一、UIScrollView

UIScrollView是所有滾動視圖的基礎，很重要，主要用于輪播圖，相冊等功能
當內(nèi)容超過一個屏幕時，為了將內(nèi)容完整呈現(xiàn)，就可以使用UIScrollView

重要屬性
1.設置滾動范圍：contentSize：返回值為CGSize
2.設置分頁效果：(BOOL)pagingEnabled
3.偏移量：contentOffset：返回值為CGPoint，改變偏移量可以切換子視圖
4.設置滾動條是否顯示：
showsHorizontalScrollIndicator 水平方向
showsVerticallndicator 垂直方向
5.反彈效果：(BOOL)bounces

和縮放相關的屬性
1.最小縮放比例：minimumZoomScale：返回值CGFloat
2.最大縮放比例：maximumZoomScale：返回值CGFloat
3.當前的縮放比例：zoomScale

重要的位置屬性：automaticallyAdjustsScrollViewInsets
當視圖上有導航欄的時候，會比較麻煩，這個屬性不是ScrollView的屬性，是視圖控制器的屬性

當 automaticallyAdjustsScrollViewInsets 為 NO 時，滾動視圖就不會隨便延展
automaticallyAdjustsScrollViewInsets為 YES 時，滾動視圖會自動延伸

 

#define WIDTH self.view.frame.size.width  
#define HEIGHT self.view.frame.size.height  
  
-(void)viewDidLoad  
{  
      
#pragma mark UIScroll  
      
    //滾動視圖學習，當內(nèi)容超過一個屏幕時，為了將內(nèi)容完整呈現(xiàn)  
    UIScrollView *myScrollView = [[UIScrollView alloc]initWithFrame:self.view.frame];  
      
    //設置滾動區(qū)域，這個屬性控制著能滾動的服務，這里設置為3倍屏幕寬度  
    myScrollView.contentSize = CGSizeMake(WIDTH*3, HEIGHT);  
      
    //設置分頁效果  
    myScrollView.pagingEnabled = YES;  
  
    //滾動條樣式  
    myScrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;  
      
    //隱藏水平/垂直滾動條  
    myScrollView.showsHorizontalScrollIndicator = NO;  
    myScrollView.showsVerticalScrollIndicator = NO;  
      
    //設置tag  
    myScrollView.tag = 1001;  
      
    //設置反彈效果  
    myScrollView.bounces = YES;  
  
    //設置代理  
    myScrollView.delegate = self;  
      
    //偏移量,相對滾動視圖的原點的位置，屏幕從偏移量這個點開始顯示滾動視圖的內(nèi)容  
    myScrollView.contentOffset = CGPointMake(WIDTH,0);  
      
    //為滾動視圖添加子視圖  
    for (int i = 0; i < 3; i++) {  
        UIView *myView = [[UIView alloc]initWithFrame:CGRectMake(WIDTH*i, 0, WIDTH, HEIGHT)];  
          
        myView.backgroundColor = [UIColor colorWithRed:arc4random()%256/255.0 green:arc4random()%256/255.0 blue:arc4random()%256/255.0 alpha:1];  
       // [myScrollView addSubview:myView];  
    }  
      
    for (int i = 0; i < 3; i++) {  
        UILabel *myLabel = [[UILabel alloc]initWithFrame:CGRectMake(WIDTH*i, 0, WIDTH, HEIGHT)];  
        myLabel.font = [UIFont systemFontOfSize:220];  
        myLabel.text = [NSString stringWithFormat:@"第%d頁",i];  
        //讓字體根據(jù)Label的width適應大小  
        myLabel.adjustsFontSizeToFitWidth = YES;  
  
        //顏色隨機  
        myLabel.backgroundColor = [UIColor colorWithRed:arc4random()%256/255.0 green:arc4random()%256/255.0 blue:arc4random()%256/255.0 alpha:1];  
        [myScrollView addSubview:myLabel];  
    }  
      
    //添加滾動視圖到父視圖  
   [self.view addSubview:myScrollView];  
}  

這樣就生成了三個頁面UILabel，可以通過手勢拖拽進行交換

二、UIScrollView的代理方法

UIScrollView的代理方法主要實現(xiàn)兩部分內(nèi)容：

1.監(jiān)視視圖的滾動狀態(tài)

首先看看監(jiān)視視圖的縮放

//開始拖拽視圖，只有觸摸對象滑動才會觸發(fā)  
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView  
{  
   // NSLog(@"開始拖拽");  
}  
  
//停止拖拽  
-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate  
{  
   // NSLog(@"拖拽停止");  
}  
  
