150行程式碼搞定輪播圖
思路：底層scrollview contentsize為3個螢幕寬 新增三個圖片檢視0，1，2 初始便偏移到中間檢視1（中間一個圖片檢視，左右各一個） 左滑或者右滑結束 scrollview都滑回原來位置，且無動畫，重新整理的是圖片檢視圖片地址，也就是每滑動一下需要處理的是陣列元素的迴圈移動。通過重新整理圖片檢視的圖片地址達到圖片無線滾動的檢視效果，，同時新增計時器自動滾動，，滑動時計時器銷燬，，滑動結束計時器開啟（sdwebimage 載入圖片有快取機制，只要圖片地址沒變網路載入只走一次）
圖片個數無限制
借用SDCycleScrollView的圖片來用用
自動滾動：
手動滾動：
計時器停止和啟動
demo ：連結:https://pan.baidu.com/s/1wjgSHoO4V_OkIHC37RQyMw 密碼:60ah
建立UIview為 ScrollImageView
#import <UIImageView+WebCache.h>
@interface ScrollImageView()<UIScrollViewDelegate>
/// 底部滾動檢視
@property (nonatomic, strong) UIScrollView *backScrollView;
/// 判斷滾動方向
@property (nonatomic, assign) CGFloat contentOffsetX;
/// 圖片地址陣列
@property (nonatomic, strong) NSMutableArray *imageArr;
/// 點選連結地址陣列
@property (nonatomic, strong) NSMutableArray *imageUrlArr;
@property (nonatomic, strong) NSMutableArray *imageUrlsaveArr;
@property (nonatomic, strong) NSMutableArray *imagesaveArr;
@property (nonatomic, strong) NSMutableArray *imageViewArr;
@property (nonatomic, strong) NSMutableArray *tapGestureArr;
@property (nonatomic, strong) NSTimer *timer;
@end
@implementation ScrollImageView
- (instancetype)initWithFrame:(CGRect)frame{
self = [super initWithFrame:frame];
if (self) {
self.imageViewArr = [NSMutableArray array];
self.timer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(timeAction) userInfo:nil repeats:YES];
[self createView];
}
return self;
}
- (void)reloadScrollView:(NSMutableArray *)imageArr urlArr:(NSMutableArray *)urlArr{
self.imageArr = [NSMutableArray array];
self.imageUrlArr = [NSMutableArray array];
if (imageArr.count>0) {
if (imageArr.count == 1) {
for (NSInteger i =0; i<3; i++) {
[self.imageArr addObject:imageArr[0]];
[self.imageUrlArr addObject:urlArr[0]];
}
[self.timer invalidate];
self.timer = nil;
self.backScrollView.scrollEnabled = NO;
}else if (imageArr.count == 2){
for (NSInteger i = 0; i<4; i++) {
if (i<2) {
[self.imageArr addObject:imageArr[i]];
[self.imageUrlArr addObject:urlArr[i]];
}else{
[self.imageArr addObject:imageArr[i-2]];
[self.imageUrlArr addObject:urlArr[i-2]];
}
}
}else{
/// 對圖片陣列和點選連結地址處理 使第一張圖片顯示在三個圖片z檢視的中間位置
for (NSInteger i = 0; i<imageArr.count; i++) {
if (i == 0) {
[self.imageArr addObject:imageArr[imageArr.count-1]];
[self.imageUrlArr addObject:urlArr[urlArr.count-1]];
}else{
[self.imageArr addObject:imageArr[i-1]];
[self.imageUrlArr addObject:urlArr[i-1]];
}
}
}
/// 對圖片檢視陣列中的UIimageview設定圖片
for (NSInteger i = 0; i<3; i++) {
UIImageView *image = self.imageViewArr[i];
[image sd_setImageWithURL:[NSURL URLWithString:self.imageArr[i]]];
}
}else{
[self.timer invalidate];
self.timer = nil;
self.backScrollView.scrollEnabled = NO;
}
}
- (void)createView{
self.backScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
self.backScrollView.contentSize = CGSizeMake(self.frame.size.width*3, 0);
[self addSubview:self.backScrollView];
self.backScrollView.delegate = self;
self.backScrollView.pagingEnabled = YES;
self.backScrollView.showsHorizontalScrollIndicator = NO;
///固定只有三個圖片檢視
[self setScrollViewContentOffsetCenter];
for (NSInteger i = 0; i<3; i++) {
UIImageView *image = [[UIImageView alloc] initWithFrame:CGRectMake(i*self.frame.size.width, 0, self.frame.size.width, self.frame.size.height)];
image.userInteractionEnabled = YES;
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapAction:)];
[image addGestureRecognizer:tap];
image.tag = i;
[self.imageViewArr addObject:image];
[self.backScrollView addSubview:image];
}
}
//// 圖片的點選代理方法
- (void)tapAction:(UITapGestureRecognizer *)tap{
