Question

我的问题可能有一个非常明显的答案，我很想念。我有一个像这样的NSURLConnection：

- (void)viewDidLoad
{
[super viewDidLoad];

NSString *urlstring = [NSString stringWithFormat:@"http://127.0.0.1:8000/image/"];
NSMutableURLRequest *postRequest = [NSMutableURLRequest
                                    requestWithURL:[NSURL URLWithString:urlstring]
                                    cachePolicy:NSURLRequestUseProtocolCachePolicy
                                    timeoutInterval:30.0];
[postRequest setHTTPMethod:@"POST"];
self.firstConnection = [[NSURLConnection alloc] initWithRequest:postRequest delegate:self];

}

-(void)connectionDidFinishLoading:(NSURLConnection*)connection
{
if (connection == _firstConnection){
    // Deal with the data
    [self getImages];
    [self.collectionView reloadData];
}

-(void)getImages
{
NSError *error;
NSMutableArray* images= [NSJSONSerialization JSONObjectWithData:_data options:0 error:&error];
NSUInteger arrayLength = [images count];


dressURLS = [[NSMutableArray alloc] init];
for (NSInteger i=0;i<arrayLength;i++)
{
    NSString *temp = [images[i] objectForKey:@"image"];
    [dressURLS addObject:temp];
}
}

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{

static NSString *identifier = @"Cell";
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
UIImageView *dressImageView = (UIImageView *)[cell viewWithTag:100];

NSString *clothesurl = dressURLS[i]; //i value????
NSString *url =[NSString stringWithFormat:@"http://127.0.0.1:8000/media/%@",clothesurl];
NSURL *imageURL = [NSURL URLWithString:url];

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{

    NSData *imageData = [NSData dataWithContentsOfURL:imageURL];

    dispatch_async(dispatch_get_main_queue(), ^{
        // Update the UI
        dressImageView.image = [UIImage imageWithData:imageData];
    });
});

return cell;

}

我知道，代码非常混乱。这是它的工作原理。 viewDidLoad初始化连接。它转到connectionDidFinishLoading，其中getImages处理我必须操作并存储在数组中的数据。然后我使用reloadData方法转到Collection View，这是我遇到各种问题的地方。

我需要访问dressURLS[i]的元素，其中i = 0,1,2,3。但是，由于a的事实，循环非常复杂。集合视图重新加载b。异步调度。我无法让i从0循环到

任何使这不那么复杂的解决方案？

Answer 1

-(void)connectionDidFinishLoading:(NSURLConnection*)connection
{
if (connection == _firstConnection){
    // Deal with the data
    [self getImages];
    [collectionView reloaddata]; // or self.collectionView (for property)
}

}

“讨论调用此方法可重新加载集合视图中的所有项目。这会导致集合视图丢弃任何当前可见的项目并重新显示它们。“ - Apple

Answer 2

你可以第一次使用BOOL＆amp;第二次检查条件＆amp;通过重新加载集合视图来显示图像。

在connectionDidFinishLoading之后返回到collectionView函数

2 个答案: