标签：
场景：
在开发工作中，有时我们需要实现一组图片循环滚动的情况。当我们使用 UIScrollView 结合 UIImageView 来实现时，一般 UIImageView 会尽量考虑重用，下面例子是以（左中右）三个 UIImageView 的使用，其实也可以考虑使用 两个 UIImageView 实现的情况。这样避免 一组图片多少个就对应多少个 UIImageView 所导致占用过多内存的情况。
效果如下：
ViewController.h
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
|
#import <uikit uikit.h="">@interface ViewController : UIViewController <uiscrollviewdelegate>@property (strong, nonatomic) UIScrollView *scrV;@property (strong, nonatomic) UIPageControl *pageC;@property (strong, nonatomic) UIImageView *imgVLeft;@property (strong, nonatomic) UIImageView *imgVCenter;@property (strong, nonatomic) UIImageView *imgVRight;@property (strong, nonatomic) UILabel *lblImageDesc;@property (strong, nonatomic) NSMutableDictionary *mDicImageData;@property (assign, nonatomic) NSUInteger currentImageIndex;@property (assign, nonatomic) NSUInteger imageCount;@end</uiscrollviewdelegate></uikit> |
ViewController.m
|
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
|
#import "ViewController.h"#define kWidthOfScreen [[UIScreen mainScreen] bounds].size.width#define kHeightOfScreen [[UIScreen mainScreen] bounds].size.height#define kImageViewCount 3@interface ViewController ()/** * 加载图片数据 */- (void)loadImageData;/** * 添加滚动视图 */- (void)addScrollView;/** * 添加三个图片视图到滚动视图内 */- (void)addImageViewsToScrollView;/** * 添加分页控件 */- (void)addPageControl;/** * 添加标签；用于图片描述 */- (void)addLabel;/** * 根据当前图片索引设置信息 * * @param currentImageIndex 当前图片索引；即中间 */- (void)setInfoByCurrentImageIndex:(NSUInteger)currentImageIndex;/** * 设置默认信息 */- (void)setDefaultInfo;/** * 重新加载图片 */- (void)reloadImage;- (void)layoutUI;@end@implementation ViewController- (void)viewDidLoad { [super viewDidLoad]; [self layoutUI];}- (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated.}- (void)loadImageData { NSString *path = [[NSBundle mainBundle] pathForResource:@"ImageInfo" ofType:@"plist"]; _mDicImageData = [NSMutableDictionary dictionaryWithContentsOfFile:path]; _imageCount = _mDicImageData.count;}- (void)addScrollView { _scrV = [[UIScrollView alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; _scrV.contentSize = CGSizeMake(kWidthOfScreen * kImageViewCount, kHeightOfScreen); _scrV.contentOffset = CGPointMake(kWidthOfScreen, 0.0); _scrV.pagingEnabled = YES; _scrV.showsHorizontalScrollIndicator = NO; _scrV.delegate = self; [self.view addSubview:_scrV];}- (void)addImageViewsToScrollView { //图片视图；左边 _imgVLeft = [[UIImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, kWidthOfScreen, kHeightOfScreen)]; _imgVLeft.contentMode = UIViewContentModeScaleAspectFit; [_scrV addSubview:_imgVLeft]; //图片视图；中间 _imgVCenter = [[UIImageView alloc] initWithFrame:CGRectMake(kWidthOfScreen, 0.0, kWidthOfScreen, kHeightOfScreen)]; _imgVCenter.contentMode = UIViewContentModeScaleAspectFit; [_scrV addSubview:_imgVCenter]; //图片视图；右边 _imgVRight = [[UIImageView alloc] initWithFrame:CGRectMake(kWidthOfScreen * 2.0, 0.0, kWidthOfScreen, kHeightOfScreen)]; _imgVRight.contentMode = UIViewContentModeScaleAspectFit; [_scrV addSubview:_imgVRight];}- (void)addPageControl { _pageC = [UIPageControl new]; CGSize size= [_pageC sizeForNumberOfPages:_imageCount]; //根据页数返回 UIPageControl 合适的大小 _pageC.bounds = CGRectMake(0.0, 0.0, size.width, size.height); _pageC.center = CGPointMake(kWidthOfScreen / 2.0, kHeightOfScreen - 80.0); _pageC.numberOfPages = _imageCount; _pageC.pageIndicatorTintColor = [UIColor whiteColor]; _pageC.currentPageIndicatorTintColor = [UIColor brownColor]; _pageC.userInteractionEnabled = NO; //设置是否允许用户交互；默认值为 YES，当为 YES 时，针对点击控件区域左（当前页索引减一，最小为0）右（当前页索引加一，最大为总数减一），可以编写 UIControlEventValueChanged 的事件处理方法 [self.view addSubview:_pageC];}- (void)addLabel { _lblImageDesc = [[UILabel alloc] initWithFrame:CGRectMake(0.0, 40.0, kWidthOfScreen, 40.0)]; _lblImageDesc.textAlignment = NSTextAlignmentCenter; _lblImageDesc.textColor = [UIColor whiteColor]; _lblImageDesc.font = [UIFont boldSystemFontOfSize:[UIFont labelFontSize]]; _lblImageDesc.text = @"Fucking now."; [self.view addSubview:_lblImageDesc];}- (void)setInfoByCurrentImageIndex:(NSUInteger)currentImageIndex { NSString *currentImageNamed = [NSString stringWithFormat:@"%lu.png", (unsigned long)currentImageIndex]; _imgVCenter.image = [UIImage imageNamed:currentImageNamed]; _imgVLeft.image = [UIImage imageNamed:[NSString stringWithFormat:@"%lu.png", (unsigned long)((_currentImageIndex - 1 + _imageCount) % _imageCount)]]; _imgVRight.image = [UIImage imageNamed:[NSString stringWithFormat:@"%lu.png", (unsigned long)((_currentImageIndex + 1) % _imageCount)]]; _pageC.currentPage = currentImageIndex; _lblImageDesc.text = _mDicImageData[currentImageNamed];}- (void)setDefaultInfo { _currentImageIndex = 0; [self setInfoByCurrentImageIndex:_currentImageIndex];}- (void)reloadImage { CGPoint contentOffset = [_scrV contentOffset]; if (contentOffset.x > kWidthOfScreen) { //向左滑动 _currentImageIndex = (_currentImageIndex + 1) % _imageCount; } else if (contentOffset.x < kWidthOfScreen) { //向右滑动 _currentImageIndex = (_currentImageIndex - 1 + _imageCount) % _imageCount; } [self setInfoByCurrentImageIndex:_currentImageIndex];}- (void)layoutUI { self.view.backgroundColor = [UIColor blackColor]; [self loadImageData]; [self addScrollView]; [self addImageViewsToScrollView]; [self addPageControl]; [self addLabel]; [self setDefaultInfo];}#pragma mark - UIScrollViewDelegate- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView { [self reloadImage]; _scrV.contentOffset = CGPointMake(kWidthOfScreen, 0.0); _pageC.currentPage = _currentImageIndex; NSString *currentImageNamed = [NSString stringWithFormat:@"%lu.png", (unsigned long)_currentImageIndex]; _lblImageDesc.text = _mDicImageData[currentImageNamed];}@end |
ImageInfo.plist
使用UIScrollView 结合 UIImageView 实现图片循环滚动
标签：
原文地址：http://www.cnblogs.com/xiguain/p/4708146.html
