用
scrollview做，循环展示，1~10个可以比较简单，耗能比较少，假设100，1000，等等或者更多，总不能创建这么多个view。
这篇博客 主要介绍了 用3个view 来显示无限个 view，主要是通过- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView 来计算当前滑动了到第几个，然后调整 3个view的位置。
我自定义了一个view
EndlessLoopShowView
#import <UIKit/UIKit.h>
@class EndlessLoopShowView;
@protocol EndlessLoopShowViewDelegate <NSObject>
@optional
/* 滑动到第几个位置 **/
- (void)endlessLoop:(EndlessLoopShowView*)showView scrollToIndex:(NSInteger)currentIndex;
@end
@interface EndlessLoopShowView : UIView
/* 返回图片的显示，可以传入 image ，imageName ，url ,自己可以自定义 **/
@property (nonatomic,strong) NSArray * imageDataArr;
@property (nonatomic,weak) id <EndlessLoopShowViewDelegate>delegate;
@end
//
// EndlessLoopShowView.m
// EndlessLoopShowView
//
// Created by apple on 16/9/26.
// Copyright © 2016年 李重阳. All rights reserved.
//
#import "EndlessLoopShowView.h"
/*无限循环的视图 **/
@interface EndlessLoopShowView ()<UIScrollViewDelegate>
@property (nonatomic,strong) UIScrollView * scrollView;
@property (nonatomic,strong) UIImageView *leftImageView;
@property (nonatomic,strong) UIImageView *centerImageView;
@property (nonatomic,strong) UIImageView *rightImageView;
@property (nonatomic,assign) NSInteger currentIndex;/* 当前滑动到了哪个位置**/
@property (nonatomic,assign) NSInteger imageCount;/* 图片的总个数 **/
//http://www.cnblogs.com/kenshincui/p/3913885.html#ImageViewer
@end
@implementation EndlessLoopShowView
#pragma mark - 生命周期
- (instancetype)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
[self setupView];
}
return self;
}
- (void)setupView {
_currentIndex = -1;
[self addSubview:self.scrollView];
//添加图片控件
[self addImageViews];
}
- (void)layoutSubviews {
[super layoutSubviews];
self.scrollView.frame = self.bounds;
CGFloat imageW = CGRectGetWidth(self.scrollView.bounds);
CGFloat imageH = CGRectGetHeight(self.scrollView.bounds);
self.leftImageView.frame = CGRectMake(imageW*0, 0, imageW, imageH);
self.centerImageView.frame = CGRectMake(imageW*1, 0, imageW, imageH);
self.rightImageView.frame = CGRectMake(imageW*2, 0, imageW, imageH);
self.scrollView.contentSize= CGSizeMake(imageW*3, 0);
self.currentIndex = 0;
[self setScrollViewContentOffsetCenter];
}
#pragma mark - 私有方法
#pragma mark - get/set方法
- (UIScrollView *)scrollView {
if (_scrollView == nil) {
_scrollView=[[UIScrollView alloc]init];
//设置代理
_scrollView.delegate=self;
//设置分页
_scrollView.pagingEnabled=YES;
//去掉滚动条
_scrollView.showsHorizontalScrollIndicator=NO;
}
return _scrollView;
}
/* 重写 setCurrent 方法 并且赋值 **/
- (void)setCurrentIndex:(NSInteger)currentIndex {
if (_currentIndex != currentIndex) {
_currentIndex = currentIndex;
NSInteger leftImageIndex = (currentIndex+_imageCount-1)%_imageCount;
NSInteger rightImageIndex= (currentIndex+1)%_imageCount;
_centerImageView.image =[UIImage imageNamed:self.imageDataArr[currentIndex]];
_leftImageView.image =[UIImage imageNamed:self.imageDataArr[leftImageIndex]];
_rightImageView.image =[UIImage imageNamed:self.imageDataArr[rightImageIndex]];
[self setScrollViewContentOffsetCenter];
if ([self.delegate respondsToSelector:@selector(endlessLoop:scrollToIndex:)]) {
[self.delegate endlessLoop:self scrollToIndex:currentIndex];
}
}
}
#pragma mark 添加图片三个控件
-(void)addImageViews {
_leftImageView=[[UIImageView alloc]init];
_leftImageView.contentMode=UIViewContentModeScaleAspectFit;
[_scrollView addSubview:_leftImageView];
_centerImageView=[[UIImageView alloc]init];
_centerImageView.contentMode=UIViewContentModeScaleAspectFit;
[_scrollView addSubview:_centerImageView];
_rightImageView=[[UIImageView alloc]init];
_rightImageView.contentMode=UIViewContentModeScaleAspectFit;
[_scrollView addSubview:_rightImageView];
}
/* 把scrollView 偏移到中心位置 **/
- (void)setScrollViewContentOffsetCenter {
[self.scrollView setContentOffset:CGPointMake(CGRectGetWidth(self.scrollView.bounds), 0) animated:NO];
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
CGPoint offset=[_scrollView contentOffset];
if (offset.x>CGRectGetWidth(scrollView.frame)) { //向右滑动
self.currentIndex=(self.currentIndex+1)%_imageCount;
}else if(offset.x<CGRectGetWidth(scrollView.frame)){ //向左滑动
self.currentIndex=(self.currentIndex+_imageCount-1)%_imageCount;
}
}
#pragma mark - 公共方法
- (void)setImageDataArr:(NSArray *)imageDataArr {
_imageDataArr = imageDataArr;
self.imageCount = imageDataArr.count;
self.currentIndex = 0;
}
@end
用法
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
EndlessLoopShowView * showView = [[EndlessLoopShowView alloc]initWithFrame:CGRectMake(0, 100, 200, 200)];
showView.backgroundColor = [UIColor redColor];
showView.imageDataArr = @[@"1",@"2",@"3",@"4",@"5"];
showView.delegate = self;
[self.view addSubview:showView];
}
- (void)endlessLoop:(EndlessLoopShowView *)showView scrollToIndex:(NSInteger)currentIndex {
NSLog(@"currentIndex = %ld",currentIndex);
}
连接
gitHub
