所以,我正在尝试开发一个用 Swift 编写的简单游戏,但我在做一件非常简单的事情时遇到了困难。我无法创建随机 CGPoint... 使用 arc4random 时,会出现编译器错误,告诉我无法在 CGPoint 中使用 Int32。那么,有什么办法可以做到这一点吗?有什么解决办法吗?谢谢!
最佳答案
还可以利用 Swift 的基类型扩展来创建一组可重用的 CGPoint 重载函数。也许是这样的:
extension CGPoint {
func random()->CGPoint { return CGPoint(x:Int(arc4random()%1000),y:Int(arc4random()%1000))}
func random(range:Int)->CGPoint {
return CGPoint(x:Int(arc4random()%range),y:Int(arc4random()%range))}
func random(rangeX:Int, rangeY:Int)->CGPoint {
return CGPoint(x:Int(arc4random()%rangeX),y:Int(arc4random()%rangeY))}
}
然后您可以像这样编写随机 CGPoint:
var p = CGPoint.random()
//random x and y with a range of 1000
或
var p = CGPoint.random(range:100)
//random x and y with a range of 100
或
var p = CGPoint.random(rangeX:200, rangeY:400)
//random x up to 200 and random y with a range of up to 400
当然,我现在不在 Xcode IDE 中检查语法/是否正确编译,但希望这能有所帮助:-)
...
///////////////////
Swift 1.2 更新
///////////////////
似乎这些类型级函数调用不再允许扩展......至少对于 CGPoint 来说;可能是因为 CGPoint 实际上是一个结构体,而不是基于当前 IOS 文档的类。
这是我的扩展的更深入版本,它允许范围类型。
这已被确认在 XCode 6.4 Beta 中有效
(此处包含 Playground 文件的 Github 存储库:
https://github.com/princetrunks/Random-CGPoint-Extension )
//creates random CGPoints in Swift as of XCode Beta 6.4 (6E7)
extension CGPoint {
/*private functions that help alleviate the ambiguity of the modulo bias
and nested typecasting as well as recycle similar functionality
for either Int or Range type parameter inputs */
private func randomInt(num:Int) ->Int{
return Int(arc4random_uniform(UInt32(num)))
}
private func randomIntFromRange(numRange:Range<Int>) ->Int{
return Int(arc4random_uniform(UInt32((numRange.endIndex - numRange.startIndex) + numRange.startIndex)))
}
//private variable for the default range
private var defaultRange : Int{
get{return 1000}
}
//(a) public variable that creates a default random CGPoint
static var randomPoint = CGPoint.zeroPoint.random()
//(b) default random point creation
func random()->CGPoint { return CGPoint(x:randomInt(defaultRange),y:randomInt(defaultRange))}
//(c) using an Int parameter for both the random x and y range
func random(range:Int)->CGPoint {
return CGPoint(x:randomInt(range),y:randomInt(range))
}
//(d) allows for the specification of the x and y random range
func random(#rangeX:Int, rangeY:Int)->CGPoint {
return CGPoint(x:randomInt(rangeX),y:randomInt(rangeY))
}
//(e) allows the same functionality as (c) but with a Range<Int> type parameter
func random(range:Range<Int>)->CGPoint {
return CGPoint(x:randomIntFromRange(range), y:randomIntFromRange(range))
}
//(f) allows the same functionality as (d) but with a Range<Int> type parameter
func random(#rangeX:Range<Int>, rangeY:Range<Int> )->CGPoint {
return CGPoint(x:randomIntFromRange(rangeX), y:randomIntFromRange(rangeY))
}
}
以下是我们测试此扩展的方法:
//(a)
let r = CGPoint.randomPoint
//(b)
var anotherRandomPoint = r.random()
//(c)
anotherRandomPoint = r.random(1000)
//(d)
anotherRandomPoint = r.random(0...1000)
//(e)
anotherRandomPoint = r.random(rangeX:90, rangeY: 2000)
//(f)
anotherRandomPoint = r.random(rangeX:0...90, rangeY: 0...2000)
// generates 100 random CGPoints between -1000 and 999
for _ in 0...100 {
anotherRandomPoint.random(-1000...1000)
}
关于swift - 使用 Swift 创建随机 CGPoint,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/24438495/