UI API called on a background thread - iOS 11 - Xcode 9

[ziadtamim]

Hi!

Erik unfortunately does not work on iOS 11. With the new Main Thread Checker in XCode 9 it prints out the following in the console:

• Main Thread Checker: UI API called on a background thread: -[WKWebView navigationDelegate]
• Main Thread Checker: UI API called on a background thread: -[WKWebView evaluateJavaScript:completionHandler:]

Best regards,
Ziad

[phimage]

on your instance of Erik, maybe the shared one you can change the queue

if let engine = Erik.sharedInstance.layoutEngine as? WebKitLayoutEngine {
    engine.javaScriptQueue = .main
    //engine.callBackQueue = .main // maybe this one also if you access some attribute in callback like title
}

I will remove the assert on navigationDelegate

[phimage]

thanks for the PR #29

[stephenfung98]

  let engine = Erik.sharedInstance.layoutEngine as? WebKitLayoutEngine
        engine?.javaScriptQueue = .main
        let url = URL(string: "https://www.ups.com/track?loc=en_US&tracknum=1ZA289R6YW99070191&requester=WT/trackdetails")
        
        engine?.browse(url: url!) { object, error in
            if let e = error {
                
            } else if let doc = object {
                // HTML Inspection
                print(doc)
            }
        }

is still giving me the warning

Main Thread Checker: UI API called on a background thread: -[WKWebView navigationDelegate]

[MainasuK]

2019-03-11 15:30:33.955446+0800 App[81937:34098633] [reports] Main Thread Checker: UI API called on a background thread: -[WKWebView navigationDelegate]
PID: 81937, TID: 34098633, Thread name: (none), Queue name: ErikLoading, QoS: 0
Backtrace:
4   Erik                                0x0000000107f078c6 $S4Erik18WebKitLayoutEngineC16PageLoadedPolicyO17continueConditionySbACcvgSbACcfU1_ + 422
5   Erik                                0x0000000107f0c982 $S4Erik18WebKitLayoutEngineC27handleLoadRequestCompletion33_71293D9CF0077E78ADF7737E6959095DLL17completionHandleryys5Error_pSgXE_tF + 178
6   Erik                                0x0000000107f0c38d $S4Erik18WebKitLayoutEngineC14currentContent17completionHandleryyypSg_s5Error_pSgtcSg_tFyycfU_ + 173
7   Erik                                0x0000000107f10e95 $S4Erik18WebKitLayoutEngineC14currentContent17completionHandleryyypSg_s5Error_pSgtcSg_tFyycfU_TA + 21
8   Erik                                0x0000000107f0cb4d $SIeg_IeyB_TR + 45
9   libdispatch.dylib                   0x000000010c96a595 _dispatch_call_block_and_release + 12
10  libdispatch.dylib                   0x000000010c96b602 _dispatch_client_callout + 8
11  libdispatch.dylib                   0x000000010c972b0b _dispatch_lane_serial_drain + 791
12  libdispatch.dylib                   0x000000010c973784 _dispatch_lane_invoke + 428
13  libdispatch.dylib                   0x000000010c97d89a _dispatch_workloop_worker_thread + 733
14  libsystem_pthread.dylib             0x000000010cd5b60b _pthread_wqthread + 409
15  libsystem_pthread.dylib             0x000000010cd5b405 start_wqthread + 13

Running Erik on iOS 12.1 emit UI API called on a background thread warning.
Try to set like that but still has same issue.

DispatchQueue.main.async { [weak self] in
    (self?.browser.layoutEngine as? WebKitLayoutEngine)?.javaScriptQueue = .main
    self?.browser.visit(url: url, completionHandler: { document, error in
        consolePrint(document)
        consolePrint(error)
    })
}

[phimage]

This is an other part of the code that make this
wekbkit love to be acceded using main queue ;)
but I don't to block always the main queue

I think this code is executed to know when the page is loaded
and the queue is not javaScriptQueue but waitLoadingQueue

[fitch]

I seem to be getting this on iOS 13 still with the newest version of Erik:

Main Thread Checker: UI API called on a background thread: -[WKWebView navigationDelegate]
PID: 12577, TID: 584936, Thread name: (none), Queue name: ErikLoading, QoS: 0
Backtrace:
....

[eduhh94]

I have the same issue as fitch. Is there any fix yet?