UI开发----UIScrollView和UIPageControl简单模拟滚动视图

//  Created By 郭仔

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师傅领进门，修行在个人！自学才是王道！

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UIScrollView：

UIScrollView * scrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(20, 50, 200, 200)];

    scrollView.backgroundColor = [UIColor greenColor];
    [self.view addSubview:scrollView];
    // 设置内容大小，当contentSize大于scrollView.frame.size才能滑动
    scrollView.contentSize = CGSizeMake(1000, 1000);

    UIView * view = [[UIView alloc]initWithFrame:CGRectMake(50, 50, 50, 50)];
    view.backgroundColor = [UIColor redColor];
    [scrollView addSubview:view];
    scrollView.showsHorizontalScrollIndicator = YES;
    scrollView.showsVerticalScrollIndicator =  YES;
   // scrollView.contentOffset = CGPointMake(50, 50);
  //  scrollView.pagingEnabled = YES;
    UIView * view2 = [[UIView alloc]initWithFrame:CGRectMake(200, 50, 50, 50)];
    view2.backgroundColor = [UIColor blackColor];
    [scrollView addSubview:view2];
    [view2 release];
    scrollView.bounces = YES;）
    scrollView.scrollsToTop = YES;
    scrollView.scrollEnabled = YES;
    scrollView.alwaysBounceHorizontal = NO;
    scrollView.alwaysBounceVertical = YES;
    scrollView.minimumZoomScale = 0.5;
    scrollView.maximumZoomScale = 2;
    scrollView.zoomScale = 1.5;
    // 设置代理
    scrollView.delegate = self;

如果要实现缩放功能，则需要遵循UIScrollViewDelegate，设置自身为代理。

例如：

- (UIView *)
            viewForZoomingInScrollView:
            (UIScrollView *)scrollView
{
   // NSLog(@"%@",NSStringFromCGSize(scrollView.contentSize));
    return [scrollView.subviews objectAtIndex:0];

}

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UIPageView:

 UIPageControl *pageControl = [[UIPageControl alloc]initWithFrame:CGRectMake(50, 400, 200, 50)];
    pageControl.backgroundColor = [UIColor orangeColor];
    [self.view addSubview:pageControl];

    pageControl.numberOfPages = 5;
    pageControl.currentPage = 2;
    pageControl.pageIndicatorTintColor = [UIColor blueColor];
    pageControl.currentPageIndicatorTintColor = [UIColor whiteColor];
    [pageControl addTarget:self action:@selector(pageControlChange:) forControlEvents:UIControlEventValueChanged];

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滚动视图的模拟：

UIScrollView * scrollView = [[UIScrollView alloc]initWithFrame:self.view.bounds];
    //
    _scrollView = scrollView;
    [self.view addSubview:scrollView];
    scrollView.pagingEnabled = YES;
    //
    scrollView.delegate = self;

    scrollView.contentSize = CGSizeMake(320*5, 568);
    // 把图片名放到数组里
    NSArray * imagesName = [NSArray arrayWithObjects:@"1.png",@"2.png",@"3.png",@"4.png",@"5.png", nil];

    for (int i = 0; i< imagesName.count; i ++)

    {

        UIImage * img = [UIImage imageNamed:[imagesName objectAtIndex:i]];
        UIImageView * imageView = [[UIImageView alloc]initWithFrame:CGRectMake(i*320, 0, 320, 568)];
        imageView.image = img;

        [scrollView addSubview:imageView];
        [imageView release];
    }

        UIPageControl * pageControl = [[UIPageControl alloc]initWithFrame:CGRectMake(50, 400, 200, 50)];
        pageControl.numberOfPages = 5;
        [pageControl addTarget:self action:@selector(pageChanged:) forControlEvents:UIControlEventValueChanged];
        pageControl.pageIndicatorTintColor = [UIColor redColor];
        pageControl.currentPageIndicatorTintColor = [UIColor blackColor];
        //
        self.pageControl = pageControl;
        [self.view addSubview:pageControl];
        [pageControl release];

    [scrollView release];

方法的实现：

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    CGPoint offSet =  scrollView.contentOffset;
    int pageCount = offSet.x/320;
    _pageControl.currentPage = pageCount;

}

- (void)pageChanged:(UIPageControl *)control
{
    long currentPage = control.currentPage;
    CGPoint offSet = CGPointMake(currentPage * 320, 0);
    // 设置scrollView的偏移量
    [self.scrollView setContentOffset:offSet animated:YES];
}

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