[self.delegate scrollImageViewTapAction:self.imageUrlArr[1]];
}
/// 偏移到中心位置
- (void)setScrollViewContentOffsetCenter {
[self.backScrollView setContentOffset:CGPointMake(self.frame.size.width, 0) animated:NO];
}
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
int contentOffsetX = scrollView.contentOffset.x;
/// 左滑
if(contentOffsetX >= (2 * self.frame.size.width)) {
[self.backScrollView setContentOffset:CGPointMake(self.frame.size.width, 0)];
[self reloadImage:1];
}
/// 右劃
if(contentOffsetX <= 0) {
[self.backScrollView setContentOffset:CGPointMake(self.frame.size.width, 0)];
[self reloadImage:0];
}
}
- ( void )scrollViewWillBeginDragging:( UIScrollView *)scrollView{
[self.timer invalidate];
self.timer = nil;
}
/// 手指已經離開螢幕
- ( void )scrollViewDidEndDragging:( UIScrollView *)scrollView willDecelerate:(BOOL )decelerate{
self.timer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(timeAction) userInfo:nil repeats:YES];
}
- (void)reloadImage:(NSInteger)type{
if (type == 0) {
/// 右劃 圖片陣列像右移動 第0個圖變成最後一個 第一個變成第0個 第二個變成第1個。。。。最後一個變成第0個
self.imagesaveArr = [NSMutableArray arrayWithArray:self.imageArr];
self.imageUrlsaveArr = [NSMutableArray arrayWithArray:self.imageUrlArr];
self.imageArr = [NSMutableArray array];
self.imageUrlArr = [NSMutableArray array];
for (NSInteger i = 0; i<self.imagesaveArr.count; i++) {
if (i == 0) {
[self.imageArr addObject:self.imagesaveArr[self.imagesaveArr.count - 1]];
[self.imageUrlArr addObject:self.imageUrlsaveArr[self.imageUrlsaveArr.count - 1]];
}else{
[self.imageArr addObject:self.imagesaveArr[i-1]];
[self.imageUrlArr addObject:self.imageUrlsaveArr[i-1]];
}
}
for (NSInteger i = 0; i<self.imageViewArr.count; i++) {
UIImageView *image = self.imageViewArr[i];
[image sd_setImageWithURL:[NSURL URLWithString:self.imageArr[i]]];
}
}else{
/// 左滑 圖片陣列像左移動 第0個圖變成第一個 第一個變成第2個 第二個變成第3個。。.。最後一個變成第0個
self.imagesaveArr = [NSMutableArray arrayWithArray:self.imageArr];
self.imageUrlsaveArr = [NSMutableArray arrayWithArray:self.imageUrlArr];
self.imageUrlArr = [NSMutableArray array];
self.imageArr = [NSMutableArray array];
for (NSInteger i = 0; i<self.imagesaveArr.count; i++) {
if(i == self.imagesaveArr.count - 1){
[self.imageArr addObject:self.imagesaveArr[0]];
[self.imageUrlArr addObject:self.imageUrlsaveArr[0]];
}else{
[self.imageArr addObject:self.imagesaveArr[i+1]];
[self.imageUrlArr addObject:self.imageUrlsaveArr[i+1]];
}
}
for (NSInteger i = 0; i<self.imageViewArr.count; i++) {
UIImageView *image = self.imageViewArr[i];
[image sd_setImageWithURL:[NSURL URLWithString:self.imageArr[i]]];
}
}
}
- (void)timeAction{
[self.backScrollView setContentOffset:CGPointMake(self.frame.size.width*2, 0) animated:YES];
}
controller使用
ScrollImageView *view2 = [[ScrollImageView alloc] initWithFrame:CGRectMake(0, 300,[UIScreen mainScreen].bounds.size.width , 200)];
[view2 reloadScrollView:[NSMutableArray arrayWithObjects:@"https://ss2.baidu.com/-vo3dSag_xI4khGko9WTAnF6hhy/super/whfpf%3D425%2C260%2C50/sign=a4b3d7085dee3d6d2293d48b252b5910/0e2442a7d933c89524cd5cd4d51373f0830200ea.jpg",
@"https://ss0.baidu.com/-Po3dSag_xI4khGko9WTAnF6hhy/super/whfpf%3D425%2C260%2C50/sign=a41eb338dd33c895a62bcb3bb72e47c2/5fdf8db1cb134954a2192ccb524e9258d1094a1e.jpg",
@"http://c.hiphotos.baidu.com/image/w%3D400/sign=c2318ff84334970a4773112fa5c8d1c0/b7fd5266d0160924c1fae5ccd60735fae7cd340d.jpg", nil] urlArr:[NSMutableArray arrayWithObjects:@"0----------",@"1-----------",@"2-----------",@"3-----------", nil]];
view2.delegate = self;
[self.view addSubview:view2];