iOS轮播图（ios轮播图实现原理）

IOS 开发之网络图片轮播图的实现

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iOS轮播图（ios轮播图实现原理）

1.使用

1 2 3 4 LJPhotoGroupView *_ljPhotoGroupView = [[LJPhotoGroupView alloc]initWithItem:self.ljUrlArray]; _ljPhotoGroupView.backgroundColor = [UIColor blackColor]; _ljPhotoGroupView.frame = CGRectMake(0, 0, kDEVICEWIDTH, kDEVICEHEIGHT); [_ljPhotoGroupView showHintView:self];

2.源码

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 #import "LJPhotoGroupView.h" #import "LJWebIDataManager.h" @interface LJPhotoGroupCellView() @property (nonatomic, strong) UIImageView *ljImageview; @end @implementation LJPhotoGroupCellView - (instancetype)initWithFrame:(CGRect)frame url:(NSString*)imageurl { self = [super initWithFrame:frame]; if (self) { [self addSubview:self.ljImageview]; ／／这里大家可以换成自己的网络请求图片的方法 [[LJWebIDataManager sharedInstances]retrieveData:imageurl successBlock:^(NSData *netData, NSString *progressStr, BOOL isFinished) { //在主线程中刷新界面 dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ UIImage *_ljImage = [UIImage imageWithData: netData scale:0.3]; @myWeakify(self); dispatch_async(dispatch_get_main_queue(), ^{ @myStrongify(self); self.ljImageview.image = _ljImage; }); }); }]; } return self; } - (UIImageView*)ljImageview { if (!_ljImageview) { _ljImageview = UIImageView.new; _ljImageview.frame = CGRectMake(15, 0, kDEVICEWIDTH - 30, 130); _ljImageview.backgroundColor = [UIColor redColor]; UIGestureRecognizer *_tap = [[UIGestureRecognizer alloc]initWithTarget:self action:@selector(dismissHintView)]; [_ljImageview addGestureRecognizer:_tap]; } return _ljImageview; } @end @interface LJPhotoGroupView()<UIScrollViewDelegate> @property (nonatomic, strong) UIScrollView *ljScrollView; @property (nonatomic, strong) NSArray *ljItemArray; @property (nonatomic, strong) UIImageView *ljImageview; @property (nonatomic, strong) UIPageControl *ljPageControl; @end @implementation LJPhotoGroupView - (instancetype)initWithItem:(NSArray*)ljArray { self = [super init]; if (self) { self.ljItemArray = [NSArray arrayWithArray:ljArray]; [self addSubview:self.ljScrollView]; [self addSubview:self.ljPageControl]; for (int i = 0; i < self.ljItemArray.count; i++) { //方法一：直接设置每个cell的X坐标 // LJPhotoGroupCellView *_cell = [[LJPhotoGroupCellView alloc]initWithFrame:CGRectMake((kDEVICEWIDTH )*i, 0, kDEVICEWIDTH, 130) url:self.ljItemArray[i]]; //方法二:先不用考虑cell的X坐标，在下面设置X的坐标 LJPhotoGroupCellView *cell = [[LJPhotoGroupCellView alloc]initWithFrame:self.ljScrollView.bounds url:self.ljItemArray[i]]; UITapGestureRecognizer *_tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(dismissHintView)]; [cell addGestureRecognizer:_tap]; [self.ljScrollView addSubview:cell]; } //方法二:设置cell的X坐标 // 计算imageView的位置 [self.ljScrollView.subviews enumerateObjectsUsingBlock:^(LJPhotoGroupCellView *cell, NSUInteger idx, BOOL *stop) { // 调整x => origin => frame CGRect frame = cell.frame; frame.origin.x = idx * frame.size.width; cell.frame = frame; }]; self.ljPageControl.currentPage = 0; } return self; } - (UIScrollView*)ljScrollView { if (!_ljScrollView) { _ljScrollView = UIScrollView.new; _ljScrollView.frame = CGRectMake(0, 250, kDEVICEWIDTH, 130); _ljScrollView.delegate = self; //_scrollView.scrollsToTop = NO; _ljScrollView.pagingEnabled = YES; _ljScrollView.contentSize = CGSizeMake(_ljScrollView.bounds.size.width * self.ljItemArray.count, 130); //_scrollView.alwaysBounceHorizontal = groupItems.count > 1; // _scrollView.showsHorizontalScrollIndicator = NO; //_scrollView.showsVerticalScrollIndicator = NO; //_scrollView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight; //_scrollView.delaysContentTouches = NO; //_scrollView.canCancelContentTouches = YES; } return _ljScrollView; } - (UIPageControl *)ljPageControl { if (_ljPageControl == nil) { // 分页控件，本质上和scrollView没有任何关系，是两个独立的控件 _ljPageControl = [[UIPageControl alloc] init]; // 总页数 _ljPageControl.numberOfPages = self.ljItemArray.count; CGSize size = [_ljPageControl sizeForNumberOfPages:self.ljItemArray.count]; _ljPageControl.bounds = CGRectMake(0, 0, size.width, size.height); _ljPageControl.center = CGPointMake(self.center.x, 380); // 设置颜色 _ljPageControl.pageIndicatorTintColor = [UIColor redColor]; //当前页面的颜色 _ljPageControl.currentPageIndicatorTintColor = [UIColor whiteColor]; [_ljPageControl addTarget:self action:@selector(pageChanged:) forControlEvents:UIControlEventValueChanged]; } return _ljPageControl; } // 分页控件的监听方法 - (void)pageChanged:(UIPageControl *)page { NSLog(@"%ld", (long)page.currentPage); // 根据页数，调整滚动视图中的图片位置 contentOffset self.scrollView.bounds.size.width CGFloat x = page.currentPage * (kDEVICEWIDTH); [self.ljScrollView setContentOffset:CGPointMake(x, 0) animated:YES]; } - (UIImageView*)ljImageview { if (!_ljImageview) { _ljImageview = UIImageView.new; _ljImageview.frame = CGRectMake(0, 0, kDEVICEWIDTH, kDEVICEHEIGHT); _ljImageview.backgroundColor = [UIColor redColor]; UIGestureRecognizer *_tap = [[UIGestureRecognizer alloc]initWithTarget:self action:@selector(dismissHintView)]; [_ljImageview addGestureRecognizer:_tap]; } return _ljImageview; } - (void)scrollViewDidScroll:(UIScrollView *)scrollView { //CGFloat floatPage = _scrollView.contentOffset.x / _scrollView.width; //NSInteger page = _scrollView.contentOffset.x / _scrollView.width; } - (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{ if (!decelerate) { } } #pragma mark - ScrollView的代理方法 // 滚动视图停下来，修改页面控件的小点（页数） - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView { // 停下来的当前页数 NSLog(@"%@", NSStringFromCGPoint(scrollView.contentOffset)); // 计算页数 int page = scrollView.contentOffset.x / scrollView.bounds.size.width; self.ljPageControl.currentPage = page; } - (void)showHintView:(UIView*)view { //[view addSubview:self]; [[UIApplication sharedApplication].delegate.window.rootViewController.view addSubview:self]; self.alpha = 0.0; [UIView animateWithDuration:0.3 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{ self.alpha = 1.0; } completion:^(BOOL finished) { }]; } - (void)dismissHintView { [UIView animateWithDuration:0.3 delay:0 options:UIViewAnimationOptionCurveEaseIn animations:^{ self.alpha = 0.0; } completion:^(BOOL finished){ [self removeFromSuperview]; }]; } @end