问题是is_Block在SKNode上不存在。
setValue forUndefinedKey
默认会引发NSUndefinedKeyException。
如果你有一个子类,你可以重载这个函数来做你想做的事情。
请参阅https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/KeyValueCoding/Articles/BasicPrinciples.html以更好地理解关键值编码。
如果你想SKNode有一个名为is_Block的自定义变量,你将不得不为SKNode创建一个扩展,并创建一个属性为你存储这些数据。
import Foundation
import SpriteKit
import ObjectiveC
extension SKNode{
var isBlock: Bool {
get {
var key = "isBlock";
guard let block = objc_getAssociatedObject(self, &key) as? Bool
else{
print("Error");
return false
}
print("Success");
return block
}
set(newValue) {
var key = "isBlock";
print("Setting \(newValue)")
objc_setAssociatedObject(self, &key, newValue , objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN)
}
}
}
测试在操场:
import Foundation
import SpriteKit
import ObjectiveC
extension SKNode{
var isBlock: Bool {
get {
var key = "isBlock";
guard let block = objc_getAssociatedObject(self, &key) as? Bool
else{
print("Error");
return false
}
print("Success");
return block
}
set(newValue) {
var key = "isBlock";
print("Setting \(newValue)")
objc_setAssociatedObject(self, &key, newValue , objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN)
}
}
}
let a = SKNode()
let b = SKNode()
a.isBlock = false
b.isBlock = true
print ("\(a.isBlock), \(b.isBlock)")
b.isBlock = false
a.isBlock = true
print ("\(b.isBlock), \(a.isBlock)")
请告诉我这个问题? –