ios - 如何将图像从NSDictionary获取到UICollectionView iOS？

Question

我有一本词典，图片很少。它的结构如下。
NSDictionary

 |__ bed
 |    |__ 351.jpg
 |    |__ 352.jpg
 |__ pillow
 |    |__ pillow1.png
      |__ pillow2.png 

我试图将其添加到 colloectioview中，如下所示。

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return self.imagesDictionary.count;
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return [[[self.imagesDictionary allValues] objectAtIndex:section] count];
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath 
{
    // Setup cell identifier
    static NSString *cellIdentifier = @"ImageCell";
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
    UIImageView *recipeImageView = (UIImageView *)[cell viewWithTag:100];
    UIImage *image = (UIImage*)[[(NSArray*)[self.imagesDictionary allValues] objectAtIndex:indexPath.row] objectAtIndex:indexPath.row];
    recipeImageView.image = image;
    [cell addSubview:recipeImageView];
    // Return the cell
    return cell;
}

当我运行此代码时，我得到了2个部分，并且所有部分都具有相同的图像(section1-351.jpg，枕头2.jpg，section2-351.jpg，枕头2.jpg)。我怎样才能解决这个问题。

提前致谢!

Answer 1

这里的问题可能源于NSDictionary不是有序容器的事实。如果要按索引从中选择项目，则需要先对键进行排序，然后再将它们编入索引。尝试这样的事情:

- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return self.imagesDictionary.count;
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    NSArray* sortedSections = [[self.imagesDictionary allKeys] sortedArrayUsingSelector: @selector(compare:)];
    NSString* key = sortedSections[section];
    NSArray* images = self.imagesDictionary[key];
    return images.count;
}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    // Setup cell identifier
    static NSString *cellIdentifier = @"ImageCell";
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
    UIImageView *recipeImageView = (UIImageView *)[cell viewWithTag:100];
    NSArray* sortedSections = [[self.imagesDictionary allKeys] sortedArrayUsingSelector: @selector(compare:)];
    NSString* key = sortedSections[[indexPath indexAtPosition: 0]];
    NSArray* images = self.imagesDictionary[key];
    UIImage *image = (UIImage*) images[[indexPath indexAtPosition: 1]];
    recipeImageView.image = image;
    [cell addSubview:recipeImageView];
    // Return the cell
    return cell;
}