使用 Crashlytics 错误日志修复我的崩溃

Question

我收到了来自 Crashlytics 的错误日志，内容如下：

Crashed: NSOperationQueue 0x1d003d5a0 (QOS: UNSPECIFIED)
0  (App Name)            0x100710fa4 specialized ViewController.(getHistoricalData(url : String, currency : String) -> ()).(closure #1) (ViewController.swift:1324)
1  (App Name)             0x1007029f8 ViewController.(getHistoricalData(url : String, currency : String) -> ()).(closure #1) (ViewController.swift)
2  (App Name)             0x100712178 partial apply for ViewController.(getHistoricalData(url : String, currency : String) -> ()).(closure #1) (ViewController.swift)
3  (App Name)             0x1006fd448 @callee_owned (@owned Data?, @owned URLResponse?, @owned Error?) -> ()NSData?NSData (ViewController.swift)
4  CFNetwork                      0x181fd1d68 __75-[__NSURLSessionLocal taskForClass:request:uploadFile:bodyData:completion:]_block_invoke + 32
5  CFNetwork                      0x181fea6bc __49-[__NSCFLocalSessionTask _task_onqueue_didFinish]_block_invoke + 152
6  Foundation                     0x18241dba0 __NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 16
7  Foundation                     0x18235d894 -[NSBlockOperation main] + 72
8  Foundation                     0x18234d4c4 -[__NSOperationInternal _start:] + 848
9  libdispatch.dylib              0x1813c6a14 _dispatch_client_callout + 16
10 libdispatch.dylib              0x1814029c4 _dispatch_block_invoke_direct$VARIANT$armv81 + 280
11 libdispatch.dylib              0x1813c6a14 _dispatch_client_callout + 16
12 libdispatch.dylib              0x1814029c4 _dispatch_block_invoke_direct$VARIANT$armv81 + 280
13 libdispatch.dylib              0x181402878 dispatch_block_perform$VARIANT$armv81 + 104
14 Foundation                     0x18241f878 __NSOQSchedule_f + 376
15 libdispatch.dylib              0x1813c6a14 _dispatch_client_callout + 16
16 libdispatch.dylib              0x181403640 _dispatch_continuation_pop$VARIANT$armv81 + 420
17 libdispatch.dylib              0x181401fe8 _dispatch_async_redirect_invoke$VARIANT$armv81 + 596
18 libdispatch.dylib              0x1814082a4 _dispatch_root_queue_drain + 568
19 libdispatch.dylib              0x181408008 _dispatch_worker_thread3 + 112
20 libsystem_pthread.dylib        0x18166f06c _pthread_wqthread + 1268
21 libsystem_pthread.dylib        0x18166eb6c start_wqthread + 4

(App Name) 对应于我的应用名称。据我了解，错误发生在 ViewController.swift 的第 1324 行，在函数 getHistoricalData(url : String, currency : String) 中。 函数如下：

func getHistoricalData(url: String, currency: String){
        var Currenturl = NSURL(string: url)


        if Reachability.isConnectedToNetwork() {

            URLSession.shared.dataTask(with: (Currenturl as URL?)!, completionHandler: {(data, response, error) -> Void in
                let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! NSDictionary
                if let jsonObj = jsonObj  {


                  // do some stuff
                }
            }).resume()

        }
    }

第1324行对应let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! NSDictionary

我已经尝试了几种不同的解开jsonObj 的方法来尝试阻止这次崩溃。最初我有类似 if let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? NSDictionary { 的东西，但同样的问题发生了。

这与我打开包装的方式有关吗？任何想法/指针将不胜感激！

Answer 1

如果错误在let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as! NSDictionary，有两个简单的错误原因：

• NSDictionary 的强制转换因任何原因而失败
• 强制解包 data 失败。

不要使用! 强制解包服务器接收到的数据，它可能为零。请改用以下代码：

guard let data = data, let jsonObj = try? JSONSerialization.jsonObject(with: data, options: .allowFragments) as? NSDictionary else { // Handle error here }