13-常见UI控件之 UIPageControl分页

UIPageControl

1.   numberOfPages // 设置有多少页 默认为0

// 2) 设置页数

   [pageControl setNumberOfPages:kImageCount];

2.   currentPage  // 设置当前页

[pageControl setCurrentPage:0];

 

3.   pageIndicatorTintColor // 设置页码指示器颜色

 [pageControl setPageIndicatorTintColor:[UIColor blackColor]];

4.   currentPageIndicatorTintColor // 设置当前页码指示器颜色

 

[pageControl setCurrentPageIndicatorTintColor:[UIColor redColor]];

 

5. 添加分页控件的监听事件（监听值改变事件）

[pageControl addTarget:self action:@selector(pageChanged:)forControlEvents:UIControlEventValueChanged];

 

//    创建分页控件
    pageControl=[[UIPageControlalloc]initWithFrame:CGRectMake(0,250-10,375, 20)];
   
    pageControl.numberOfPages=imageNames.count;
   
    pageControl.currentPage=0;
   
    [pageControl addTarget:self action:@selector(pageAction:) forControlEvents:UIControlEventValueChanged];

    [headerView addSubview:pageControl];

-(void)pageAction:(UIPageControl*)pageControl{
   
    int page=pageControl.currentPage;
   
//    设置偏移量
//    [_scrollView setContentOffset:CGPointMake(page*375, 0) animated:YES];
   
//    滚动到某一个矩形区域，横向需要设置x偏移量，竖向设置y
    [_scrollView scrollRectToVisible:CGRectMake(page*375,0, 375,250) animated:YES];

}

 

//可以判断此协议，结束减速后在修改pageControl.currentPage
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{

    if (_scrollView==scrollView) {

       

        pageControl.currentPage = scrollView.contentOffset.x/375;

       

        currentPage;

    }

}

////////////////////////////////////////图片轮播器////////////////////////////////////////

@interface MJViewController () <UIScrollViewDelegate>
@property (weak,nonatomic) IBOutlet UIScrollView *scrollView;
@property (weak,nonatomic) IBOutlet UIPageControl *pageControl;
/**
 *  定时器
 */
@property (nonatomic,strong) NSTimer *timer;
@end

@implementation MJViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
   
    // 0.一些固定的尺寸参数
    CGFloat imageW = self.scrollView.frame.size.width;
    CGFloat imageH = self.scrollView.frame.size.height;
    CGFloat imageY = 0;
   
    // 1.添加5张图片到scrollView中
    for (int i =0; i<MJImageCount; i++) {
        UIImageView *imageView = [[UIImageViewalloc] init];
       
        // 设置frame
        CGFloat imageX = i * imageW;
        imageView.frame = CGRectMake(imageX, imageY, imageW, imageH);
       
        // 设置图片
        NSString *name = [NSStringstringWithFormat:@"img_0%d", i +1];
        imageView.image = [UIImageimageNamed:name];
       
        [self.scrollViewaddSubview:imageView];
    }
   
    // 2.设置内容尺寸
    CGFloat contentW = MJImageCount * imageW;
    self.scrollView.contentSize =CGSizeMake(contentW, 0);
   
    // 3.隐藏水平滚动条
    self.scrollView.showsHorizontalScrollIndicator =NO;
   
    // 4.分页
    self.scrollView.pagingEnabled =YES;
//    self.scrollView.delegate = self;
   
    // 5.设置pageControl的总页数
    self.pageControl.numberOfPages =MJImageCount;
   
    // 6.添加定时器(每隔2秒调用一次self的nextImage方法)
    [self addTimer];
}

/**
 *  添加定时器
 */
- (void)addTimer
{
    self.timer = [NSTimerscheduledTimerWithTimeInterval:2.0target:selfselector:@selector(nextImage)userInfo:nilrepeats:YES];
    [[NSRunLoop currentRunLoop] addTimer:self.timerforMode:NSRunLoopCommonModes];
}

/**
 *  移除定时器
 */
- (void)removeTimer
{
    [self.timerinvalidate];
    self.timer =nil;
}

- (void)nextImage
{
    // 1.增加pageControl的页码
    int page = 0;
    if (self.pageControl.currentPage ==MJImageCount - 1) {
        page = 0;
    } else {
        page = self.pageControl.currentPage +1;
    }
   
    // 2.计算scrollView滚动的位置
    CGFloat offsetX = page * self.scrollView.frame.size.width;
    CGPoint offset = CGPointMake(offsetX, 0);
    [self.scrollViewsetContentOffset:offset animated:YES];
}

#pragma mark - 代理方法
/**
 *  当scrollView正在滚动就会调用
 */
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    // 根据scrollView的滚动位置决定pageControl显示第几页
    CGFloat scrollW = scrollView.frame.size.width;
    int page = (scrollView.contentOffset.x + scrollW *0.5) / scrollW;
    self.pageControl.currentPage = page;
}

/**
 *  开始拖拽的时候调用
 */
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
    // 停止定时器(一旦定时器停止了,就不能再使用)
    [self removeTimer];
}

/**
 *  停止拖拽的时候调用
 */
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
    // 开启定时器
    [self addTimer];

}