oc版本为啥不用nstimer，而用performSelector

[jeffshi]

performSelector会在页面被销毁的时候继续执行导致crash

[jeffshi]

//
// CWCarousel.m
// CWCarousel
//
// Created by WangChen on 2018/4/3.
// Copyright © 2018年 ChenWang. All rights reserved.
//

#import "CWCarousel.h"

@interface CWTempleteCell: UICollectionViewCell
@EnD

@implementation CWTempleteCell
@EnD

@interface CWCarousel ()<UICollectionViewDelegate, UICollectionViewDataSource> {

}
@Property (nonatomic, strong) UICollectionView carouselView;
@Property (nonatomic, assign) NSInteger numbers;
@Property (nonatomic, assign) NSInteger currentIndex;
@Property (nonatomic, assign) NSInteger infactIndex;
@Property (nonatomic, assign) CGFloat addHeight;
/*
自动播放是否暂停
*/
@Property (nonatomic, assign) BOOL isPause;

/**
当前展示在中间的cell下标
*/
@Property (nonatomic, strong) NSIndexPath *currentIndexPath;

@EnD
@implementation CWCarousel
@synthesize carouselView = _carouselView;

• (instancetype)initWithFrame:(CGRect)frame delegate:(id)delegate datasource:(id)datasource flowLayout:(CWFlowLayout )flowLayout {
  CGFloat addHeight = 0;
  // if(flowLayout.style == CWCarouselStyle_H_3) {
  // / 如果是CWCarouselStyle_H_3, 因为中间一张图片放大的原因,需要扩充一下frame的高度,所以会和实际的传入的frame
  // 的高度有部分偏差
  // */
  // addHeight = (flowLayout.maxScale - 1) * CGRectGetHeight(frame);
  // }
  frame.size.height += addHeight;
  self.addHeight = addHeight;
  if(self = [super initWithFrame:frame]) {
  _flowLayout = flowLayout;
  self.delegate = delegate;
  self.datasource = datasource;
  self.isAuto = NO;
  self.autoTimInterval = 3;
  self.endless = YES;
  [self configureView];
  }
  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(appBecomeInactive:) name:UIApplicationWillResignActiveNotification object:nil];
  [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(appBecomeActive:) name:UIApplicationDidBecomeActiveNotification object:nil];
  return self;
  }

• (void)appBecomeInactive:(NSNotification *)notification {
  [self adjustErrorCell:YES];
  }

• (void)appBecomeActive:(NSNotification *)notification {
  [self adjustErrorCell:YES];
  }

• (void)controllerWillAppear {
  if(self.isAuto) {
  [self resumePlay];
  }
  [self adjustErrorCell:YES];
  }

• (void)controllerWillDisAppear {
  if(self.isAuto) {
  [self pause];
  }
  [self adjustErrorCell:YES];
  }

• (void)dealloc {

  [self destoryTimer];
  [[NSNotificationCenter defaultCenter] removeObserver:self];
  }

• (void)willMoveToSuperview:(UIView *)newSuperview {
  newSuperview.clipsToBounds = NO;
  if(self.customPageControl == nil && self.pageControl.superview == nil) {
  [self addSubview:self.pageControl];
  self.pageControl.translatesAutoresizingMaskIntoConstraints = NO;
  [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[control]-0-|"
  options:kNilOptions
  metrics:nil
  views:@{@"control" : self.pageControl}]];
  [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[control(30)]-0-|"
  options:kNilOptions
  metrics:nil
  views:@{@"control" : self.pageControl}]];
  }else if(self.customPageControl || self.customPageControl.superview == nil) {
  [self addSubview:self.customPageControl];
  }
  [super willMoveToSuperview:newSuperview];
  }

• (void)registerViewClass:(Class)viewClass identifier:(NSString *)identifier {
  [self.carouselView registerClass:viewClass forCellWithReuseIdentifier:identifier];
  }

• (void)registerNibView:(NSString *)nibName identifier:(NSString *)identifier {
  [self.carouselView registerNib:[UINib nibWithNibName:nibName bundle:[NSBundle mainBundle]]
  forCellWithReuseIdentifier:identifier];
  }

