NSProgress：：完全单位计数设置器挂起

Question

• (URLSession：(NSURLSession*)会话任务：(NSURLSessionTask*)任务didSendBodyData:(int64_t)bytesSent totalBytesSent:(int64_t)totalBytesSent { self.progress.completedUnitCount = totalBytesSent；^(Int64_t)bytesSent totalBytesSent：(NSURLSessionTask*)任务didSendBodyData：(Int64_t)bytesSent totalBytesSent：(Int64_t)totalBytesSent{self.progress.completedUnitCount=totalBytesSent；
• (URLSession)URLSession：(NSURLSession*)会话任务：(NSURLSessionTask*)任务didSendBodyData:(int64_t)bytesSent totalBytesSent:(int64_t)totalBytesSent

(lldb) bt *线程#1: tid = 0xd6e1，0x00000001984a0c6c libsystem_kernel.dylibsemaphore_wait_trap + 8, queue = 'com.apple.main-thread', activity = 'send control actions', 1 messages, stop reason = signal SIGSTOP * frame #0: 0x00000001984a0c6c libsystem_kernel.dylibsemaphore_wait_trap +8帧#1: 0x000000019857a97c libsystem_platform.dylib_os_semaphore_wait + 24 frame #2: 0x00000001007bd428 libdispatch.dylib_dispatch_barrier_sync_f_slow + 600帧#3: 0x00000001835af270 Foundation-[NSConcreteObservationBuffer _receiveBox:] + 248 frame #4: 0x00000001836180b0 Foundation_NSKVO1AdaptorDeliver + 388帧#5: 0x0000000183617ea0 Foundation_NSKVO1AdaptorSlowDeliver + 264 frame #6: 0x0000000183523b84 Foundation-NSKeyValueObservance observeValueForKeyPath:ofObject:change:context：+ 424帧#7: 0x0000000001834ffdd4基础NSKeyValueNotifyObserver + 304 frame #8: 0x00000001834ff8fc FoundationNSKeyValueDidChange+ 404框架#9: 0x00000001834ea114：0x000000018258f9a8 CoreFoundation-[__NSArrayM enumerateObjectsWithOptions:usingBlock:] + 308 frame #12: 0x00000001836cc158 Foundation-NSProgress _setValueForKeys:settingBlock：+ 600 frame #13: 0x00000001836cc87c Foundation`‘-NSProgress setCompletedUnitCount：+ 124

PS:如果我避免将UIProgressView：：观测进度设置为那个NSProgress，那么它工作得很好！？

Answer 1

忙着等待解决

-(void)showUploadingUI
{
myHardAssert([[NSThread currentThread] isMainThread], @"");
self.progressView.hidden = NO;
NSProgress *progress = urlsession.progress;
if( [self.progressView respondsToSelector:@selector(observedProgress)]) {
// this causes hang     self.progressView.observedProgress = progress;
}
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
    while(progress.completedUnitCount < progress.totalUnitCount) {
        dispatch_sync(dispatch_get_main_queue(), ^{
            self.progressView.progress = progress.fractionCompleted;
        });
        [NSThread sleepForTimeInterval:0.033];
    }
    dispatch_sync(dispatch_get_main_queue(), ^{
        self.progressView.progress = 1;
    });

……

副作用是ios <9的向后兼容性。

Answer 2

男孩帮了我的忙。我的应用程序在增加Progress.completedUnitCount时冻结了。(在主线程上)我假设这会触发一个设置器，因为有一个副作用-移动进度条，这是做它的全部原因。

我的Swift 4解决方案是把电话包装成这样：

DispatchQueue.global(qos: .utility).async {
    self._decompressionProgress.completedUnitCount += 1
}

我还是不太明白为什么这样做..。和很多事情没什么不同。