江苏电力建设网站,装修平台哪个最好,罗湖网站建设58,免费的成品网站效果图 计算逻辑
设定在中间展示的size#xff0c;即正常size#xff0c;然后设置水平和竖直方向上的margin, 在view的origin和scrollView的contentoffset相等的时候#xff0c;即 视图处在正中间的时候#xff0c;最大#xff0c;然后通过计算其他视图的origin和scrollV…效果图 计算逻辑
设定在中间展示的size即正常size然后设置水平和竖直方向上的margin, 在view的origin和scrollView的contentoffset相等的时候即 视图处在正中间的时候最大然后通过计算其他视图的origin和scrollView.contentoffset 的距离设置大小和contentoffset这个位置的frame的距离为一个视图宽度的时候达到最小size,即最大size减去margin。然后通过计算该视图的origin和 contentffset的差的绝对值即距离 占 视图宽度的比例计算需要缩小的size
核心代码
//
// LBHorizontalLoopView.m
// LBHorizontalLoopView
//
// Created by liubo on 2021/8/29.
//#import LBMiddleExpandLoopView.hinterface LBMiddleExpandLoopView ()UIScrollViewDelegateproperty (nonatomic, strong, readwrite) LBMiddleExpandLoopViewBaseCell *currentCell;property (nonatomic, assign, readwrite) NSInteger currentSelectIndex;// 实际的个数
property (nonatomic, assign) NSInteger realCount;// 显示的个数
property (nonatomic, assign) NSInteger showCount;// 定时器
property (nonatomic, weak) NSTimer *timer;
property (nonatomic, assign) NSInteger timerIndex;// 当前显示的cell大小
property (nonatomic, assign) CGSize cellSize;property (nonatomic, strong) NSMutableDictionary *viewClsDict;
property (nonatomic, strong) NSMutableArray *visibleCells;
property (nonatomic, strong) NSMutableArray *reusableCells;
property (nonatomic, assign) NSRange visibleRange;// 处理xib加载时导致的尺寸不准确问题
property (nonatomic, assign) CGSize originSize;endimplementation LBMiddleExpandLoopView#pragma mark - Life Cycle
- (instancetype)initWithFrame:(CGRect)frame {if (self [super initWithFrame:frame]) {[self initialization];}return self;
}- (instancetype)initWithCoder:(NSCoder *)aDecoder {if (self [super initWithCoder:aDecoder]) {[self initialization];}return self;
}- (void)layoutSubviews {[super layoutSubviews];if (CGSizeEqualToSize(self.originSize, CGSizeZero)) return;// 解决xib加载时导致的布局错误问题if (!CGSizeEqualToSize(self.bounds.size, self.originSize)) {[self updateScrollViewAndCellSize];}
}// 解决当父视图释放时当前视图因为NSTimer强引用而导致的不能释放
- (void)willMoveToSuperview:(UIView *)newSuperview {if (!newSuperview) {[self stopTimer];}
}- (void)dealloc {[self stopTimer];self.scrollView.delegate nil;
}// 重新此方法是为了解决当cell超出UIScrollView时不能点击的问题
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {if ([self pointInside:point withEvent:event]) {// 判断点击的点是否在cell上for (UIView *cell in self.scrollView.subviews) {// 将cell的frame转换到当前视图上CGRect convertFrame CGRectZero;convertFrame.size cell.frame.size;convertFrame.origin.x cell.frame.origin.x self.scrollView.frame.origin.x - self.scrollView.contentOffset.x;convertFrame.origin.y self.scrollView.frame.origin.y cell.frame.origin.y;// 判断点击的点是否在cell上if (CGRectContainsPoint(convertFrame, point)) {// 修复cell上添加其他点击事件无效的bugUIView *view [super hitTest:point withEvent:event];if (view self || view cell || view self.scrollView) return cell;return view;}}// 判断点击的点是否在UIScrollView上CGPoint newPoint CGPointZero;newPoint.x point.x - self.scrollView.frame.origin.x self.scrollView.contentOffset.x;newPoint.y point.y - self.scrollView.frame.origin.y self.scrollView.contentOffset.y;if ([self.scrollView pointInside:newPoint withEvent:event]) {return [self.scrollView hitTest:newPoint withEvent:event];}// 系统处理return [super hitTest:point withEvent:event];}return nil;
}#pragma mark - Public Methods
