@interface HACollectionViewFlowLayout : UICollectionViewFlowLayout
@end
#import "HACollectionViewFlowLayout.h"
@interface HACollectionViewFlowLayout ()
/// 缩放系数
@property (nonatomic, assign) CGFloat scaleFactor;
/// 这个值越大，缩放比例越不明显，最小不能小于item的宽度
@property (nonatomic, assign) CGFloat activeDistance;
@end
@implementation HACollectionViewFlowLayout
/// 初始化
- (instancetype)init {
self = [super init];
if (self) {
self.scaleFactor = 0.5;
self.activeDistance = 130;
}
return self;
}
/// 要展示的cell的属性
- (NSArray *)layoutAttributesForElementsInRect:(CGRect)rect {
NSArray *array = [super layoutAttributesForElementsInRect: rect];
CGRect frame = CGRectMake(self.collectionView.contentOffset.x, self.collectionView.contentOffset.y, self.collectionView.bounds.size.width, self.collectionView.bounds.size.height);
for (UICollectionViewLayoutAttributes *attribute in array) {
/// 确立cell相对于屏幕中央的距离
CGFloat distance = CGRectGetMidX(frame) - attribute.center.x;
/// 到中心位置的相对于x的比例,原则就是越近的越大，越远的越小。
CGFloat normalDistance = fabs(distance / self.activeDistance);
CGFloat scale = 1 - self.scaleFactor * normalDistance;
CGFloat alpha = 1 - normalDistance;
attribute.transform3D = CATransform3DMakeScale(scale, scale, 1);
attribute.alpha = alpha;
attribute.zIndex = alpha * 100;
}
return array;
}
/// 确定最终滚到的位置
- (CGPoint)targetContentOffsetForProposedContentOffset:(CGPoint)proposedContentOffset withScrollingVelocity:(CGPoint)velocity {
CGRect targetRect = CGRectMake(proposedContentOffset.x, proposedContentOffset.y, self.collectionView.bounds.size.width, self.collectionView.bounds.size.height);
NSArray *array = [super layoutAttributesForElementsInRect: targetRect];
CGFloat horizontalCenterX = proposedContentOffset.x + self.collectionView.bounds.size.width / 2.;
CGFloat offsetAdjustment = CGFLOAT_MAX;
for (UICollectionViewLayoutAttributes *attribute in array) {
CGFloat tempCenterX = attribute.center.x;
if (fabs(horizontalCenterX - tempCenterX) < fabs(offsetAdjustment)) {
offsetAdjustment = tempCenterX - horizontalCenterX;
}
}
return CGPointMake(proposedContentOffset.x + offsetAdjustment, proposedContentOffset.y);
}
- (BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds {
return YES;
}
@end
@interface HACycleHeadCollectionViewCell : UICollectionViewCell
@property (nonatomic, assign) NSInteger index;
/// 头像
@property (nonatomic, strong) UIImageView *imgHead;
@end
#import "HACycleHeadCollectionViewCell.h"
@implementation HACycleHeadCollectionViewCell
/// 初始化
- (instancetype)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
self.contentView.backgroundColor = [UIColor clearColor];
UIView *layerView = [[UIView alloc] initWithFrame: self.bounds];
layerView.backgroundColor = HAHexColor(DDDDDD);
layerView.layer.shadowColor = HAHexColor(DDDDDD).CGColor;
layerView.layer.shadowOffset = CGSizeMake(0, 0);
layerView.layer.shadowRadius = 2;
layerView.layer.cornerRadius = frame.size.width * 0.5;
layerView.layer.shadowOpacity = 0.7;
[self.contentView addSubview: layerView];
_imgHead = [[UIImageView alloc] initWithFrame: CGRectMake(0, 0, frame.size.width, frame.size.height)];
_imgHead.layer.cornerRadius = frame.size.width * 0.5;
_imgHead.layer.contentMode = UIViewContentModeScaleAspectFill;
_imgHead.layer.borderWidth = 2;
_imgHead.layer.borderColor = [UIColor whiteColor].CGColor;
_imgHead.layer.masksToBounds = YES;
[self.contentView addSubview: _imgHead];
}
return self;
}
@end
@interface HACycleHeadView : UIView
/// 自动滚动时间间隔，大于0开启自动轮播
@property (nonatomic, assign) CGFloat timerInterval;
@end
#import "HACycleHeadView.h"
#import "HACollectionViewFlowLayout.h"
#import "HACycleHeadCollectionViewCell.h"
static NSInteger sectionCount = 1000;
@interface HACycleHeadView ()
/// 存储图片
@property (nonatomic, strong) NSMutableArray *imageArr;
/// collectionView
@property (nonatomic, strong) UICollectionView *collectionView;
/// 计时器
@property (nonatomic, strong) NSTimer *timer;
@end
@implementation HACycleHeadView
/// 初始化
- (instancetype)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
self.backgroundColor = [UIColor clearColor];
_imageArr = [NSMutableArray arrayWithArray: @[
@"cycle_head_1", @"cycle_head_2",
@"cycle_head_3", @"cycle_head_4",
@"cycle_head_5", @"cycle_head_6",
@"cycle_head_7", @"cycle_head_8",
@"cycle_head_9", @"cycle_head_10",
@"cycle_head_11", @"cycle_head_12",
@"cycle_head_13", @"cycle_head_14",
@"cycle_head_15", @"cycle_head_16",
@"cycle_head_17", @"cycle_head_18",
@"cycle_head_19", @"cycle_head_20"
