IOS ——UI篇—— UIPageControl的使用以及与UIScrollView的结合

 

UIPageControl是分页符，在新闻类的APP中很常见，随着新闻页面的滚动，在屏幕中会有一些小点，也随着移动，用来分辨当前的页数，就是UIPageControl和ScrollView的结合使用；

直接给大家上代码，这样更有助于理解：

 

 1  page = [[UIPageControl alloc] initWithFrame:CGRectMake(20, 30, 200, 40)];
 2     page.backgroundColor = [UIColor clearColor];
 3     page.numberOfPages = 3;//设置页数（多少个点）
 4     page.currentPage = 0;//设置当前选中页
 5     NSLog(@"%d",page.currentPage);//获取当前选中页下标
 6     page.pageIndicatorTintColor = [UIColor greenColor];//未选中颜色
 7     page.currentPageIndicatorTintColor = [UIColor redColor];//当前选中的颜色
 8     [page addTarget:self action:@selector(change:) forControlEvents:UIControlEventValueChanged];
 9     [self.view addSubview:page];
10 
11 UIPageControl与UIScrollView 的结合使用
12 
13 #import "ViewController.h"
14 
15 @interface ViewController ()<UIScrollViewDelegate>{
16     UIPageControl *page;
17     UIScrollView  *scrollView;
18 }
19 
20 @end
21 
22 @implementation ViewController
23 
24 - (void)viewDidLoad {
25     [super viewDidLoad];
26 
27     page = [[UIPageControl alloc] initWithFrame:CGRectMake(20, 30, 200, 40)];
28     page.backgroundColor = [UIColor clearColor];
29     page.numberOfPages = 3;//设置页数（多少个点）
30     page.currentPage = 0;//设置当前选中页
31     NSLog(@"%d",page.currentPage);//获取当前选中页下标
32     page.pageIndicatorTintColor = [UIColor greenColor];//未选中颜色
33     page.currentPageIndicatorTintColor = [UIColor redColor];//当前选中的颜色
34     [page addTarget:self action:@selector(change:) forControlEvents:UIControlEventValueChanged];
35     [self.view addSubview:page];
36 
37     scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(20, 90, 300, 400)];
38     scrollView.contentSize = CGSizeMake(900, 0);
39     scrollView.delegate = self;
40     scrollView.pagingEnabled = YES;
41     [self.view addSubview:scrollView];
42 
43     UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 300, 400)];
44     view.backgroundColor = [UIColor grayColor];
45     [scrollView addSubview:view];
46 
47     UIView *view1 = [[UIView alloc] initWithFrame:CGRectMake(300, 0, 300, 400)];
48     view1.backgroundColor = [UIColor brownColor];
49     [scrollView addSubview:view1];
50 
51     UIView *view2 = [[UIView alloc] initWithFrame:CGRectMake(600, 0, 300, 400)];
52     view2.backgroundColor = [UIColor purpleColor];
53     [scrollView addSubview:view2];
54 
55 
56 }
57 
58 -(void)change:(id)page{
59     NSLog(@"--%zi",[page currentPage]);
60 
61CGPoint p = {[page currentPage]*300,0};//获取分页符当前的页数与view的宽相乘作为CGPoint的x

62  [scrollView setContentOffset:p animated:YES];//将p赋给scrollView的当前滚动位置，就建立了联系

63 }
64

65

 -(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
66 int index = scrollView.contentOffset.x/scrollView.frame.size.width;//当scrollView滚动停止时，将scrollView当前滚动到的位置除以view的宽，获得的值就是页数

67 page.currentPage = index; //将上面获得的页数赋给page，就是page的当前页

68 } 

69

70 - (void)didReceiveMemoryWarning {
71  [super didReceiveMemoryWarning];
72 // Dispose of any resources that can be recreated.

73 }
74 

75 @end