用UIScrollView和UIPageControl簡單模拟相冊功能

用一個大的UIScrollView裡放一些小的UIScrollView，小的UIScrollView裡面放UIImageView來顯示圖檔，切換圖檔的時候通過UIPageControl來顯示的圖檔的位置，通過切換頁也可以切換圖檔

1.UIScrollView

用到的屬性

@property(nonatomic)        CGPoint                      contentOffset;                 // default CGPointZero  偏移

@property(nonatomic)        CGSize                       contentSize;                   // default CGSizeZero    可以滾動的區域

@property(nonatomic)        BOOL                         bounces;                       // default YES. if YES, bounces past edge of content and back again  到邊緣之後是否可以拖動

@property(nonatomic,assign)id<UIScrollViewDelegate>      delegate;                      // default nil. weak reference   協定代理

用到的代理方法

- (void)scrollViewDidScroll:(UIScrollView *)scrollView;                                              // any offset changes 滾動發生

- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView;    // return a view that will be scaled. if delegate returns nil, nothing happens 得到正在放大的視圖

2，UIPageControl

用到的屬性

@property(nonatomic)NSInteger numberOfPages;         // default is 0 頁數

@property(nonatomic)NSInteger currentPage;           // default is 0. value pinned to 0..numberOfPages-1 目前頁

3.簡單實作

.h中添加兩個屬性或成員

{

    UIScrollView *_scrollView;

    UIPageControl *_pageControl;

}

.m中

- (void)viewDidLoad

{

    [superviewDidLoad];

// Do any additional setup after loading the view.

    _scrollView=[[UIScrollViewalloc]initWithFrame:CGRectMake(0,20,320,180)];

    [_scrollViewsetBackgroundColor:[UIColorgrayColor]];

    [_scrollViewsetMaximumZoomScale:4.0f];//放大比例

    [_scrollViewsetMinimumZoomScale:0.1f];//縮小比例

    [_scrollViewsetShowsVerticalScrollIndicator:false];//隐藏滑動訓示器

    [_scrollViewsetBounces:NO];//到邊緣之後是否可以持續拉動的效果

    [_scrollViewsetContentSize:CGSizeMake(2880   ,0)];//大小

    _scrollView.delegate=self;//設定代理人

    [_scrollViewsetPagingEnabled:YES];//每次拖動，總是拖到新一頁

    [_scrollViewsetContentOffset:CGPointMake(640,0)];

    //添加圖檔

    for (int i=1; i<10; i++) {

        UIScrollView *scrollView=[[UIScrollViewalloc]initWithFrame:CGRectMake(i*320-320,0,320, 180)];

        //建立子滾動視圖

        NSString *str=[NSStringstringWithFormat:@"%d.jpg",i];

        UIImageView *imageView=[[UIImageViewalloc]initWithImage:[UIImageimageNamed:str]];

        //建立imageView添加到子滾動視圖

        [imageView setFrame:CGRectMake(0,0,320, 180)];

        [scrollView addSubview:imageView];

        [imageView release];

        scrollView.delegate=self;//給子滾動視圖添加代理

        [scrollView setMaximumZoomScale:1.5f];

        [scrollView setMinimumZoomScale:0.1f];

        [_scrollView addSubview:scrollView];//子滾動視圖添加到大的滾動視圖上面

        [scrollView release];

    }

    //添加頁控制

    _pageControl=[[UIPageControlalloc]initWithFrame:CGRectMake(0,240,320,40 )];

    [_pageControlsetBackgroundColor:[UIColorgrayColor]];

    [_pageControladdTarget:selfaction:@selector(pageControlAction:)forControlEvents:UIControlEventValueChanged];

    [_pageControlsetNumberOfPages:9];

    [_pageControlsetPageIndicatorTintColor:[UIColorredColor]];

    [self.viewaddSubview:_pageControl];

    [_pageControl release];

    [self.viewaddSubview:_scrollView];

    [_scrollView release];

}

//得到目前要放大的視圖

-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView

{

    NSArray *viewArr=[scrollView subviews];//得到子視圖

    return    [viewArr objectAtIndex:0];

}

//頁切換動作，換到下一張圖檔

-(void)pageControlAction:(id)sender

{

    if ([sender isKindOfClass:[UIPageControlclass]]) {

        UIPageControl *pagecontrol=(UIPageControl *)sender;

        NSLog(@"%d",pagecontrol.currentPage);

        //每次切換到下一張的時候，讓它顯示原來的比例

        UIScrollView *scrollView=[[_scrollViewsubviews]objectAtIndex:pagecontrol.currentPage];

        [scrollView setZoomScale:1.0];

        [_scrollView setContentOffset:CGPointMake(320*pagecontrol.currentPage,0 )];

    }

}

//滾動動作發生

-(void)scrollViewDidScroll:(UIScrollView *)scrollView

{

    NSLog(@"滾動發生");

    NSLog(@"content offset=%@",NSStringFromCGPoint(scrollView.contentOffset));

    int page=scrollView.contentOffset.x/320;

    [_pageControlsetCurrentPage:page];

    NSLog(@"page=%d",page);

}

效果圖