ios中图像的ScrollView

Posted 2023-03-16

【中文标题】ios中图像的ScrollView

【英文标题】：ScrollView of images in ios

【发布时间】：2014-05-12 06:52:11

【问题描述】：

您好，我的要求是在scrollview 中显示图像，并显示下一个和上一个按钮。用户可以滚动图像以及使用按钮移动图片。

我对如何获取index/tag/imagename 或当用户滚动基于该值的按钮应该更新时的任何其他内容存有疑问。

这是我的代码

[self arrayInitiaisation];  
scrollview.pagingEnabled = YES;
scrollview.alwaysBounceVertical = NO;
scrollview.alwaysBounceHorizontal = YES;
NSInteger numberOfViews = 4;

for (int i = 0; i < numberOfViews; i++) 

    CGFloat xOrigin = i*320;
    imageView.image = [UIImage imageNamed:[NSString stringWithFormat:@"image%d",i+1]];
    imageView.contentMode = UIViewContentModeScaleAspectFit;
    [self.scrollview addSubview:imageView];
    imageView.tag = i;
    ...  

数组初始化方法

-(void) arrayInitialisation 

  count=0;
  [super viewDidLoad];
  images=[NSMutableArray arrayWithObjects : [UIImage imageNamed:@"image1.png"],
    [UIImage imageNamed :@"image2.png"],
    [UIImage imageNamed :@"image3.png"],
    [UIImage imageNamed :@"image4.png"],nil];
    [imageView setImage:[images objectAtIndex:0]];
    NSLog(@"Array Length :%d",images.count);
    [previous setEnabled:NO];
 

动作方法

- (IBAction)nextButton:(id)sender 
- (IBAction)prevButton:(id)sender 

滚动工作正常，但是当用户点击 prev 并且 next 图像没有在 'imageview' 上更新

这是我更新的代码

    int count=0;

    - (void)viewDidLoad
    
    [super viewDidLoad];
    [self arrayInitialisation];
    [scrollview setScrollEnabled:YES];
    self.scrollview =[[UIScrollView alloc] initWithFrame:CGRectMake(30 , 30, 320, 412)];
    self.scrollview.delegate=self;
    scrollview.pagingEnabled = YES;
    scrollview.alwaysBounceVertical=NO;
    scrollview.alwaysBounceHorizontal=YES;
    scrollview.showsHorizontalScrollIndicator=NO;
    NSInteger numberOfViews = 4;
    for (int i = 0; i < numberOfViews; i++) 
    CGFloat xOrigin = i*320;
    imageView = [[UIImageView alloc]initWithFrame:CGRectMake(xOrigin, 0, 320, 412)];
    imageView.image = [images objectAtIndex:i];
    imageView.contentMode = UIViewContentModeScaleAspectFit;
    [self.scrollview addSubview:imageView];
    imageView.tag=i;




scrollview.contentSize = CGSizeMake(320*numberOfViews, 412);
scrollview.contentOffset = CGPointMake(0,0);
[self.view addSubview:self.scrollview];


    - (void)didReceiveMemoryWarning
      
         [super didReceiveMemoryWarning];
         
      -(void) arrayInitialisation
       count=0;
        [super viewDidLoad];
       images=[NSArray arrayWithObjects :  [UIImage imageNamed:@"image1.png"],
        [UIImage imageNamed :@"image2.png"],
        [UIImage imageNamed :@"image3.png"],
        [UIImage imageNamed :@"image4.png"],nil];
     [imageView setImage:[images objectAtIndex:0]];
     NSLog(@"Array Length :%d",images.count);
    [previous setEnabled:NO];
    


   - (IBAction)nextButton:(id)sender 
    if(count==0)
    count++;
    NSLog(@"Next Button : if Loop %d",count);
    [imageView setImage:[images objectAtIndex:count]];
    [previous setEnabled:YES];

      
       else

    [previous setEnabled:YES];
    count++;
     NSLog(@"Next Button : else Loop %d",count);
    if(count <images.count)
        [imageView setImage:[images objectAtIndex:count]];
    
    else
        [next setEnabled:NO];

    
    

     

      - (IBAction)prevButton:(id)sender 
       if(count==0)
      //count--;
       NSLog(@"prev Button : if Loop %d",count);
     [imageView setImage:[images objectAtIndex:count]];
     [previous setEnabled:NO];
    [next setEnabled:YES];
    
    else
    count--;
     NSLog(@"prev Button : else Loop %d",count);
    [imageView setImage:[images objectAtIndex:count]];
    [previous setEnabled:YES];
    //[next setEnabled:YES];
   
