NSProgress::completedUnitCount setter hangs

Question

• （void）URLSession:（NSURLSession*）会话任务：（NSURLSessionTask*）任务didSendBodyData:（int64_t）字节发送totalBytesSsent:（int64_t）totalBytesSenttotalBytesExpectedToSend:（int64_t）totalBytes ExpectedToSend{self.progress.completedUnitCount=发送的字节总数；^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^这挂在ios 9.0上有什么办法吗？？？

• （void）URLSession:（NSURLSession*）会话任务：（NSURLSessionTask*）任务didSendBodyData:（int64_t）字节发送totalBytesSsent:（int64_t）totalBytesSenttotalBytesExpectedToSend:（int64_t）totalBytes ExpectedToSend；在主线程上调用，这并不重要

（lldb）bt*线程#1:tid=0xd6e1，0x00000001984a0c6c libsystem_kernel.dylib semaphore_wait_trap + 8, queue = 'com.apple.main-thread', activity = 'send control actions', 1 messages, stop reason = signal SIGSTOP * frame #0: 0x00000001984a0c6c libsystem_kernel.dylib信号量wait_rap+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基础-[NSConcreteObservationBuffer _receiveBox:] + 248 frame #4: 0x00000001836180b0 Foundation _NSKVO1适配器交付+388帧#5:0x000000183617ea0 Foundation _NSKVO1AdaptorSlowDeliver + 264 frame #6: 0x0000000183523b84 Foundation-[NSKeyValueObservenceValueForKeyPath:ofObject:change：context:]+424帧#7:0x00000001834fdd4基础NSKeyValueNotifyObserver + 304 frame #8: 0x00000001834ff8fc Foundation NSKeyValueDidChange+404帧#9:0x00000001834ea114 Foundation -[NSObject(NSKeyValueObserverNotification) didChangeValueForKey:] + 120 frame #10: 0x000000018258fab0 CoreFoundation __53-[__NSArrayM enumerateObjects WithOptions:usingBlock:]_block_invoke+132帧#11:0x000000018258f9a8核心基础-[__NSArrayM enumerateObjectsWithOptions:usingBlock:] + 308 frame #12: 0x00000001836cc158 Foundation-[NSProgress _setValueForKeys:settingBlock:]+600帧#13:0x00000001836cc87c基础`-[NSProgress setCompletedUnitCount:]+124

PS：如果我避免将UIProgressView:：observedProgress设置为该NSProgress，它会正常工作！？

Answer 1

通过繁忙等待解决

-(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;
    });

附带的好处是对ios<9

Answer 2

Boy帮了我一把。我的应用程序在递增Progress.completedUnitCount时冻结了。（在主线程上。）我假设这会触发一个setter，因为它有一个副作用——移动进度条，这是这样做的全部原因。

我的Swift 4解决方案是这样结束通话：

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

我仍然不太明白为什么这样。。。和很多事情没什么不同。