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//
// GMInfinitelView.m
//
//
// Created by wangyang on 10/12/15.
// Copyright (c) 2015年 Wanmeichuangyi. All rights reserved.
//
#import "GMInfiniteScrollView.h"
#import "GMImageView.h"
#define IMAGE_TAG 1000
@implementation GMInfiniteScrollView
- (void)setup{
[super setup];
// 显示的是图片数组里的第一张图片
// 和数组是+1关系
_currentPage = 0;
_scrollView = [[UIScrollView alloc] initWithFrame:self.bounds];
_scrollView.backgroundColor = UIColor.whiteColor;
_scrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
_scrollView.showsHorizontalScrollIndicator = NO;
_scrollView.showsVerticalScrollIndicator = NO;
_scrollView.pagingEnabled = YES;
_scrollView.delegate = self;
_scrollView.scrollsToTop = NO;
[self addSubview:_scrollView];
self.pageControl = [UIPageControl new];
self.pageControl.currentPage = 0;
self.pageControl.hidesForSinglePage = YES;
[self addSubview:self.pageControl];
self.imageContentMode = UIViewContentModeScaleAspectFill;
// 在应用后台时关闭播放，前台时开启
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(stopRolling) name:UIApplicationDidEnterBackgroundNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(startRolling) name:UIApplicationWillEnterForegroundNotification object:nil];
}
- (void)layoutSubviews{
[super layoutSubviews];
self.pageControl.frame = CGRectMake(0, self.frame.size.height-15, self.frame.size.width, 15);
self.pageControl.center = CGPointMake(self.frame.size.width / 2, self.pageControl.center.y);
}
- (void)dealloc
{
self.delegate = nil;
[[NSNotificationCenter defaultCenter] removeObserver:self];
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(rollingScrollAction) object:nil];
}
#pragma mark - Setter
- (void)setImageArray:(NSArray *)imageArray{
_imageArray = imageArray;
if(_imageArray.count == 0) {
return;
}
// 如果只有一个，不允许滑动
_scrollView.scrollEnabled = _imageArray.count == 1 ? NO : YES;
_scrollView.contentSize = CGSizeMake(_scrollView.frame.size.width * 3,
_scrollView.frame.size.height);
for (NSInteger i = 0; i < 3; i++){
CGRect frame = CGRectOffset(_scrollView.bounds, _scrollView.frame.size.width * i, 0);
GMImageView *imageView = [[GMImageView alloc] initWithFrame:frame];
imageView.userInteractionEnabled = YES;
imageView.clipsToBounds = YES;
imageView.contentMode = self.imageContentMode;
imageView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
imageView.tag = i + IMAGE_TAG;
UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTap:)];
[imageView addGestureRecognizer:singleTap];
[_scrollView addSubview:imageView];
}
self.pageControl.numberOfPages = self.self.imageArray.count;
_currentPage = 1;
[self refreshScrollView];
}
#pragma mark - Custom Method
- (void)refreshScrollView{
NSArray *imageArray = [self getDisplayImagesWithPageIndex:_currentPage];
for (NSInteger i = 0; i < 3; i++){
GMImageView *imageView = (GMImageView *)[_scrollView viewWithTag:i + IMAGE_TAG];
NSString *url = imageArray[i];
[imageView setImageWithUrlString:url placeHolder:nil];
}
// 水平滚动
_scrollView.contentOffset = CGPointMake(_scrollView.frame.size.width, 0);
self.pageControl.currentPage = _currentPage-1;
}
- (NSArray *)getDisplayImagesWithPageIndex:(NSInteger)page{
NSInteger pre = [self getPageIndex:_currentPage-1];
NSInteger last = [self getPageIndex:_currentPage+1];
NSMutableArray *images = [NSMutableArray arrayWithCapacity:0];
[images addObject:[self.imageArray objectAtIndex:pre-1]];
[images addObject:[self.imageArray objectAtIndex:_currentPage-1]];
[images addObject:[self.imageArray objectAtIndex:last-1]];
return images;
}
- (NSInteger)getPageIndex:(NSInteger)index{
// value＝1为第一张，value = 0为前面一张
if (index == 0)
{
index = self.imageArray.count;
}
if (index == self.imageArray.count + 1)
{
index = 1;
}
return index;
}
#pragma mark - UIScrollViewDelegate
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
NSInteger x = scrollView.contentOffset.x;
//取消已加入的延迟线程
if (self.enableRolling)
{
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(rollingScrollAction) object:nil];
}
// 往下翻一张
if (x >= 2 * _scrollView.frame.size.width)
{
_currentPage = [self getPageIndex:_currentPage+1];
[self refreshScrollView];
}
if (x <= 0)
{
_currentPage = [self getPageIndex:_currentPage-1];
[self refreshScrollView];
}
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
_scrollView.contentOffset = CGPointMake(_scrollView.frame.size.width, 0);
if (self.enableRolling)
{
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(rollingScrollAction) object:nil];
[self performSelector:@selector(rollingScrollAction) withObject:nil afterDelay:self.timeInterval inModes:[NSArray arrayWithObject:NSRunLoopCommonModes]];
}
}
#pragma mark - Action
- (void)startRolling{
if (self.imageArray.count == 0 || self.imageArray.count == 1){
return;
}
[self stopRolling];
self.enableRolling = YES;
[self performSelector:@selector(rollingScrollAction) withObject:nil afterDelay:self.timeInterval];
}
- (void)stopRolling{
self.enableRolling = NO;
//取消已加入的延迟线程
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(rollingScrollAction) object:nil];
}
- (void)rollingScrollAction{
// 滑动动画由我们自己完成
[UIView animateWithDuration:0.25 animations:^{
_scrollView.contentOffset = CGPointMake(1.99*_scrollView.frame.size.width, 0);
} completion:^(BOOL finished) {
if (finished)
{
_currentPage = [self getPageIndex:_currentPage+1];
[self refreshScrollView];
if (self.enableRolling)
{
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(rollingScrollAction) object:nil];
[self performSelector:@selector(rollingScrollAction) withObject:nil afterDelay:self.timeInterval inModes:[NSArray arrayWithObject:NSRunLoopCommonModes]];
}
}
}];
}
- (void)handleTap:(UITapGestureRecognizer *)tap{
if ([self.delegate respondsToSelector:@selector(infiniteScrollView:didSelectIndex:)]){
[self.delegate infiniteScrollView:self didSelectIndex:_currentPage-1];
}
}
@end