//拖拽結(jié)束，松開的時候  
-(void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset  
     
  
//正在滾動  
-(void)scrollViewDidScroll:(UIScrollView *)scrollView  
  
//視圖結(jié)束減速  
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView  
  
  
//將要開始減速  
-(void)scrollViewWillBeginDecelerating:(UIScrollView *)scrollView  
     
  
//拖動到了頂端  
-(void)scrollViewDidScrollToTop:(UIScrollView *)scrollView  

2.控制視圖的縮放

//返回需要縮放的視圖，必須為scrollView的子視圖
-(UIView*)viewForZoominglnScrollView:(UIScrollView*)scrollView：

//縮放結(jié)束  
-(void)scrollViewDidEndZooming:(UIScrollView *)scrollView withView:(UIView *)view atScale:(CGFloat)scale  
  
//變換中  
-(void)scrollViewDidZoom:(UIScrollView *)scrollView  
        
//將要開始變形  
-(void)scrollViewWillBeginZooming:(UIScrollView *)scrollView withView:(UIView *)view  

三、一個比較復雜的實例

現(xiàn)在要實現(xiàn)一個簡單的相冊功能，每個照片還可以通過捏合來進行縮放，切換圖片之后之前的圖片要恢復原比例
同時添加了一個UIPageControl控件，與UIScrollView配合切換視圖
這里總共有三張圖片，加了第四張與第一張相同，用來模擬循環(huán)狀態(tài)

#define WIDTH (self.view.frame.size.width)  
#define HEIGHT (self.view.frame.size.height)  
  
#import "SecondViewController.h"  
#import "PhotoScrollView.h"  
  
  
@interface SecondViewController ()<UIScrollViewDelegate>  
  
  
@property (nonatomic,retain)UIScrollView *albumScrollView;//相冊滾動視圖  
@property (nonatomic,retain)UIPageControl *albunPageControl;//頁數(shù)小白點  
@property (nonatomic,retain)NSMutableArray *photoArray;//照片數(shù)組  
  
@end  
  
@implementation SecondViewController  
  
//_albumScrollView懶加載  
-(UIScrollView *)albumScrollView  
{  
    if (!_albumScrollView) {  
        _albumScrollView = [[UIScrollView alloc]initWithFrame:self.view.frame];  
        _albumScrollView.contentSize = CGSizeMake(WIDTH*5, HEIGHT);  
        //翻頁設置  
        _albumScrollView.pagingEnabled = YES;  
    }  
    return _albumScrollView;  
}  
-(UIPageControl *)albunPageControl  
{  
    if (!_albunPageControl) {  
        _albunPageControl = [[UIPageControl alloc]initWithFrame:CGRectMake(0, 600, WIDTH, 50)];  
        //添加方法  
       // [_albunPageControl addTarget:self action:@selector(pageControlChangeView:) forControlEvents:UIControlEventValueChanged];  
    }  
    return _albunPageControl;  
}  
//數(shù)組懶加載  
-(NSMutableArray *)photoArray  
{  
    if (!_photoArray) {  
        _photoArray = [[NSMutableArray alloc]initWithCapacity:2];  
    }  
    return _photoArray;  
}  
  
-(void)viewDidLoad  
{  
    //添加滾動圖并設置代理  
    [self.view addSubview:self.albumScrollView];  
    _albumScrollView.delegate = self;  
      
    //添加PageControl  
    [self.view addSubview:self.albunPageControl];  
    //設置PageControl的頁數(shù)  
    _albunPageControl.numberOfPages = 3;  
      
    //給pageControl添加方法  
    [_albunPageControl addTarget:self action:@selector(pageControlChangeView:) forControlEvents:UIControlEventValueChanged];  
     
  
    //添加三張圖片  
    [self.photoArray addObject:[self addPhoto:CGRectMake(0, 0, WIDTH, HEIGHT) Image:[UIImage imageNamed:@"s1.png"]Tag:1000]];  
    [self.photoArray addObject:[self addPhoto:CGRectMake(WIDTH, 0, WIDTH, HEIGHT) Image:[UIImage imageNamed:@"s2.png"]Tag:1001]];  
    [self.photoArray addObject:[self addPhoto:CGRectMake(WIDTH*2, 0, WIDTH, HEIGHT) Image:[UIImage imageNamed:@"s3.png"]Tag:1002]];  
  
    //添加一張與第一張重復的圖片，制造循環(huán)效果  
    [self addPhoto:CGRectMake(WIDTH*3, 0, WIDTH, HEIGHT) Image:[UIImage imageNamed:@"s1.png"]Tag:1003];  
  