• (void)freshCarousel {
  if([self numbers] <= 0) {
  return;
  }
  [self.carouselView reloadData];
  [self.carouselView layoutIfNeeded];
  if (self.endless)
  [self.carouselView scrollToItemAtIndexPath:[self originIndexPath] atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:NO];
  else
  {
  if(self.flowLayout.style == CWCarouselStyle_Normal)
  {
  [self.carouselView scrollToItemAtIndexPath:self.currentIndexPath = [NSIndexPath indexPathForRow:0 inSection:0] atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:NO];
  }
  else
  {
  [self.carouselView scrollToItemAtIndexPath:self.currentIndexPath = [NSIndexPath indexPathForRow:1 inSection:0] atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:NO];
  }
  }

  self.carouselView.userInteractionEnabled = YES;
  if (self.isAuto) {
  [self play];
  }
  }
  #pragma mark - < Scroll Delegate >
  /// 开始拖拽

• (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {
  // 防止拖动加速度太大,一次跳过多张图片,这里设置一下
  if (@available(iOS 14.0, *)) {
  scrollView.pagingEnabled = NO;
  } else {
  scrollView.pagingEnabled = YES;
  }
  if (self.isAuto) {
  [self stop];
  }
  if (self.delegate && [self.delegate respondsToSelector:@selector(CWCarousel:didStartScrollAtIndex:indexPathRow:)]) {
  [self.delegate CWCarousel:self didStartScrollAtIndex:[self caculateIndex:self.currentIndexPath.row] indexPathRow:self.currentIndexPath.row];
  }
  }

/// 将要结束拖拽

• (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset {
  if (!self.endless)
  {
  NSInteger maxIndex = [self numbers] - 1;
  NSInteger minIndex = 0;
  if(self.flowLayout.style != CWCarouselStyle_Normal)
  {
  maxIndex = [self infactNumbers] - 2;
  minIndex = 1;
  }
  if (velocity.x == 0) {
  //还有一种情况,当滑动后手指按住不放,然后松开,此时的加速度其实是为0的
  [self adjustErrorCell:NO];
  if (@available(iOS 14.0, *)) {
  // iOS14以前,就算加速度为0,后续系统会还是会走scrollViewWillBeginDecelerating:回调
  // 但是iOS14以后,加速度为0时,不会在后续执行回调.这里手动触发一下
  [self scrollViewWillBeginDecelerating:self.carouselView];
  }
  return;
  }
  if (velocity.x >= 0 && self.currentIndexPath.row == maxIndex)
  {
  return;
  }
  if (velocity.x <= 0 && self.currentIndexPath.row == minIndex)
  {
  return;
  }
  }

  if(velocity.x > 0) {
  //左滑,下一张
  self.currentIndexPath = [NSIndexPath indexPathForRow:self.currentIndexPath.row + 1 inSection:self.currentIndexPath.section];
  }else if (velocity.x < 0) {
  //右滑,上一张
  self.currentIndexPath = [NSIndexPath indexPathForRow:self.currentIndexPath.row - 1 inSection:self.currentIndexPath.section];
  }else if (velocity.x == 0) {
  //还有一种情况,当滑动后手指按住不放,然后松开,此时的加速度其实是为0的
  [self adjustErrorCell:NO];
  if (@available(iOS 14.0, *)) {
  // iOS14以前,就算加速度为0,后续系统会还是会走scrollViewWillBeginDecelerating:回调
  // 但是iOS14以后,加速度为0时,不会在后续执行回调.这里手动触发一下
  [self scrollViewWillBeginDecelerating:self.carouselView];
  }
  }
  }

/// 开始减速

• (void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView {

  if(self.currentIndexPath != nil &&
  self.currentIndexPath.row < [self infactNumbers] &&
  self.currentIndexPath.row >= 0) {
  // 中间一张轮播,居中显示
  if (!self.endless)
  {
  if (self.currentIndexPath.row == 0 && self.style != CWCarouselStyle_Normal)
  {
  self.currentIndexPath = [NSIndexPath indexPathForRow:1 inSection:self.currentIndexPath.section];
  }
  else if (self.currentIndexPath.row == [self infactNumbers] - 1 && self.style != CWCarouselStyle_Normal)
  {
  self.currentIndexPath = [NSIndexPath indexPathForRow:[self infactNumbers] - 2 inSection:self.currentIndexPath.section];
  }
  }
  [self.carouselView scrollToItemAtIndexPath:self.currentIndexPath atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:YES];
  }
  }