]];
HACollectionViewFlowLayout *layout = [[HACollectionViewFlowLayout alloc] init];
layout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
layout.minimumLineSpacing = -60;
layout.minimumInteritemSpacing = 0.0;
layout.itemSize = CGSizeMake(110, 110);
layout.sectionInset = UIEdgeInsetsMake(0, -30, 0, -30);
_collectionView = [[UICollectionView alloc] initWithFrame: CGRectMake((frame.size.width - 270) * 0.5, (frame.size.height - 110) * 0.5, 270, 110) collectionViewLayout: layout];
_collectionView.delegate = self;
_collectionView.dataSource = self;
_collectionView.showsHorizontalScrollIndicator = NO;
_collectionView.backgroundColor = [UIColor clearColor];
[_collectionView registerClass: [HACycleHeadCollectionViewCell class] forCellWithReuseIdentifier: @"HACycleHeadCollectionViewCell"];
[self addSubview: _collectionView];
if (@available(iOS 11.0, *)) {
_collectionView.contentInsetAdjustmentBehavior = UIScrollViewContentInsetAdjustmentNever;
}
}
return self;
}
- (void)layoutSubviews {
[super layoutSubviews];
if (!CGRectEqualToRect(_collectionView.frame, CGRectZero)) {
[_collectionView scrollToItemAtIndexPath: [NSIndexPath indexPathForRow: 0 inSection: sectionCount / 2] atScrollPosition: UICollectionViewScrollPositionCenteredHorizontally animated: NO];
}
}
/// 组个数
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
return sectionCount;
}
/// cell个数
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return _imageArr.count;
}
/// cell样式
- (__kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
HACycleHeadCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier: @"HACycleHeadCollectionViewCell" forIndexPath: indexPath];
cell.index = indexPath.row;
NSString *imageUrl = _imageArr[indexPath.row];
if ([imageUrl hasPrefix: @"http"]) {
[cell.imgHead ol_setHeadImageWithURL: imageUrl];
} else {
cell.imgHead.image = [UIImage imageNamed: imageUrl];
}
return cell;
}
/// 点击cell
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
NSIndexPath *index = [self indexPathForMiddleVisibleCell];
if (index.row == indexPath.row) {
return;
}
[self removeTimer];
_collectionView.userInteractionEnabled = NO;
[_collectionView scrollToItemAtIndexPath: indexPath atScrollPosition: UICollectionViewScrollPositionCenteredHorizontally animated: YES];
}
/// 滚动动画结束
- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {
_collectionView.userInteractionEnabled = YES;
[self addTimer];
}
/// scrollView开始拖拽
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {
[self removeTimer];
}
/// scrollView结束拖拽
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {
_collectionView.userInteractionEnabled = YES;
[self addTimer];
}
/// scrollView结束拖拽
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
_collectionView.userInteractionEnabled = YES;
[self addTimer];
}
/// 中间的indexPath
- (NSIndexPath *)indexPathForMiddleVisibleCell {
return [_collectionView indexPathForItemAtPoint: CGPointMake(_collectionView.contentOffset.x + _collectionView.frame.size.width / 2, 0)];
}
/// 计时器回调
- (void)timeHandle {
_collectionView.userInteractionEnabled = NO;
NSInteger itemsCount = _imageArr.count;
__block NSIndexPath *index = [self indexPathForMiddleVisibleCell];
[UIView animateWithDuration: 0.001 animations:^{
if (index.row == itemsCount - 1) {
index = [NSIndexPath indexPathForRow: index.row inSection: sectionCount / 2 - 1];
} else {
index = [NSIndexPath indexPathForRow: index.row inSection: sectionCount / 2];
}
[self.collectionView scrollToItemAtIndexPath: index atScrollPosition: UICollectionViewScrollPositionCenteredHorizontally animated: NO];
} completion:^(BOOL finished) {
if (index.row == itemsCount - 1) {
index = [NSIndexPath indexPathForRow: 0 inSection: sectionCount / 2];
} else {
index = [NSIndexPath indexPathForRow: index.row + 1 inSection: sectionCount / 2];
}
[self.collectionView scrollToItemAtIndexPath: index atScrollPosition: UICollectionViewScrollPositionCenteredHorizontally animated: YES];
}];
}
/// 设置自动滚动时间间隔
- (void)setTimerInterval:(CGFloat)timerInterval {
_timerInterval = timerInterval;
[self addTimer];
}
/// 添加计时器
- (void)addTimer {
if (_timerInterval > 0 && !_timer) {
_timer = [NSTimer scheduledTimerWithTimeInterval: _timerInterval target: self selector: @selector(timeHandle) userInfo: nil repeats: YES];
}
}
/// 移除计时器
- (void)removeTimer {
if (_timer) {
[_timer invalidate];
_timer = nil;
}
}
/// 移除
- (void)removeFromSuperview {
[super removeFromSuperview];
[self removeTimer];
}
@end
