直接分出到子线程中

[NSThread detachNewThreadSelector:@selector(setupImageResampling) toTarget:self withObject:nil];

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
        [NSThread sleepForTimeInterval:.5f];
        
        while ([device isAdjustingFocus] ||
               [device isAdjustingExposure] ||
               [device isAdjustingWhiteBalance]);
        
        dispatch_async(dispatch_get_main_queue(), ^{
            //
            // remove focus view and focus subview animated
            //
            [cameraFocusView stopAnimation];
        });
    });

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0), ^{
        [NSThread sleepForTimeInterval:timeInterval];
        dispatch_async(dispatch_get_main_queue(), ^{
            [self removeSlideFromSuperview:YES
                              withDuration:.5
                                   originY:[self finalPosition]
                                completion:completion];
        });
    });

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//新建一个队列
    dispatch_queue_t concurrentQueue =dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    //执行concurrentQueue队列
    dispatch_async(concurrentQueue, ^{
        __block UIImage *image = nil;
        dispatch_sync(concurrentQueue, ^{
            ASSETHELPER.bReverse = YES;
            [ASSETHELPER getGroupList:^(NSArray *aGroups) {
                for (ALAssetsGroup *group in aGroups) {
                    NSString *groupName = [group valueForProperty:ALAssetsGroupPropertyName];
                    if ([ALBUM_NAME isEqualToString:groupName]) {
                        flag = YES;
                        break;
                    }
                    nIndex++;
                }
                
                if (flag) {
                    [ASSETHELPER getPhotoListOfGroupByIndex:nIndex result:^(NSArray *aPhotos) {
                        if ([aPhotos count]>0) {
                            ALAsset*  assetPhotos = [aPhotos objectAtIndex:0];
                            image  = [ASSETHELPER  getImageFromAsset:assetPhotos  type:ASSET_PHOTO_THUMBNAIL];
                        }
                    }];
                }
    
            }];

        
        });
        dispatch_sync(dispatch_get_main_queue(), ^{
            /* 在主线程里面显示图片*/
            if (image != nil){
                CGRect photoFrame =  CGRectMake(8,6, _albumButton.frame.size.width-16, _albumButton.frame.size.height-16);
                UIImageView *imgView = [[UIImageView alloc] initWithFrame:photoFrame];
                imgView.image = image;
                [_albumButton addSubview:imgView];
            } else {
                NSLog(@"从相册中取最后一张图片失败. Nothing to display.");
            } });
    
    
    });

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void runOnMainQueueWithoutDeadlocking(void (^block)(void))
{
    if ([NSThread isMainThread])
    {
        block();
    }
    else
    {
        dispatch_sync(dispatch_get_main_queue(), block);
    }
}

void runSynchronouslyOnVideoProcessingQueue(void (^block)(void))
{
    dispatch_queue_t videoProcessingQueue = [GPUImageContext sharedContextQueue];
#if !OS_OBJECT_USE_OBJC
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
    if (dispatch_get_current_queue() == videoProcessingQueue)
#pragma clang diagnostic pop
#else
    if (dispatch_get_specific([GPUImageContext contextKey]))
#endif
    {
        block();
    }else
    {
        dispatch_sync(videoProcessingQueue, block);
    }
}

void runAsynchronouslyOnVideoProcessingQueue(void (^block)(void))
{
    dispatch_queue_t videoProcessingQueue = [GPUImageContext sharedContextQueue];
    
#if !OS_OBJECT_USE_OBJC
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
    if (dispatch_get_current_queue() == videoProcessingQueue)
#pragma clang diagnostic pop
#else
    if (dispatch_get_specific([GPUImageContext contextKey]))
#endif
    {
        block();
    }else
    {
        dispatch_async(videoProcessingQueue, block);
    }
}

void runSynchronouslyOnContextQueue(GPUImageContext *context, void (^block)(void))
{
    dispatch_queue_t videoProcessingQueue = [context contextQueue];
#if !OS_OBJECT_USE_OBJC
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
    if (dispatch_get_current_queue() == videoProcessingQueue)
#pragma clang diagnostic pop
#else
        if (dispatch_get_specific([GPUImageContext contextKey]))
#endif
        {
            block();
        }else
        {
            dispatch_sync(videoProcessingQueue, block);
        }
}

void runAsynchronouslyOnContextQueue(GPUImageContext *context, void (^block)(void))
{
    dispatch_queue_t videoProcessingQueue = [context contextQueue];
    
#if !OS_OBJECT_USE_OBJC
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
    if (dispatch_get_current_queue() == videoProcessingQueue)
#pragma clang diagnostic pop
#else
        if (dispatch_get_specific([GPUImageContext contextKey]))
#endif
        {
            block();
        }else
        {
            dispatch_async(videoProcessingQueue, block);
        }
}

void reportAvailableMemoryForGPUImage(NSString *tag)
{    
    if (!tag)
        tag = @"Default";
    
    struct task_basic_info info;
    
    mach_msg_type_number_t size = sizeof(info);
    
    kern_return_t kerr = task_info(mach_task_self(),
                                   
                                   TASK_BASIC_INFO,
                                   
                                   (task_info_t)&info,
                                   
                                   &size);    
    if( kerr == KERN_SUCCESS ) {        
        NSLog(@"%@ - Memory used: %u", tag, (unsigned int)info.resident_size); //in bytes
    } else {        
        NSLog(@"%@ - Error: %s", tag, mach_error_string(kerr));        
    }    
}

IOS UI 线程与非 UI 线程代码收集