- (void)reloadData {// 移除所有cell[self.scrollView.subviews makeObjectsPerformSelector:selector(removeFromSuperview)];// 停止定时器[self stopTimer];// 加载数据if (self.dataSource [self.dataSource respondsToSelector:selector(numberOfCellsInCycleScrollView:)]) {// 实际个数self.realCount [self.dataSource numberOfCellsInCycleScrollView:self];// 展示个数if (self.isInfiniteLoop) {self.showCount self.realCount 1 ? 1 : self.realCount * 3;}else {self.showCount self.realCount;}}// 清除原始数据[self.visibleCells removeAllObjects];[self.reusableCells removeAllObjects];self.visibleRange NSMakeRange(0, 0);//cell数量为1或defaultSelectIndex超过了当前数量if(self.defaultSelectIndex self.realCount) {self.defaultSelectIndex 0;}if(self.realCount 1) {self.timerIndex 0;}for (NSInteger i 0; i self.showCount; i){[self.visibleCells addObject:[NSNull null]];}__weak __typeof(self) weakSelf self;[self refreshSizeCompletion:^{[weakSelf initialScrollViewAndCellSize];}];
}- (void)refreshSizeCompletion:(void(^)(void))completion {if (self.bounds.size.width 0 || self.bounds.size.height 0) {[self layoutIfNeeded];// 此处做延时处理是为了解决使用Masonry布局时导致的view的大小不能及时更新的bugdispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.0f * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{if (self.bounds.size.width 0 || self.bounds.size.height 0) {[self refreshSizeCompletion:completion];}else {!completion ? : completion();}});}else {!completion ? : completion();}
}- (void)registerClass:(nonnull Class)cellClass forViewReuseIdentifier:(NSString *)identifier
{[self.viewClsDict setObject:NSStringFromClass(cellClass) forKey:identifier];
}- (__kindof LBMiddleExpandLoopViewBaseCell *)dequeueReusableCellWithIdentifier:(NSString *)identifier
{LBMiddleExpandLoopViewBaseCell *cell;for (LBMiddleExpandLoopViewBaseCell *cellReusable in self.reusableCells){if ([cellReusable.reuseIdentifier isEqualToString:identifier]) {cell cellReusable;}}if (!cell) {Class cellCls NSClassFromString(self.viewClsDict[identifier]);cell [[cellCls alloc] initWithReuseIdentifier:identifier];cell.userInteractionEnabled NO;} else {[self.reusableCells removeObject:cell];}return cell;
}- (void)scrollToCellAtIndex:(NSInteger)index animated:(BOOL)animated {if (index self.realCount) {[self stopTimer];if (self.isInfiniteLoop) {self.timerIndex self.realCount index;[NSObject cancelPreviousPerformRequestsWithTarget:self selector:selector(startTimer) object:nil];[self performSelector:selector(startTimer) withObject:nil afterDelay:0.5];} else {self.timerIndex index;}[self.scrollView setContentOffset:CGPointMake(self.cellSize.width * self.timerIndex, 0) animated:animated];[self setupCellsWithContentOffset:self.scrollView.contentOffset];[self updateVisibleCellAppearance];}
}- (void)adjustCurrentCell {if (self.isAutoScroll self.realCount 0) {self.scrollView.contentOffset CGPointMake(self.cellSize.width * self.timerIndex, 0);}
}- (void)startTimer {if (self.realCount 1 self.isAutoScroll) {[self stopTimer];// NSTimer *timer [NSTimer scheduledTimerWithTimeInterval:self.autoScrollTime target:self selector:selector(timerUpdate) userInfo:nil repeats:YES];
// [[NSRunLoop mainRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];// self.timer timer;}
}- (void)stopTimer {if (self.timer) {[self.timer invalidate];self.timer nil;}
}#pragma mark Private Methods
- (void)initialization {// 初始化默认数据self.clipsToBounds YES;self.isAutoScroll YES;self.isInfiniteLoop YES;self.minimumCellAlpha 1.0f;self.autoScrollTime 3.0f;// 添加scrollView[self addSubview:self.scrollView];
}- (void)initialScrollViewAndCellSize {self.originSize self.bounds.size;[self updateScrollViewAndCellSize];// 默认选中if (self.defaultSelectIndex 0 self.defaultSelectIndex self.realCount) {[self handleCellScrollWithIndex:self.defaultSelectIndex];}
