调度不能正常工作

Question

我尝试在后台获取一些数据并在搜索栏中键入时刷新表格视图，这是我当前的代码：

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        Games * game = [[Games alloc] init];
        NSArray * temp = [game comingSoonWithPlatform:@"pc" header:[game gameHeader] parseLink:[game gameComingSoonListLinkWithPlatform:@"pc"]];
        self.searchArray = [temp valueForKey:@"results"];
        [self.tableView reloadData];
    });
}

我做错了什么？如果我在搜索栏中再输入一个词，或者如果我点击取消按钮，它会刷新并且数据会出现在表格视图中。

Answer 1

对[self.tableView reloadData];的调用必须在主线程上。替换行

[self.tableView reloadData];

和

dispatch_async(dispatch_get_main_queue(), ^{
    [self.tableView reloadData];
});

Answer 2

您正在从主线程创建后台线程，在进行任何处理后您需要切换到主线程以更新 UI。

例如，您可以在下面的方法中编写代码，如-

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText
{
    // [activityIndicator startAnimating];
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

        // do your background code here
        Games * game = [[Games alloc] init];
        NSArray * temp = [game comingSoonWithPlatform:@"pc" header:[game gameHeader] parseLink:[game gameComingSoonListLinkWithPlatform:@"pc"]];
        self.searchArray = [temp valueForKey:@"results"];

        dispatch_sync(dispatch_get_main_queue(), ^{
            // you are now on the main queue again, update ui here  
        //[activityIndicator stopAnimating];
        [self.tableView reloadData];
        });
    });
}

调度不能正常工作

Dispatch doesn't work properly

objective-c

uitableview

grand-central-dispatch

ios

searchbar