}  
  
//添加圖片函數(shù)  
-(UIScrollView*)addPhoto:(CGRect)frame Image:(UIImage*)image Tag:(NSInteger)tag  
{  
    //創(chuàng)建UIScrollView  
    UIScrollView *photoScrollView =[[UIScrollView alloc]initWithFrame:frame];  
    //創(chuàng)建UIimageView  
    UIImageView *photoImageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, WIDTH, HEIGHT)];  
    photoImageView.image = image;  
      
    //設置代理  
    photoScrollView.delegate = self;  
      
    //添加視圖縮放范圍，沒有這個縮放不了 找了半天。。。。。。。。。。。。。。。。。。。。。。。  
    photoScrollView.minimumZoomScale = 0.3;  
    photoScrollView.maximumZoomScale = 3;  
  
    //添加到父視圖  
    [photoScrollView addSubview:photoImageView];  
    [self.albumScrollView addSubview:photoScrollView];  
      
    return photoScrollView;  
}  
  
//pageControl點擊時進行滾動  
-(void)pageControlChangeView:(UIPageControl*)sender  
{  
    //根據(jù)頁數(shù)設置偏移量，加動畫  
    [_albumScrollView setContentOffset:CGPointMake(sender.currentPage*WIDTH, 0)animated:YES];  
}  
  
#pragma mark 代理  
  
//實現(xiàn)代理縮放方法  
-(UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView  
{  
  
    for (id item in scrollView.subviews) {  
        if ([item isKindOfClass:[UIImageView class]]) {  
            return item;  
        }  
    }  
    return nil;  
}  
  
//在左右拖拽時實現(xiàn)方法  
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView  
{  
      
//1.進行循環(huán)設置  
      
    //得到當前的偏移量  
    CGFloat offset_X = _albumScrollView.contentOffset.x;  
      
    //偏移到第四張之后，手動設置偏移量為0  
    if (offset_X >= WIDTH*3) {  
        _albumScrollView.contentOffset = CGPointMake(0, 0);  
        _albunPageControl.currentPage = 0;  
    }  
    else  
    {  
        //使PageControl與Scroll同步  
        _albunPageControl.currentPage = offset_X/WIDTH;  
    }  
      
    //在切換圖片的時候使照片恢復原來大小  
    //找到當前偏移值對應的數(shù)組index,但是向左右撥動又不一樣，有點麻煩  
    int index = (int)(offset_X/WIDTH)-1;  
    NSLog(@"index = %d",index);  
    // PhotoView *tempView = _photoArray[index];  
    //遍歷數(shù)組全修改了  
    for (UIScrollView *tempView in _photoArray) {  
        tempView.transform = CGAffineTransformMakeScale(1, 1);  
    }  
      
//2.進行縮放恢復設置  
      
    //根據(jù)偏移量得到當前page  
    int numPage = offset_X/WIDTH;  
      
    //用數(shù)組要考慮越界問題  
    if (numPage > 0 && numPage < 2) {  
        UIScrollView *leftScrollView = _photoArray[numPage-1];  
        UIScrollView *rightScrollView = _photoArray[numPage+1];  
        //恢復比例  
        leftScrollView.zoomScale = 1.0;  
        rightScrollView.zoomScale = 1.0;  
    }  
    else if (numPage == 0)  
    {  
        UIScrollView *rightScrollView = _photoArray[numPage+1];  
        rightScrollView.zoomScale = 1.0;  
    }  
    else if (numPage == 2)  
    {  
        UIScrollView *leftScrollView = _photoArray[numPage-1];  
        //恢復比例  
        leftScrollView.zoomScale = 1.0;  
    }  
}  
  
//縮放時保持圖片在中央  
-(void)scrollViewDidZoom:(UIScrollView *)scrollView  
{  
    UIImageView *myImageView = scrollView.subviews[0];  
    float contentX = scrollView.contentSize.width;  
    float contentY = scrollView.contentSize.height;  
      
    //如果放大沒有超出邊界  
    if (contentX < WIDTH && contentY <HEIGHT) {  
            myImageView.center = self.view.center;  
        NSLog(@"w = %f,h = %f",contentX,contentY);  
    }  
    else //如果放大超出了屏幕frame  
    {  
         
        myImageView.center = CGPointMake(contentX/2, contentY/2);  
    }  
    for (id item in scrollView.subviews) {  
        NSLog(@"zssm = %@",item);  
    }  
  
}  
  
@end  

實現(xiàn)效果：