运用runtime可以把一个类方法转成block
importFoundation
importUIKit
classDemo:NSObject{
functest(msg:String){
print(msg)
}
}
let sel =#selector(Demo.test(msg:))
///获取test(msg:)的方法
let method:Method=class_getInstanceMethod(Demo.self,sel)
///获取方法实现体的指针
let oldIMP:IMP=method_getImplementation(method)
//把方法体指针转成具体的block
typealiasOldBlockType =@convention(c) (Demo,Selector,String)->Void
let oldBlock =unsafeBitCast(oldIMP, to:OldBlockType.self)
//调用
oldBlock(Demo(),sel,"调用方法。")
