UI无响应

[SonglinYu1230]

下面这种方式调用会出现UI无响应的问题，麻烦有时间了帮忙看下。

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        dispatch_async(dispatch_get_main_queue(), ^{
            SynchronizedUIActionSheet * synActionSheet = [[SynchronizedUIActionSheet alloc] init];
            synActionSheet.titles = [NSArray arrayWithObjects:@"aaa", @"bbb", @"ccc", @"ddd", nil];
            synActionSheet.destructiveButtonIndex = 1;
            synActionSheet.cancelButtonIndex = 3;
            NSUInteger result = [synActionSheet showInView:self.view];
            NSLog(@"result = %d", result);
        });
    });