/// 减速完成

• (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {

  // 打开交互
  scrollView.pagingEnabled = NO;
  if(self.isAuto) {
  [self play];
  }
  }

/// 滚动动画完成

• (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView {

  // 滚动完成,打开交互,关掉pagingEnabled
  // 为什么要关掉pagingEnabled呢,因为切换控制器的时候会有系统级bug,不信你试试.
  scrollView.userInteractionEnabled = YES;
  scrollView.pagingEnabled = NO;
  if(self.isAuto) {
  [self play];
  }
  if (self.endless)
  [self checkOutofBounds];

// if(!self.endless)
// {
// CGFloat space = self.flowLayout.itemSpace_H + self.flowLayout.itemWidth * (1 - self.flowLayout.minScale) * 0.5;
// if(self.currentIndexPath.row == 0)
// self.carouselView.contentInset = UIEdgeInsetsMake(0, space, 0, 0);
// else if(self.currentIndexPath.row == [self numbers] - 1)
// self.carouselView.contentInset = UIEdgeInsetsMake(0, 0, 0, space);
// else
// self.carouselView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0);
// }

if (self.delegate && [self.delegate respondsToSelector:@selector(CWCarousel:didEndScrollAtIndex:indexPathRow:)]) {
    [self.delegate CWCarousel:self didEndScrollAtIndex:[self caculateIndex:self.currentIndexPath.row] indexPathRow:self.currentIndexPath.row];
}

}

// 滚动中

• (void)scrollViewDidScroll:(UIScrollView *)scrollView {
  // 滚动过程中关闭交互
  // scrollView.userInteractionEnabled = NO;
  }
  #pragma mark - < Logic Helper >

• (NSIndexPath *)originIndexPath {

  NSInteger num = [self numbers];
  if (num <= 0) {
  return [[NSIndexPath alloc] initWithIndex:0];
  }

  NSInteger centerIndex = [self infactNumbers] / [self numbers];

  if (self.endless) {
  if(centerIndex <= 1) {
  if (centerIndex == 1) {
  self.currentIndexPath = [NSIndexPath indexPathForRow:0 inSection:0];
  }else {
  self.currentIndexPath = [NSIndexPath indexPathForRow:self.numbers inSection:0];
  }
  }else {
  self.currentIndexPath = [NSIndexPath indexPathForRow:centerIndex / 2 * [self numbers] inSection:0];
  }
  }else {
  NSInteger row = self.flowLayout.style == CWCarouselStyle_Normal ? 0 : 1;
  self.currentIndexPath = [NSIndexPath indexPathForRow:row inSection:0];
  }

  return self.currentIndexPath;
  }

• (void)checkOutofBounds {
  if ([self numbers] <= 0) {return;}
  // 越界检查
  if(self.currentIndexPath.row == [self infactNumbers] - 1) {
  //最后一张
  NSIndexPath *origin = [self originIndexPath];
  NSInteger index = [self caculateIndex:self.currentIndexPath.row] - 1;
  self.currentIndexPath = [NSIndexPath indexPathForRow:origin.row + index inSection:origin.section];
  [self.carouselView scrollToItemAtIndexPath:self.currentIndexPath atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:NO];
  self.carouselView.userInteractionEnabled = YES;
  }else if(self.currentIndexPath.row == 0) {
  //第一张
  NSIndexPath *origin = [self originIndexPath];
  NSInteger index = [self caculateIndex:self.currentIndexPath.row];
  self.currentIndexPath = [NSIndexPath indexPathForRow:origin.row + index inSection:origin.section];
  [self.carouselView scrollToItemAtIndexPath:self.currentIndexPath atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:NO];
  self.carouselView.userInteractionEnabled = YES;
  }
  }

