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56 lines
1.8 KiB
56 lines
1.8 KiB
4 years ago
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//
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// TFCollectionViewFlowLayout.m
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// TFPhotoBrowser
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//
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// Created by zhengwenming on 2018/6/11.
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// Copyright © 2018年 zhengwenming. All rights reserved.
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//
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#import "TFCollectionViewFlowLayout.h"
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@implementation TFCollectionViewFlowLayout
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- (void)prepareLayout
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{
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[super prepareLayout];
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self.scrollDirection = UICollectionViewScrollDirectionHorizontal;
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CGSize size = self.collectionView.bounds.size;
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self.itemSize = CGSizeMake(size.width, size.height);
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self.minimumLineSpacing = 0;
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self.minimumInteritemSpacing = 10;
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}
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- (NSArray<UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect
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{
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NSArray<UICollectionViewLayoutAttributes *> *layoutAttsArray = [[NSArray alloc] initWithArray:[super layoutAttributesForElementsInRect:rect] copyItems:YES];
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CGFloat centerX = self.collectionView.contentOffset.x + self.collectionView.bounds.size.width/2.0;
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__block CGFloat min = CGFLOAT_MAX;
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__block NSUInteger minIdx;
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[layoutAttsArray enumerateObjectsUsingBlock:^(UICollectionViewLayoutAttributes * _Nonnull obj, NSUInteger index, BOOL * _Nonnull stop) {
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if (ABS(centerX - obj.center.x) < min) {
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min = ABS(centerX - obj.center.x);
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minIdx = index;
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}
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}];
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[layoutAttsArray enumerateObjectsUsingBlock:^(UICollectionViewLayoutAttributes * _Nonnull obj, NSUInteger index, BOOL * _Nonnull stop) {
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if (minIdx - 1 == index) {
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obj.center = CGPointMake(obj.center.x - self.imgaeGap, obj.center.y);
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}
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if (minIdx + 1 == index) {
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obj.center = CGPointMake(obj.center.x + self.imgaeGap, obj.center.y);
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}
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}];
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return layoutAttsArray;
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}
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- (BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds
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{
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return YES;
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}
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@end
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