iOS学习笔记——滚动视图（scrollView）

Posted 2020-07-30 roucheng

滚动视图：在根视图中添加UIScrollViewDelegate协议，声明一些对象属性

@interface BoViewController : UIViewController<UIScrollViewDelegate>  
//滚动视图对象  
@property (retain, nonatomic) UIScrollView *scrollView;  
//视图中小圆点，对应视图的页码  
@property (retain, nonatomic) UIPageControl *pageControl;  
//动态数组对象，存储图片  
@property (retain, nonatomic) NSMutableArray *images;  
@end  
/* 何问起 hovertree.com */

在程序中导入图片，在.m文件中的代码实现：

- (void)viewDidLoad  
{  
    [super viewDidLoad];  
    //初始化scrollView  
    self.scrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0, 0, 320, 345)];  
    //初始化pageControl  
    self.pageControl = [[UIPageControl alloc]initWithFrame:CGRectMake(0, 344, 320, 36)];  
    //初始化数组，存储滚动视图的图片  
    self.images = [NSMutableArray arrayWithObjects:[UIImage imageNamed:@"text1.png"],[UIImage imageNamed:@"text2.png"],[UIImage imageNamed:@"text3.png"],[UIImage imageNamed:@"text4.png"], nil nil];  
    //把scrollView与pageControl添加到当前视图中  
    [self.view addSubview:self.scrollView];  
    [self.view addSubview:self.pageControl];  
    //设置视图的背景颜色  
    self.view.backgroundColor = [UIColor blackColor];  
    //调用 setuoPage方法  
    [self setupPage:nil];     
}  
//改变滚动视图的方法实现  
- (void)setupPage:(id)sender  
{  
    //设置委托  
    self.scrollView.delegate = self;  
    //设置背景颜色  
    self.scrollView.backgroundColor = [UIColor blackColor];  
    //设置取消触摸  
    self.scrollView.canCancelContentTouches = NO;  
    //设置滚动条类型  
    self.scrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;  
    //是否自动裁切超出部分  
    self.scrollView.clipsToBounds = YES;  
    //设置是否可以缩放  
    self.scrollView.scrollEnabled = YES;  
    //设置是否可以进行画面切换  
    self.scrollView.pagingEnabled = YES;  
    //设置在拖拽的时候是否锁定其在水平或者垂直的方向  
    self.scrollView.directionalLockEnabled = NO;  
    //隐藏滚动条设置（水平、跟垂直方向）  
    self.scrollView.alwaysBounceHorizontal = NO;  
    self.scrollView.alwaysBounceVertical = NO;  
    self.scrollView.showsHorizontalScrollIndicator = NO;  
    self.scrollView.showsVerticalScrollIndicator = NO;  
    //用来记录页数  
    NSUInteger pages = 0;  
    //用来记录scrollView的x坐标  
    int originX = 0;      
    for(UIImage *image in self.images)  
    {  
        //创建一个视图  
        UIImageView *pImageView = [[[UIImageView alloc]initWithFrame:CGRectZero]autorelease];  
        //设置视图的背景色  
        pImageView.backgroundColor = [UIColor colorWithRed:0.6 green:0.6 blue:0.6 alpha:1.0];  
        //设置imageView的背景图  
        [pImageView setImage:image];  
        //给imageView设置区域  
        CGRect rect = self.scrollView.frame;  
        rect.origin.x = originX;  
        rect.origin.y = 0;  
        rect.size.width = self.scrollView.frame.size.width;  
        rect.size.height = self.scrollView.frame.size.height;  
        pImageView.frame = rect;  
        //设置图片内容的显示模式(自适应模式)  
        pImageView.contentMode = UIViewContentModeScaleAspectFill;  
        //把视图添加到当前的滚动视图中  
        [self.scrollView addSubview:pImageView];  
        //下一张视图的x坐标:offset为:self.scrollView.frame.size.width.  
        originX += self.scrollView.frame.size.width;  
        //记录scrollView内imageView的个数  
        pages++;  
    }  
    //设置页码控制器的响应方法  
    [self.pageControl addTarget:self action:@selector(changePage:) forControlEvents:UIControlEventValueChanged];  
    //设置总页数  
    self.pageControl.numberOfPages = pages;  
    //默认当前页为第一页  
    self.pageControl.currentPage = 0;  
    //为页码控制器设置标签  
    self.pageControl.tag = 110;  
    //设置滚动视图的位置  
    [self.scrollView setContentSize:CGSizeMake(originX, self.scrollView.bounds.size.height)];      
}  
//改变页码的方法实现  
- (void)changePage:(id)sender  
{  
    NSLog(@"指示器的当前索引值为:%i",self.pageControl.currentPage);  
    //获取当前视图的页码  
    CGRect rect = self.scrollView.frame;  
    //设置视图的横坐标，一幅图为320*460，横坐标一次增加或减少320像素  
    rect.origin.x = self.pageControl.currentPage * self.scrollView.frame.size.width;  
    //设置视图纵坐标为0  
    rect.origin.y = 0;  
    //scrollView可视区域  
    [self.scrollView scrollRectToVisible:rect animated:YES];      
}  
#pragma mark-----UIScrollViewDelegate---------  
//实现协议UIScrollViewDelegate的方法，必须实现的  
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView  
{  
    //获取当前视图的宽度  
    CGFloat pageWith = scrollView.frame.size.width;  
    //根据scrolView的左右滑动,对pageCotrol的当前指示器进行切换(设置currentPage)  
    int page = floor((scrollView.contentOffset.x - pageWith/2)/pageWith)+1;  
    //切换改变页码，小圆点  
    self.pageControl.currentPage = page;  
}  
  
- (void)didReceiveMemoryWarning  
{  
    [super didReceiveMemoryWarning];  
    // Dispose of any resources that can be recreated.  
}  
//释放创建的对象  
- (void)dealloc  
{  
    [_pageControl release];  
    [_scrollView release];  
    [super dealloc];  
}  /* 何问起 hovertree.com */

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