• (void)pageControlClick:(UIPageControl *)sender {
  if (![sender isKindOfClass:[UIPageControl class]]) {
  return;
  }
  NSInteger page = sender.currentPage;
  NSInteger prePage = [self caculateIndex:self.currentIndexPath.row];
  if(page == prePage) {
  return;
  }
  NSIndexPath *indexPath = nil;
  if(prePage - page == [self numbers] - 1) {
  //最后一张跳到第一张
  indexPath = [NSIndexPath indexPathForRow:self.currentIndexPath.row + 1 inSection:0];
  }else if(page - prePage == [self numbers] - 1) {
  //第一张跳到最后一张
  indexPath = [NSIndexPath indexPathForRow:self.currentIndexPath.row - 1 inSection:0];
  }else {
  indexPath = [NSIndexPath indexPathForRow:self.currentIndexPath.row + page - prePage inSection:0];
  }
  [self.carouselView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:YES];
  self.currentIndexPath = indexPath;
  }

/**
实际下标转换成业务需求下标

@param factIndex 实际下标
@return 业务需求下标
*/

• (NSInteger)caculateIndex:(NSInteger)factIndex {
  if (self.numbers <= 0) {
  return 0;
  }
  NSInteger row = factIndex % [self numbers];
  if(!self.endless && self.flowLayout.style != CWCarouselStyle_Normal)
  {
  row = factIndex % [self infactNumbers] - 1;
  }
  return row;
  }

• (void)adjustErrorCell:(BOOL)isScroll {
  NSArray <NSIndexPath *> *indexPaths = [self.carouselView indexPathsForVisibleItems];
  NSMutableArray <UICollectionViewLayoutAttributes *> *attriArr = [NSMutableArray arrayWithCapacity:indexPaths.count];
  [indexPaths enumerateObjectsUsingBlock:^(NSIndexPath * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
  UICollectionViewLayoutAttributes *attri = [self.carouselView layoutAttributesForItemAtIndexPath:obj];
  [attriArr addObject:attri];
  }];
  CGFloat centerX = self.carouselView.contentOffset.x + CGRectGetWidth(self.carouselView.frame) * 0.5;
  __block CGFloat minSpace = MAXFLOAT;
  // BOOL shouldSet = YES;
  // if (self.flowLayout.style != CWCarouselStyle_Normal && indexPaths.count <= 2)
  // {
  // shouldSet = NO;
  // }
  [attriArr enumerateObjectsUsingBlock:^(UICollectionViewLayoutAttributes * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
  obj.zIndex = 0;
  // if(ABS(minSpace) > ABS(obj.center.x - centerX) && shouldSet) {
  // minSpace = obj.center.x - centerX;
  // self.currentIndexPath = obj.indexPath;
  // }
  if(ABS(minSpace) > ABS(obj.center.x - centerX)) {
  minSpace = obj.center.x - centerX;
  self.currentIndexPath = obj.indexPath;
  }
  }];
  if(isScroll) {
  [self scrollViewWillBeginDecelerating:self.carouselView];
  }
  }

• (void)play {
  [self stop];
  if(self.isPause) {
  return;
  }
  [self showTimer];
  // [self performSelector:@selector(nextCell) withObject:nil afterDelay:self.autoTimInterval];
  }

• (void)showTimer
  {
  if (!_timer) {
  //开始倒计时
  WS(weakSelf)
  _timer = [NSTimer bk_scheduledTimerWithTimeInterval:self.autoTimInterval block:^(NSTimer *timer) {
  [weakSelf nextCell];
  } repeats:YES];
  // [_timer setFireDate:[NSDate date]];
  //不受滚动事件影响
  [[NSRunLoop mainRunLoop] addTimer:_timer forMode:NSRunLoopCommonModes];
  } else {
  [_timer setFireDate:[NSDate dateWithTimeInterval:self.autoTimInterval sinceDate:[NSDate date]]];
  }
  }

