如何將任何轉換爲​​Swift 3中的CGFloat

Question

我需要任何CGFloat。

但是，我得到了一個致命的錯誤。 爲什麼不能將任何指定給CGFloat？如何轉換？

let lx = ix as! CGFloat 

錯誤消息：

線程1：EXC_BAD_INSTRUCTION（代碼= EXC_l386_INVOP，子碼=爲0x0）

0x1040dcbf1 < 1329>：MOVSD -0xc0（％RBP），％XMM0; XMM0 = MEM [0]，零

打印日誌：

CGFloat的：-0.5

CGFloat的：-0.5

代碼：

import Foundation 
    import UIKit 

// creation of blocks 
class Block { 
    var blockRect = [Rectangle]() 
    var type : String = String() 
    var w : Int = Int() 
    var h : Int = Int() 
    var start_x = CGFloat() 
    var start_y = CGFloat() 
    var start_w_offset : Int? = Int() 
    var blockView = UIView() 

    func unwrap<T>(_ any: T) -> Any 
    { 
     let mirror = Mirror(reflecting: any) 
     guard mirror.displayStyle == .optional, let first = mirror.children.first else { 
      return any 
     } 
     return first.value 
    } 

    init(map : [NSDictionary], color : UIColor, view : UIView, block_view : UIView, x: CGFloat, w: Int, h: Int, type: String, start_w_offset: Int?) { 
     self.blockView = block_view 
     for i in map { 

      let ix = unwrap(i["x"]) 
      let iy = unwrap(i["y"]) 

      print("CGFloat: \(ix)") 
      print("CGFloat: \(iy)") 

      let lx = ix as! CGFloat 
      let ly = iy as! CGFloat 
      let rd_x = x + lx * (size + padding) 
      let rd_y = 450 + ly * (size + padding) 
      let inner_x = block_view.frame.width/2 + lx * (size + padding) 
      let inner_y = block_view.frame.height/2 + ly * (size + padding) 
      self.start_x = x 
      self.start_y = 0 

      let r = Rectangle(type: "special", x: inner_x, y: inner_y, size: size, color: color, view: view, real_x : rd_x, real_y : rd_y) 
      self.blockRect.append(r) 
      self.type = type 
      self.w = w 
      self.start_w_offset = start_w_offset 
      self.h = h 
     } 
    } 
} 

Answer 1

可能是ix和iy只是Double，但不是CGFloat，首先嚐試將其轉換爲Double，然後您可以輕鬆地將Double轉換爲CGFloat。

let lx = CGFloat(ix as? Double ?? 0) 
let ly = CGFloat(iy as? Double ?? 0)