134 lines
5.6 KiB
Objective-C
134 lines
5.6 KiB
Objective-C
//
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// KBSvipFlowLayout.m
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// keyBoard
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//
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// SVIP 页面自定义布局，支持多个 Section 背景装饰视图
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//
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#import "KBSvipFlowLayout.h"
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#import "KBSvipBenefitBgView.h"
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static NSString * const kKBSvipOuterBgKind = @"KBSvipOuterBgDecoration"; // 外层大背景（18圆角，包裹全部）
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static NSString * const kKBSvipBenefitBgKind = @"KBSvipBenefitBgDecoration"; // 内层权益背景（15圆角）
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#pragma mark - 外层大背景视图（18圆角，包裹订阅选项+权益列表）
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@interface KBSvipOuterBgView : UICollectionReusableView
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@end
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@implementation KBSvipOuterBgView
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- (instancetype)initWithFrame:(CGRect)frame {
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if (self = [super initWithFrame:frame]) {
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self.backgroundColor = [UIColor whiteColor];
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self.layer.cornerRadius = 18;
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self.layer.masksToBounds = YES;
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}
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return self;
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}
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@end
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#pragma mark - KBSvipFlowLayout
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@interface KBSvipFlowLayout ()
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@property (nonatomic, strong) NSMutableArray<UICollectionViewLayoutAttributes *> *decorationAttributes;
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@end
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@implementation KBSvipFlowLayout
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- (instancetype)init {
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if (self = [super init]) {
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_decorationSection = 1; // Section 1 是权益列表
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[self registerClass:[KBSvipOuterBgView class] forDecorationViewOfKind:kKBSvipOuterBgKind];
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[self registerClass:[KBSvipBenefitBgView class] forDecorationViewOfKind:kKBSvipBenefitBgKind];
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}
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return self;
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}
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- (void)prepareLayout {
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[super prepareLayout];
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self.decorationAttributes = [NSMutableArray array];
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NSInteger numberOfSections = [self.collectionView numberOfSections];
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if (numberOfSections < 2) { return; }
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NSInteger itemCount0 = [self.collectionView numberOfItemsInSection:0];
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NSInteger itemCount1 = [self.collectionView numberOfItemsInSection:1];
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if (itemCount0 == 0 || itemCount1 == 0) { return; }
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// 获取 Section 0 第一个 item
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UICollectionViewLayoutAttributes *firstItemAttr = [self layoutAttributesForItemAtIndexPath:[NSIndexPath indexPathForItem:0 inSection:0]];
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// 获取 Section 1 Header
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UICollectionViewLayoutAttributes *benefitHeaderAttr = [self layoutAttributesForSupplementaryViewOfKind:UICollectionElementKindSectionHeader atIndexPath:[NSIndexPath indexPathForItem:0 inSection:1]];
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// 获取 Section 1 最后一个 item
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UICollectionViewLayoutAttributes *lastBenefitAttr = [self layoutAttributesForItemAtIndexPath:[NSIndexPath indexPathForItem:itemCount1 - 1 inSection:1]];
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if (!firstItemAttr || !benefitHeaderAttr || !lastBenefitAttr) { return; }
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UIEdgeInsets sectionInset0 = [self insetForSection:0];
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UIEdgeInsets sectionInset1 = [self insetForSection:1];
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// 1. 外层大背景（18圆角）：从 Section 0 顶部到 Section 1 底部
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{
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CGFloat minY = CGRectGetMinY(firstItemAttr.frame) - sectionInset0.top;
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CGFloat maxY = CGRectGetMaxY(lastBenefitAttr.frame) + 16;
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CGFloat x = sectionInset0.left;
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CGFloat width = self.collectionView.bounds.size.width - sectionInset0.left - sectionInset0.right;
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CGRect frame = CGRectMake(x, minY, width, maxY - minY);
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UICollectionViewLayoutAttributes *attr = [UICollectionViewLayoutAttributes layoutAttributesForDecorationViewOfKind:kKBSvipOuterBgKind withIndexPath:[NSIndexPath indexPathForItem:0 inSection:0]];
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attr.frame = frame;
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attr.zIndex = -2; // 最底层
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[self.decorationAttributes addObject:attr];
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}
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// 2. 内层权益背景（15圆角）：从 Section 1 Header 到 Section 1 底部，左右距离外层 8px
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{
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CGFloat minY = CGRectGetMinY(benefitHeaderAttr.frame);
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CGFloat maxY = CGRectGetMaxY(lastBenefitAttr.frame) + 16;
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CGFloat x = sectionInset0.left + 8; // 距离外层左边 8px
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CGFloat width = self.collectionView.bounds.size.width - sectionInset0.left - sectionInset0.right - 16; // 左右各 8px
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CGRect frame = CGRectMake(x, minY, width, maxY - minY);
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UICollectionViewLayoutAttributes *attr = [UICollectionViewLayoutAttributes layoutAttributesForDecorationViewOfKind:kKBSvipBenefitBgKind withIndexPath:[NSIndexPath indexPathForItem:0 inSection:1]];
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attr.frame = frame;
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attr.zIndex = -1; // 在外层背景之上
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[self.decorationAttributes addObject:attr];
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}
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}
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- (UIEdgeInsets)insetForSection:(NSInteger)section {
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UIEdgeInsets sectionInset = self.sectionInset;
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if ([self.collectionView.delegate respondsToSelector:@selector(collectionView:layout:insetForSectionAtIndex:)]) {
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sectionInset = [(id<UICollectionViewDelegateFlowLayout>)self.collectionView.delegate collectionView:self.collectionView layout:self insetForSectionAtIndex:section];
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}
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return sectionInset;
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}
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- (NSArray<__kindof UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect {
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NSMutableArray *attrs = [[super layoutAttributesForElementsInRect:rect] mutableCopy];
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for (UICollectionViewLayoutAttributes *decorationAttr in self.decorationAttributes) {
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if (CGRectIntersectsRect(rect, decorationAttr.frame)) {
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[attrs addObject:decorationAttr];
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}
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}
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return attrs;
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}
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- (UICollectionViewLayoutAttributes *)layoutAttributesForDecorationViewOfKind:(NSString *)elementKind atIndexPath:(NSIndexPath *)indexPath {
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for (UICollectionViewLayoutAttributes *attr in self.decorationAttributes) {
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if ([attr.representedElementKind isEqualToString:elementKind] && attr.indexPath.section == indexPath.section) {
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return attr;
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}
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}
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return [super layoutAttributesForDecorationViewOfKind:elementKind atIndexPath:indexPath];
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}
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@end
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