-(void)destoryTimer
{
if (_timer) {
[_timer invalidate];
_timer = nil;
}
}

• (void)nextCell {
  if([self numbers] <= 0) {
  return;
  }
  NSInteger maxIndex = 1;
  if(!self.endless && self.flowLayout.style != CWCarouselStyle_Normal)
  {
  maxIndex = 2;
  }
  if(self.currentIndexPath.row < [self infactNumbers] - maxIndex)
  {
  NSIndexPath *indexPath = [NSIndexPath indexPathForRow:self.currentIndexPath.row + 1 inSection:self.currentIndexPath.section];
  [self.carouselView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:YES];
  self.currentIndexPath = indexPath;
  }
  else if(!self.endless)
  {
  NSIndexPath *indexPath = [NSIndexPath indexPathForRow:maxIndex - 1 inSection:self.currentIndexPath.section];
  [self.carouselView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredHorizontally animated:YES];
  self.currentIndexPath = indexPath;
  }
  // [self performSelector:@selector(nextCell) withObject:nil afterDelay:self.autoTimInterval];
  }

• (void)stop {
  if (_timer) {
  [_timer setFireDate:[NSDate distantFuture]];
  }
  // [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(nextCell) object:nil];
  // [NSObject cancelPreviousPerformRequestsWithTarget:self];
  }

• (void)resumePlay {
  self.isPause = NO;
  [self play];
  }

• (void)pause {
  self.isPause = YES;
  [self stop];
  }

• (void)releaseTimer {
  [self stop];
  }

#pragma mark - < Configure View>

• (void)configureView {
  self.backgroundColor = [UIColor blackColor];
  self.carouselView.showsVerticalScrollIndicator = NO;
  self.carouselView.showsHorizontalScrollIndicator = NO;
  self.carouselView.decelerationRate = 0;
  }

#pragma mark - < Delegate, Datasource >

• (nonnull __kindof UICollectionViewCell *)collectionView:(nonnull UICollectionView *)collectionView cellForItemAtIndexPath:(nonnull NSIndexPath *)indexPath {
  if(!self.endless
  && self.flowLayout.style != CWCarouselStyle_Normal
  && (indexPath.row == 0 || indexPath.row == [self infactNumbers] - 1))
  {
  // 添加占位cell
  UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"tempCell" forIndexPath:indexPath];
  cell.contentView.backgroundColor = [UIColor clearColor];
  return cell;
  }
  else
  {
  if(self.datasource &&
  [self.datasource respondsToSelector:@selector(viewForCarousel:indexPath:index:)])
  {
  UICollectionViewCell *cell = [self.datasource viewForCarousel:self indexPath:indexPath index:[self caculateIndex:indexPath.row]];
  return cell;
  }
  return nil;
  }
  }

• (NSInteger)collectionView:(nonnull UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
  if([self numbers] > 0)
  return [self infactNumbers];
  else
  return 0;
  }

• (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
  if(self.delegate &&
  [self.delegate respondsToSelector:@selector(CWCarousel:didSelectedAtIndex:)]) {
  [self.delegate CWCarousel:self didSelectedAtIndex:[self caculateIndex:indexPath.row]];
  }
  // 处于动画中时,点击cell,可能会出现cell不居中问题.这里处理下
  // 将里中心点最近的那个cell居中
  [self adjustErrorCell:YES];
  }

#pragma mark -

• (void)setBackgroundColor:(UIColor *)backgroundColor {
  self.carouselView.backgroundColor = backgroundColor;
  [super setBackgroundColor:backgroundColor];
  }

• (void)setCurrentIndexPath:(NSIndexPath *)currentIndexPath {
  _currentIndexPath = currentIndexPath;
  if(self.customPageControl == nil)
  self.pageControl.currentPage = [self caculateIndex:currentIndexPath.row];
  else
  self.customPageControl.currentPage = [self caculateIndex:currentIndexPath.row];
  }

• (void)setEndless:(BOOL)endless {
  if(_endless != endless)
  {
  _endless = endless;
  }
  }

