照着下面的步骤,添加 代理方法 和.h.m方法,就可以实现下图的效果
添加的代理 EqualSpaceFlowLayoutDelegate
EqualSpaceFlowLayout *flowLayout = [[EqualSpaceFlowLayout alloc] init];
flowLayout.delegate = self;
新建EqualSpaceFlowLayoutDelegate 下面是.h代码
#import@protocol EqualSpaceFlowLayoutDelegate@end@interface EqualSpaceFlowLayout : UICollectionViewFlowLayout@property (nonatomic,weak) iddelegate;
@end
新建EqualSpaceFlowLayoutDelegate 下面是.m代码
#import "EqualSpaceFlowLayout.h"
@interface EqualSpaceFlowLayout()
@property (nonatomic, strong) NSMutableArray *itemAttributes;
@end
@implementation EqualSpaceFlowLayout
- (id)init
{
if (self = [super init]) {
self.scrollDirection = UICollectionViewScrollDirectionVertical;
self.minimumInteritemSpacing = 10;
self.minimumLineSpacing = 10;
self.sectionInset = UIEdgeInsetsMake(20, 15, 15, 15);
}
return self;
}
#pragma mark - Methods to Override
- (void)prepareLayout
{
[super prepareLayout];
NSInteger itemCount = [[self collectionView] numberOfItemsInSection:0];
self.itemAttributes = [NSMutableArray arrayWithCapacity:itemCount];
CGFloat xOffset = self.sectionInset.left;
CGFloat yOffset = self.sectionInset.top;
CGFloat xNextOffset = self.sectionInset.left;
for (NSInteger idx = 0; idx < itemCount; idx++) {
NSIndexPath *indexPath = [NSIndexPath indexPathForItem:idx inSection:0];
CGSize itemSize = [self.delegate collectionView:self.collectionView layout:self sizeForItemAtIndexPath:indexPath];
xNextOffset+=(self.minimumInteritemSpacing + itemSize.width);
if (xNextOffset > [self collectionView].bounds.size.width - self.sectionInset.right) {
xOffset = self.sectionInset.left;
xNextOffset = (self.sectionInset.left + self.minimumInteritemSpacing + itemSize.width);
yOffset += (itemSize.height + self.minimumLineSpacing);
}
else
{
xOffset = xNextOffset - (self.minimumInteritemSpacing + itemSize.width);
}
UICollectionViewLayoutAttributes *layoutAttributes =
[UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
layoutAttributes.frame = CGRectMake(xOffset, yOffset, itemSize.width, itemSize.height);
[_itemAttributes addObject:layoutAttributes];
}
}
- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath
{
return (self.itemAttributes)[indexPath.item];
}
- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
{
return [self.itemAttributes filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(UICollectionViewLayoutAttributes *evaluatedObject, NSDictionary *bindings) {
return CGRectIntersectsRect(rect, [evaluatedObject frame]);
}]];
}
- (BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds
{
return NO;
}
@end
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