我遇到了JavaScriptCore的一些奇怪问题。每当我向具有参数的类添加方法时，它似乎不会被导出（或者以奇怪的名称导出）。例如：
import Cocoa
import JavaScriptCore
@objc
public protocol MyObjectExport: JSExport {
var property: Int { get set }
init()
func test() -> String
func doNothing(num: Int)
func squared(num: Int) -> Int
func sum(a:Int, _ b: Int) -> Int
}
@objc
public class MyObject: NSObject, MyObjectExport {
public var property: Int {
get {
return 5
}
set {
print("New value \(newValue)")
}
}
public required override init() {
}
public func test() -> String {
return "Tested"
}
public func doNothing(num: Int) {
}
public func squared(num: Int) -> Int {
return num * num
}
public func sum(a: Int, _ b: Int) -> Int {
return a + b
}
}
class ViewController: NSViewController {
override func viewDidLoad() {
let context = JSContext()!
context.exceptionHandler = { context, exc in
print("Exception \(exc)")
}
context.setObject(MyObject.self, forKeyedSubscript: NSString(string: "MyObject"))
context.evaluateScript("var obj = new MyObject()")
print(context.evaluateScript("obj"))
print(context.evaluateScript("obj.test()"))
print(context.evaluateScript("obj.doNothing(5)"))
print(context.evaluateScript("obj.squared(5)"))
print(context.evaluateScript("obj.sum(5,5)"))
}
}
请注意，这必须在macOS应用中进行测试。 JavaScriptCore在游乐场甚至更奇怪。
当这个运行时，我得到输出
<TestProject.MyObject: 0x608000001180>
Tested
Exception Optional(TypeError: obj.doNothing is not a function. (In 'obj.doNothing(5)', 'obj.doNothing' is undefined))
undefined
Exception Optional(TypeError: obj.squared is not a function. (In 'obj.squared(5)', 'obj.squared' is undefined))
undefined
Exception Optional(TypeError: obj.sum is not a function. (In 'obj.sum(5,5)', 'obj.sum' is undefined))
undefined
如您所见，启动器起作用，方法test也起作用。但是，所有其他带参数的方法似乎都没有导出，或者它们是以我找不到的其他方法名称导出的。
非常感谢任何帮助。
答案 0 :(得分：2)
自Swift 3起，默认情况下第一个参数不再未命名。
您无法像这样从Swift代码中调用doNothing，squared和sum：
doNothing(5)
squared(5)
sum(5,5)
您必须包含参数名称：
doNothing(num: 5)
squared(num: 5)
sum(a: 5,5) //argument name not required for 'b' because it is '_'
这些方法获得Objective-C选择器doNothingWithNum:，squaredWithNum:和sumWithA::。根据{{3}}：
导出带有一个或多个参数的选择器时，JavaScriptCore使用以下转换生成相应的函数名称：
从选择器中删除所有冒号。
冒号后面的任何小写字母都是大写的。
因此doNothing，squared和sum被称为doNothingWithNum()，squaredWithNum()和sumWithA()。您必须更改JavaScript以使用这些名称调用方法：
print(context.evaluateScript("obj.doNothingWithNum(5)"))
print(context.evaluateScript("obj.squaredWithNum(5)"))
print(context.evaluateScript("obj.sumWithA(5,5)"))
或者改变你的课程＆amp;用于删除参数名称的协议定义：
@objc
public protocol MyObjectExport: JSExport {
var property: Int { get set }
init()
func test() -> String
func doNothing(_ num: Int)
func squared(_ num: Int) -> Int
func sum(_ a: Int, _ b: Int) -> Int
}
@objc
public class MyObject: NSObject, MyObjectExport {
public var property: Int {
get {
return 5
}
set {
print("New value \(newValue)")
}
}
public required override init() {
}
public func test() -> String {
return "Tested"
}
public func doNothing(_ num: Int) {
}
public func squared(_ num: Int) -> Int {
return num * num
}
public func sum(_ a: Int, _ b: Int) -> Int {
return a + b
}
}
答案 1 :(得分：0)
///创建一个协议，继承JSExport
@objc protocol MYPJSExport: JSExport {
var sum: Int {get set}
func doNothing()
func squared(_ num: Int) -> Int
func add(_ a: Int, _ b: Int) -> Int
func add(num: Int) -> Int
func add(num1: Int, num2: Int) -> Int
func add(num1: Int, _ num2: Int) -> Int
// func add(_ num1: Int, num2: Int) -> Int //the first external parameter is omitted，JS can't call
}
//注意：@objc不能丢失
@objc class MYPObject: NSObject, MYPJSExport {
var sum: Int = 0 {
willSet{
print("newValue: \(newValue) |CurrentThread: \(Thread.current)")
}
didSet{
print("oldValue: \(oldValue) |CurrentThread: \(Thread.current)")
}
}
func add(_ a: Int, _ b: Int) -> Int {
return a + b
}
func doNothing(){
print("doNothing--")
}
func squared(_ num: Int) -> Int {
return num * num
}
func add(num: Int) -> Int {
return num + 10
}
func add(num1: Int, num2: Int) -> Int {
return num1 + num2
}
func add(num1: Int, _ num2: Int) -> Int {
return num1 * num2
}
// func add(_ num1: Int, num2: Int) -> Int {
// return (num1 + num2) * 2
// }
}
class ViewController: UIViewController {
let obj: MYPObject = MYPObject()
let context:JSContext = JSContext()
override func viewDidLoad() {
super.viewDidLoad()
context.exceptionHandler = { (context, exception) in
guard let exce = exception else { return }
context!.exception = exce
print("JS exception: \(exce)")
}
let block: @convention(block) () -> () = {
print("++++++Begin Log++++++")
let args = JSContext.currentArguments()
for jsVal in args! {
print(jsVal)
}
print("---End Log------")
}
context.setObject(block, forKeyedSubscript: NSString(string: "log"))
context.setObject(obj, forKeyedSubscript: NSString(string: "Swiftobj"))
print(context.evaluateScript("log(Swiftobj.doNothing(5))"))
print(context.evaluateScript("log(Swiftobj.squared(5))"))
print(context.evaluateScript("log(Swiftobj.add(5,5))"))
print(context.evaluateScript("log(Swiftobj.addWithNum(5))"))
print(context.evaluateScript("log(Swiftobj.addWithNum1Num2(10,10))"))
print(context.evaluateScript("log(Swiftobj.addWithNum1(10,10))"))
// print(context.evaluateScript("log(Swiftobj.addWithNum2(10,10))")) // 'Swiftobj.addWithNum2' is undefined
context.evaluateScript("Swiftobj.sum = Swiftobj.add(2,3)")
print(context.evaluateScript("log(Swiftobj.sum)"))
print("obj.sum: \(obj.sum)")
}
}