let value = newValue else{
return
}
let dealObject: AnyObject = unsafeBitCast(value, to: AnyObject.self)
objc_setAssociatedObject(self, &AssociatedKeys.fontChanged,dealObject,objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
self.kvoController.observe(Model.sharedInstance, keyPath: "FontSize", options: [.initial,.new] , block: {[weak self] (nav, color, change) -> Void in
print("--------监听到了------ 3")
self?.fontChangedHandler?(Float(Model.sharedInstance.font))
}
)
}
}
}
