ios - Float 到 Int 转换时崩溃

Question

我的实时应用程序在 Float 到 Int 转换线上随机崩溃。

我无法弄清楚为什么它会崩溃并且无法重现它，因为它是实时应用程序上的随机崩溃。关于如何修复崩溃有什么建议吗？

崩溃日志

Crashed: com.apple.main-thread
0  MyApp                0x100703778 closure #1 in MyViewController.getBalance(isRefreshed:) + 797 (MyViewController.swift:797)
1  MyApp                0x1005c7670 closure #1 in closure #1 in fetchtBalance(completed:) + 185 (Utils.swift:185)
2  MyApp                0x10051ab10 thunk for @escaping @callee_guaranteed () -> () + 4335790864 (<compiler-generated>:4335790864)
3  libdispatch.dylib              0x1ae908b7c _dispatch_call_block_and_release + 32
4  libdispatch.dylib              0x1ae909fd8 _dispatch_client_callout + 20
5  libdispatch.dylib              0x1ae915cc8 _dispatch_main_queue_callback_4CF + 968
6  CoreFoundation                 0x1aebdee0c __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 16
7  CoreFoundation                 0x1aebd9b68 __CFRunLoopRun + 1980
8  CoreFoundation                 0x1aebd9084 CFRunLoopRunSpecific + 480
9  GraphicsServices               0x1b8e27534 GSEventRunModal + 108
10 UIKitCore                      0x1b2d49670 UIApplicationMain + 1940
11 MyApp                0x1004ec6b8 main + 20 (ClientMyProfileViewController.swift:20)
12 libdyld.dylib                  0x1aea58e18 start + 4

代码

import UIKit

var balance: String!
var cost: String?

func getBalance () {
    fetchBalance() { (result, error) in
        guard let balanceFloatValue = Float(balance!) else {
            print("Error")
            return
        }

        guard let costFloat = Float(cost!) else {
            print("Error")
            return
        }

        let costPerSec = costFloat / 60

        let talkTime = balanceFloatValue / costPerSec

        let talkTimeInt = Int(talkTime) // Line No. 797  Crash here

        // ....
    }
}

Answer 1

导致此错误的最可能原因是值本身

let a:Float = 9999999999999999999999.9
let b = "0.000000000000000000001"
let c:Float = a/Float(b)!
let x = Int(c)  // <- Crash here

0/0 会让你崩溃:让 c:Float = a/Float(b)!所以不是这样，但是任何其他可以使 talkTime 在 Int 之外的东西都会让你崩溃 这也可以解释为什么您只会随机遇到错误，因为它仅适用于使该除法为 NaN 或 inf 或 int 之外的值，如 bg2b 所说