处理svip

keyBoard/Class/Pay/V/KBSvipFlowLayout.m

@@ -0,0 +1,90 @@
+//
+//  KBSvipFlowLayout.m
+//  keyBoard
+//
+//  SVIP 页面自定义布局，支持 Section 背景装饰视图
+//
+
+#import "KBSvipFlowLayout.h"
+#import "KBSvipBenefitBgView.h"
+
+static NSString * const kKBSvipDecorationViewKind = @"KBSvipBenefitBgDecoration";
+
+@interface KBSvipFlowLayout ()
+@property (nonatomic, strong) NSMutableArray<UICollectionViewLayoutAttributes *> *decorationAttributes;
+@end
+
+@implementation KBSvipFlowLayout
+
+- (instancetype)init {
+    if (self = [super init]) {
+        _decorationSection = 1; // 默认 Section 1 需要背景
+        [self registerClass:[KBSvipBenefitBgView class] forDecorationViewOfKind:kKBSvipDecorationViewKind];
+    }
+    return self;
+}
+
+- (void)prepareLayout {
+    [super prepareLayout];
+    
+    self.decorationAttributes = [NSMutableArray array];
+    
+    NSInteger numberOfSections = [self.collectionView numberOfSections];
+    if (self.decorationSection >= numberOfSections) { return; }
+    
+    NSInteger numberOfItems = [self.collectionView numberOfItemsInSection:self.decorationSection];
+    if (numberOfItems == 0) { return; }
+    
+    // 获取 Section Header 的布局属性
+    UICollectionViewLayoutAttributes *headerAttr = [self layoutAttributesForSupplementaryViewOfKind:UICollectionElementKindSectionHeader atIndexPath:[NSIndexPath indexPathForItem:0 inSection:self.decorationSection]];
+    
+    // 获取第一个和最后一个 item 的布局属性
+    UICollectionViewLayoutAttributes *firstItemAttr = [self layoutAttributesForItemAtIndexPath:[NSIndexPath indexPathForItem:0 inSection:self.decorationSection]];
+    UICollectionViewLayoutAttributes *lastItemAttr = [self layoutAttributesForItemAtIndexPath:[NSIndexPath indexPathForItem:numberOfItems - 1 inSection:self.decorationSection]];
+    
+    if (!firstItemAttr || !lastItemAttr) { return; }
+    
+    // 计算背景区域
+    UIEdgeInsets sectionInset = self.sectionInset;
+    if ([self.collectionView.delegate respondsToSelector:@selector(collectionView:layout:insetForSectionAtIndex:)]) {
+        sectionInset = [(id<UICollectionViewDelegateFlowLayout>)self.collectionView.delegate collectionView:self.collectionView layout:self insetForSectionAtIndex:self.decorationSection];
+    }
+    
+    CGFloat minY = CGRectGetMinY(headerAttr.frame);
+    CGFloat maxY = CGRectGetMaxY(lastItemAttr.frame) + 16; // 底部留 16 间距
+    CGFloat x = sectionInset.left;
+    CGFloat width = self.collectionView.bounds.size.width - sectionInset.left - sectionInset.right;
+    
+    CGRect decorationFrame = CGRectMake(x, minY, width, maxY - minY);
+    
+    UICollectionViewLayoutAttributes *decorationAttr = [UICollectionViewLayoutAttributes layoutAttributesForDecorationViewOfKind:kKBSvipDecorationViewKind withIndexPath:[NSIndexPath indexPathForItem:0 inSection:self.decorationSection]];
+    decorationAttr.frame = decorationFrame;
+    decorationAttr.zIndex = -1; // 放在最底层
+    
+    [self.decorationAttributes addObject:decorationAttr];
+}
+
+- (NSArray<__kindof UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect {
+    NSMutableArray *attrs = [[super layoutAttributesForElementsInRect:rect] mutableCopy];
+    
+    for (UICollectionViewLayoutAttributes *decorationAttr in self.decorationAttributes) {
+        if (CGRectIntersectsRect(rect, decorationAttr.frame)) {
+            [attrs addObject:decorationAttr];
+        }
+    }
+    
+    return attrs;
+}
+
+- (UICollectionViewLayoutAttributes *)layoutAttributesForDecorationViewOfKind:(NSString *)elementKind atIndexPath:(NSIndexPath *)indexPath {
+    if ([elementKind isEqualToString:kKBSvipDecorationViewKind]) {
+        for (UICollectionViewLayoutAttributes *attr in self.decorationAttributes) {
+            if (attr.indexPath.section == indexPath.section) {
+                return attr;
+            }
+        }
+    }
+    return [super layoutAttributesForDecorationViewOfKind:elementKind atIndexPath:indexPath];
+}
+
+@end