}- (void)updateScrollViewAndCellSize {if (self.bounds.size.width 0 || self.bounds.size.height 0) return;// 设置cell尺寸self.cellSize CGSizeMake(self.bounds.size.width - 2 * self.leftRightMargin, self.bounds.size.height);if (self.delegate [self.delegate respondsToSelector:selector(sizeForCellInCycleScrollView:)]) {self.cellSize [self.delegate sizeForCellInCycleScrollView:self];}// 设置scrollView大小self.scrollView.frame CGRectMake(0, 0, self.cellSize.width, self.cellSize.height);self.scrollView.contentSize CGSizeMake(self.cellSize.width * self.showCount,0);self.scrollView.center CGPointMake(CGRectGetMidX(self.bounds), CGRectGetMidY(self.bounds));if (self.realCount 1) {CGPoint offset CGPointZero;if (self.isInfiniteLoop) { // 开启无限轮播// 滚动到第二组offset CGPointMake(self.cellSize.width * (self.realCount self.defaultSelectIndex), 0);self.timerIndex self.realCount self.defaultSelectIndex;}else {offset CGPointMake(self.cellSize.width * self.defaultSelectIndex, 0);self.timerIndex self.defaultSelectIndex;}[self.scrollView setContentOffset:offset animated:NO];// 自动轮播if (self.isAutoScroll) {[self startTimer];}}// 根据当前scrollView的offset设置显示的cell[self setupCellsWithContentOffset:self.scrollView.contentOffset];// 更新可见cell的显示[self updateVisibleCellAppearance];
}- (void)setupCellsWithContentOffset:(CGPoint)offset {if (self.showCount 0) return;if (self.cellSize.width 0 || self.cellSize.height 0) return;//计算_visibleRangeCGFloat originX self.scrollView.frame.origin.x 0 ? 0.01 : self.scrollView.frame.origin.x;CGFloat originY self.scrollView.frame.origin.y 0 ? 0.01 : self.scrollView.frame.origin.y;CGPoint startPoint CGPointMake(offset.x - originX, offset.y - originY);CGPoint endPoint CGPointMake(offset.x self.scrollView.frame.size.width originX, offset.y self.scrollView.frame.size.height originY);NSInteger startIndex 0;for (NSInteger i 0; i self.visibleCells.count; i) {if (self.cellSize.width * (i 1) startPoint.x) {startIndex i;break;}}NSInteger endIndex startIndex;for (NSInteger i self.visibleCells.count - 1; i startIndex; i --) {if (self.cellSize.width * i endPoint.x) {endIndex i;break;}}// 可见页分别向前向后扩展一个提高效率startIndex MAX(startIndex, 0);endIndex MIN(endIndex, self.visibleCells.count - 1);self.visibleRange NSMakeRange(startIndex, endIndex - startIndex 1);for (NSInteger i startIndex; i endIndex; i) {[self addCellAtIndex:i];}for (NSInteger i 0; i startIndex; i ) {[self removeCellAtIndex:i];}for (NSInteger i endIndex 1; i self.visibleCells.count; i ) {[self removeCellAtIndex:i];}
}- (void)updateVisibleCellAppearance {if (self.showCount 0) return;if (self.cellSize.width 0 || self.cellSize.height 0) return;CGFloat offsetX self.scrollView.contentOffset.x;for (NSInteger i self.visibleRange.location; i NSMaxRange(self.visibleRange); i) {LBMiddleExpandLoopViewBaseCell *cell self.visibleCells[i];CGFloat originX cell.frame.origin.x;CGFloat delta fabs(originX - offsetX);CGRect originCellFrame (CGRect){{self.cellSize.width * i, 0}, self.cellSize};CGFloat leftRightInset 0;CGFloat topBottomInset 0;CGFloat alpha 0;if (delta self.cellSize.width) {alpha (delta / self.cellSize.width) * self.minimumCellAlpha;CGFloat adjustLeftRightMargin self.leftRightMargin 0 ? 0 : self.leftRightMargin 1;CGFloat adjustTopBottomMargin self.topBottomMargin 0 ? 0 : self.topBottomMargin;leftRightInset adjustLeftRightMargin * delta / self.cellSize.width;topBottomInset adjustTopBottomMargin * delta / self.cellSize.width;NSInteger index self.realCount 0 ? 