#pragma mark - < getter >

• (UICollectionView *)carouselView {
  if(!_carouselView) {
  // self.carouselView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, self.addHeight * 0.5, self.frame.size.width, self.frame.size.height - self.addHeight) collectionViewLayout:self.flowLayout];
  self.carouselView = [[UICollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:self.flowLayout];
  _carouselView.clipsToBounds = NO;
  _carouselView.delegate = self;
  _carouselView.dataSource = self;
  _carouselView.translatesAutoresizingMaskIntoConstraints = NO;
  [_carouselView registerClass:[CWTempleteCell class] forCellWithReuseIdentifier:@"tempCell"];
  [self addSubview:_carouselView];

    NSDictionary *views = @{@"view" : self.carouselView};
    NSDictionary *margins = @{@"top" : @(self.addHeight * 0.5),
                              @"bottom" : @(self.addHeight * 0.5)
                              };
    NSString *str = @"H:|-0-[view]-0-|";
    [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:str
                                                                 options:kNilOptions
                                                                 metrics:margins
                                                                   views:views]];
    str = @"V:|-top-[view]-top-|";
    [self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:str
                                                                 options:kNilOptions
                                                                 metrics:margins
                                                                   views:views]];
  

  }
  return _carouselView;
  }

• (CWCarouselStyle)style {
  if(self.flowLayout)
  {
  return self.flowLayout.style;
  }
  return CWCarouselStyle_Unknow;
  }

/**
Description

@return 业务需求需要展示轮播图个数
*/

• (NSInteger)numbers {
  if(self.datasource &&
  [self.datasource respondsToSelector:@selector(numbersForCarousel)]) {
  self.pageControl.numberOfPages = [self.datasource numbersForCarousel];
  return self.pageControl.numberOfPages;
  }
  return 0;
  }

/**
轮播图实际加载视图个数

@return 轮播图实际加载视图个数
*/

• (NSInteger)infactNumbers {

  NSInteger num = [self numbers];

  if ( 0 >= num) {
  return 0;
  }

  [self.carouselView setScrollEnabled:YES];

  if (self.endless)
  {
  if (num < 1) {
  [self.carouselView setScrollEnabled:NO];
  return num;
  }
  // 如果是无限轮播,默认加载300个
  return 300;
  }
  else
  {
  // 如果不是无限轮播,出了第一种样式,其他的样式要加2个占位空cell
  if(self.flowLayout.style == CWCarouselStyle_Normal)
  {
  return [self numbers];
  }
  else
  {
  if (num == 1) {
  [self.carouselView setScrollEnabled:NO];
  }
  // 前后2个占位cell,所以+2
  return [self numbers] + 2;
  }
  }
  }

• (UIPageControl *)pageControl {
  if(!_pageControl) {
  self.pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(0, 0, 300, 30)];
  CGPoint center = self.center;
  center.y = CGRectGetHeight(self.frame) - 30 * 0.5;
  _pageControl.pageIndicatorTintColor = [UIColor blackColor];
  _pageControl.currentPageIndicatorTintColor = [UIColor whiteColor];
  _pageControl.userInteractionEnabled = NO;
  [_pageControl addTarget:self action:@selector(pageControlClick:) forControlEvents:UIControlEventTouchUpInside];
  _pageControl.center = center;
  }
  return _pageControl;
  }

• (NSString *)version {
  return @"1.1.7";
  }

#pragma mark - Setter

• (void)setCustomPageControl:(UIView *)customPageControl {
  _customPageControl = customPageControl;
  if(_customPageControl && _customPageControl.superview == nil)
  {
  [self addSubview:_customPageControl];
  [self bringSubviewToFront:_customPageControl];
  if(self.pageControl.superview == _customPageControl.superview)
  {
  [self.pageControl removeFromSuperview];
  }
  }
  }
  @EnD

[jeffshi]

@Property (nonatomic, weak) NSTimer *timer;这段代码加到.h文件
NSTimer用的是#import "NSTimer+BlocksKit.h"，和控制器解耦，避免内存泄漏

[baozoudiudiu]

不管是使用timer还是perform，都是要在对应的地方编写移除代码的。个人认为其实是没有太大差别的（当然timer功能上会更强大一些）。控件有对应的销毁方法暴露在.h文件中，你应该是没有调用而导致的。