多线程的使用之dispatchasync

处理耗时任务

两个同步搞定

• 一般处理数据花费时间较长，但是最后刷新ui在主线程 处理代码如下：

        dispatch_sync(dispatch_get_global_queue(0, 0), ^{
            NSArray * array = @[
                                @{@"img": @"https://camo.githubusercontent.com/be57d040ec0ce5d6467fb73564c6bcb6c76d5a7b/687474703a2f2f6472696262626c652e73332e616d617a6f6e6177732e636f6d2f75736572732f363431302f73637265656e73686f74732f313235343433392f666f726d2d616e696d6174696f6e2d5f6769665f2e676966", @"intro": @"如果再看到关于纯代码,xib或storyboard,使用哪种方式进行UI布局更合适的讨论,请推荐他们先试用下 Masonry. Masonry,像xib一样快速,同时拥有作为纯代码方式的灵活性 — github关注度 7800 + 是有原因的!"},
                                @{@"img": @"https://camo.githubusercontent.com/be57d040ec0ce5d6467fb73564c6bcb6c76d5a7b/687474703a2f2f6472696262626c652e73332e616d617a6f6e6177732e636f6d2f75736572732f363431302f73637265656e73686f74732f313235343433392f666f726d2d616e696d6174696f6e2d5f6769665f2e676966", @"intro": @"无论如何,你总是需要一个提示框."},
                                @{@"img": @"https://camo.githubusercontent.com/be57d040ec0ce5d6467fb73564c6bcb6c76d5a7b/687474703a2f2f6472696262626c652e73332e616d617a6f6e6177732e636f6d2f75736572732f363431302f73637265656e73686f74732f313235343433392f666f726d2d616e696d6174696f6e2d5f6769665f2e676966", @"intro": @"SVProgressHUD是简单易用的显示器,用于指示一个持续进行的任务的进度."},
                                @{@"img": @"https://camo.githubusercontent.com/be57d040ec0ce5d6467fb73564c6bcb6c76d5a7b/687474703a2f2f6472696262626c652e73332e616d617a6f6e6177732e636f6d2f75736572732f363431302f73637265656e73686f74732f313235343433392f666f726d2d616e696d6174696f6e2d5f6769665f2e676966", @"intro": @"RestKit 是一个用于更好支持RESTful风格服务器接口的iOS库,可直接将联网获取的json/xml数据转换为iOS对象."},
                                @{@"img": @"https://camo.githubusercontent.com/be57d040ec0ce5d6467fb73564c6bcb6c76d5a7b/687474703a2f2f6472696262626c652e73332e616d617a6f6e6177732e636f6d2f75736572732f363431302f73637265656e73686f74732f313235343433392f666f726d2d616e696d6174696f6e2d5f6769665f2e676966", @"intro": @"FMDB 是SQLite的Objective-C封装库."},
                                @{@"img": @"https://camo.githubusercontent.com/be57d040ec0ce5d6467fb73564c6bcb6c76d5a7b/687474703a2f2f6472696262626c652e73332e616d617a6f6e6177732e636f6d2f75736572732f363431302f73637265656e73686f74732f313235343433392f666f726d2d616e696d6174696f6e2d5f6769665f2e676966", @"intro": @"Pop 是一个可扩展的动画引擎,可用于实现任意iOS对象的任意属性的动态变化,支持一般动画,弹性动画和渐变动画三种类型."},
                                @{@"img": @"https://camo.githubusercontent.com/be57d040ec0ce5d6467fb73564c6bcb6c76d5a7b/687474703a2f2f6472696262626c652e73332e616d617a6f6e6177732e636f6d2f75736572732f363431302f73637265656e73686f74732f313235343433392f666f726d2d616e696d6174696f6e2d5f6769665f2e676966", @"intro": @"高度可定制的应用欢迎页通用解决方案,可高度定制,不要仅限于现有的demo"},
                                @{@"img": @"https://camo.githubusercontent.com/be57d040ec0ce5d6467fb73564c6bcb6c76d5a7b/687474703a2f2f6472696262626c652e73332e616d617a6f6e6177732e636f6d2f75736572732f363431302f73637265656e73686f74732f313235343433392f666f726d2d616e696d6174696f6e2d5f6769665f2e676966", @"intro": @"JVFloatLabeledTextField 是注重用户体验的”浮动标签模式”(Float Label Patter)的第一个实现,可以有效解决移动设备上进行表单输入时,无法边看表单提示边进行输入的困境,用户体验非常好."},
                                @{@"img": @"https://camo.githubusercontent.com/be57d040ec0ce5d6467fb73564c6bcb6c76d5a7b/687474703a2f2f6472696262626c652e73332e616d617a6f6e6177732e636f6d2f75736572732f363431302f73637265656e73686f74732f313235343433392f666f726d2d616e696d6174696f6e2d5f6769665f2e676966", @"intro": @"用于为应用添加常用的上拉加载更多与下拉刷新效果,适用 UIScrollView、UITableView、UICollectionView、UIWebView."},
                                @{@"img": @"https://camo.githubusercontent.com/be57d040ec0ce5d6467fb73564c6bcb6c76d5a7b/687474703a2f2f6472696262626c652e73332e616d617a6f6e6177732e636f6d2f75736572732f363431302f73637265656e73686f74732f313235343433392f666f726d2d616e696d6174696f6e2d5f6769665f2e676966", @"intro": @"iOS-blur使用一种巧妙的方式,为任意视图添加一种非常奇妙的模糊效果."}
                                
                                ];
            
            [array enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
                LPModel * model = [LPModel new];
                model.imgUrl = @"https://raw.githubusercontent.com/ealeksandrov/EAIntroView/master/Screenshot02.png";
                model.content = [obj objectForKey:@"intro"];
                [self.dataList addObject:model];
                
            }];
            dispatch_async(dispatch_get_main_queue(), ^{
               
                [self.tableView reloadData];
            });
        });