0 : i % self.realCount;if (index self.currentSelectIndex) {[self.scrollView bringSubviewToFront:cell];}} else {alpha self.minimumCellAlpha;leftRightInset self.leftRightMargin;topBottomInset self.topBottomMargin;[self.scrollView sendSubviewToBack:cell];}if (self.leftRightMargin 0 self.topBottomMargin 0) {cell.frame originCellFrame;}else {CGFloat scaleX (self.cellSize.width - leftRightInset * 2) / self.cellSize.width;CGFloat scaleY (self.cellSize.height - topBottomInset * 2) / self.cellSize.height;UIEdgeInsets insets UIEdgeInsetsMake(topBottomInset, leftRightInset - 0.1, topBottomInset, leftRightInset);cell.layer.transform CATransform3DMakeScale(scaleX, scaleY, 1.0);cell.frame UIEdgeInsetsInsetRect(originCellFrame, insets);}// 获取当前cellif (cell.tag self.currentSelectIndex) {self.currentCell cell;}}
}- (void)addCellAtIndex:(NSInteger)index {NSParameterAssert(index 0 index self.visibleCells.count);LBMiddleExpandLoopViewBaseCell *cell self.visibleCells[index];if ((NSObject *)cell [NSNull null]) {cell [self.dataSource cycleScrollView:self cellForViewAtIndex:index % self.realCount];if (cell) {[self.visibleCells replaceObjectAtIndex:index withObject:cell];cell.tag index % self.realCount;__weak __typeof(self) weakSelf self;cell.didCellClick ^(NSInteger index) {[weakSelf handleCellSelectWithIndex:index];};cell.frame CGRectMake(self.cellSize.width * index, 0, self.cellSize.width, self.cellSize.height);if (!cell.superview) {[self.scrollView addSubview:cell];}}}
}- (void)removeCellAtIndex:(NSInteger)index{LBMiddleExpandLoopViewBaseCell *cell [self.visibleCells objectAtIndex:index];if ((NSObject *)cell [NSNull null]) return;[self.reusableCells addObject:cell];if (cell.superview) {[cell removeFromSuperview];}[self.visibleCells replaceObjectAtIndex:index withObject:[NSNull null]];
}- (void)handleCellSelectWithIndex:(NSInteger)index {if ([self.delegate respondsToSelector:selector(cycleScrollView:didSelectCellAtIndex:)]) {[self.delegate cycleScrollView:self didSelectCellAtIndex:index];}
}- (void)handleCellScrollWithIndex:(NSInteger)index {self.currentSelectIndex index;// 获取当前cellfor (NSInteger i self.visibleRange.location; i NSMaxRange(self.visibleRange); i) {LBMiddleExpandLoopViewBaseCell *cell self.visibleCells[i];if (cell.tag index) {self.currentCell cell;}}if ([self.delegate respondsToSelector:selector(cycleScrollView:didScrollCellToIndex:)]) {[self.delegate cycleScrollView:self didScrollCellToIndex:index];}
}- (void)timerUpdate {self.timerIndex;// bug fixed解决反向滑动停止后可能出现的自动滚动错乱问题if (self.timerIndex self.realCount * 2) {self.timerIndex self.realCount * 2;}if (!self.isInfiniteLoop) {if (self.timerIndex self.realCount) {self.timerIndex 0;}}[self.scrollView setContentOffset:CGPointMake(self.cellSize.width * self.timerIndex, 0) animated:YES];
}#pragma mark UIScrollView Delegate
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{if (self.realCount 0) return;if (self.cellSize.width 0 || self.cellSize.height 0) return;NSInteger index 0;index (NSInteger)round(self.scrollView.contentOffset.x / self.cellSize.width) % self.realCount;if (self.isInfiniteLoop) {if (self.realCount 1) {CGFloat horIndex scrollView.contentOffset.x / self.cellSize.width;if (horIndex 2 * self.realCount) {scrollView.contentOffset CGPointMake(self.cellSize.width * self.realCount, 0);self.timerIndex self.realCount;}if (horIndex (self.realCount - 1)) {scrollView.contentOffset CGPointMake(self.cellSize.width * (2 * self.realCount - 1), 0);self.timerIndex 2 * self.realCount - 1;}}}else {index 0;}[self setupCellsWithContentOffset:scrollView.contentOffset];[self updateVisibleCellAppearance];if (index 0 self.currentSelectIndex ! index) {[self handleCellScrollWithIndex:index];}[self handleScrollViewDidScroll:scrollView];
}- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {[self stopTimer];if ([self.delegate respondsToSelector:selector(cycleScrollView:willBeginDragging:)]) {[self.delegate cycleScrollView:self willBeginDragging:scrollView];}
}// 结束拖拽时调用decelerate是否有减速
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {if (!decelerate) {[self startTimer];}if ([self.delegate respondsToSelector:selector(cycleScrollView:didEndDragging:willDecelerate:)]) {[self.delegate cycleScrollView:self didEndDragging:scrollView willDecelerate:decelerate];}
}// 结束减速是调用
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {[self startTimer];if ([self.delegate respondsToSelector:selector(cycleScrollView:didEndDecelerating:)]) {[self.delegate cycleScrollView:self didEndDecelerating:scrollView];}
}- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {if (self.realCount 1 self.isAutoScroll) {NSInteger index round(targetContentOffset-x / self.cellSize.width);self.timerIndex index;}
}- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {[self updateVisibleCellAppearance];if ([self.delegate respondsToSelector:selector(cycleScrollView:didEndScrollingAnimation:)]) {[self.delegate cycleScrollView:self didEndScrollingAnimation:scrollView];}
}- (void)handleScrollViewDidScroll:(UIScrollView *)scrollView {if ([self.delegate respondsToSelector:selector(cycleScrollView:didScroll:)]) {[self.delegate cycleScrollView:self didScroll:scrollView];}if ([self.delegate respondsToSelector:selector(cycleScrollView:scrollingFromIndex:toIndex:ratio:)]) {BOOL isFirstRevirse NO; // 是否在第一个位置反向滑动CGFloat ratio 0; // 滑动百分比CGFloat offsetX scrollView.contentOffset.x;CGFloat maxW self.realCount * scrollView.bounds.size.width;CGFloat changeOffsetX self.isInfiniteLoop ? (offsetX - maxW) : offsetX;if (changeOffsetX 0) {changeOffsetX -changeOffsetX;isFirstRevirse YES;}ratio (changeOffsetX / scrollView.bounds.size.width);if (ratio self.realCount || ratio 0) return; // 越界不作处理ratio MAX(0, MIN(self.realCount, ratio));NSInteger baseIndex floor(ratio);if (baseIndex 1 self.realCount) {// 右边越界了baseIndex 0;}CGFloat remainderRatio ratio - baseIndex;if (remainderRatio 0 || remainderRatio 1) return;NSInteger toIndex 0;if (isFirstRevirse) {baseIndex self.realCount - 1;toIndex 0;remainderRatio 1 - remainderRatio;}else if (baseIndex self.realCount - 1) {toIndex 0;}else {toIndex baseIndex 1;}[self.delegate cycleScrollView:self scrollingFromIndex:baseIndex toIndex:toIndex ratio:remainderRatio];}
}#pragma mark - 懒加载
- (UIScrollView *)scrollView {if (!_scrollView) {_scrollView [[UIScrollView alloc] initWithFrame:self.bounds];_scrollView.scrollsToTop NO;_scrollView.delegate self;_scrollView.pagingEnabled YES;_scrollView.clipsToBounds NO;_scrollView.showsHorizontalScrollIndicator NO;_scrollView.showsVerticalScrollIndicator NO;}return _scrollView;
}- (NSMutableArray *)visibleCells {if (!_visibleCells) {_visibleCells [NSMutableArray new];}return _visibleCells;
}- (NSMutableDictionary *)viewClsDict
{if (!_viewClsDict) {_viewClsDict [NSMutableDictionary dictionary];}return _viewClsDict;
}- (NSMutableArray *)reusableCells {if (!_reusableCells) {_reusableCells [NSMutableArray new];}return _reusableCells;
}end