  
    #pragma mark - ScrollView Delegate

    - (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:    (BOOL)decelerate
    //NSLog(@"scrollViewDidEndDragging");
    /* count=count+1;
    NSLog(@"scrollViewDidEndDragging : %d",count);*/
   
    - (void)scrollViewDidScroll:(UIScrollView *)scrollView
    //NSLog(@"scrollViewDidScroll");

    
     - (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset NS_AVAILABLE_ios(5_0)
    //NSLog(@"scrollViewWillEndDragging");
    count=count+1;
    NSLog(@"scrollViewWillEndDragging : %d",count);

         

【问题讨论】：

github.com/nicklockwood/iCarousel

感谢@Waki 的链接

【参考方案1】：

我有滚动图像的左右按钮，并且图像视图宽度相同。

我正在编写按下按钮时滚动图像的代码。

int pos=0;// ViewDiaLoad

- (IBAction)OnClickLeftButton:(UIButton*)sender

    if(pos>0)
    
        pos -=1;
        [scrlDemandMenu scrollRectToVisible:CGRectMake(pos*scrlDemandMenu.frame.size.width, 0, scrlDemandMenu.frame.size.width, scrlDemandMenu.frame.size.height) animated:YES];

    


- (IBAction)OnClickRightButton:(UIButton*)sender

    if(pos<numberOfImages)
    
        pos +=1;
        [scrlDemandMenu scrollRectToVisible:CGRectMake(pos*scrlDemandMenu.frame.size.width, 0, scrlDemandMenu.frame.size.width, scrlDemandMenu.frame.size.height) animated:YES];
    
 

设置滚动视图委托

滚动视图委托方法

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView

   pos=scrollView.contentOffset.x/scrollView.frame.size.width;

【讨论】：

谢谢。我的问题已经解决了。@Bipin Patel

【参考方案2】：

您可以使用 UIPageControl 并根据页面索引设置和获取图像。欲了解更多信息，请查看此link

【讨论】：

我的要求是只使用按钮来导航图像。 @Satyarth Kumar Prasad

图片滚动时如何获取contentOffset。我需要计算图片是从左到右滚动还是从左到右滚动。

- (void)scrollViewDidEndDecelerating:(UIScrollView *)sender uint page = sender.contentOffset.x / width; [self.pageControl setCurrentPage:page];

【参考方案3】：

试试下面的代码。我希望它会有所帮助。把它放在你的 .h 文件中

IBOutlet UIScrollView *scrollView;
IBOutlet UIPageControl *pageControl;

NSMutableArray *arrImages;
NSInteger page;

现在在您的 - (void)viewDidLoad 中添加以下几行。

int x = 30;
for (int i=0; i< arrImages.count; i++)

    UIImageView *imgShow = [[UIImageView alloc]initWithFrame:CGRectMake(x+20, 50, self.view.frame.size.width-100, self.view.frame.size.height-180)];
    imgShow.backgroundColor = [UIColor whiteColor];
    imgShow.image = [UIImage imageNamed:[arrImages objectAtIndex:i]];
    imgShow.contentMode = UIViewContentModeScaleAspectFit;
    [scrollView addSubview:imgShow];

    x = x+scrollView.frame.size.width;

scrollView.contentSize = CGSizeMake(5*self.view.frame.size.width, 0);

pageControl.backgroundColor = [UIColor clearColor];
pageControl.pageIndicatorTintColor = [UIColor grayColor];
pageControl.currentPageIndicatorTintColor = [UIColor blueColor];
[pageControl setTintAdjustmentMode:UIViewTintAdjustmentModeDimmed];
pageControl.numberOfPages = arrTitle.count;
pageControl.currentPage = 0;

实现滚动视图代理。

#pragma mark - ScrollView Delegate

- (void)scrollViewDidScroll:(UIScrollView *)scrollView1

    CGFloat pageWidth = scrollView.frame.size.width;
    float fractionalPage = scrollView.contentOffset.x / pageWidth;
    page = lround(fractionalPage);
    pageControl.currentPage = page;


- (IBAction)prevButton:(UIButton *)sender

    page = page-1;

    UIButton *btn = (UIButton *)[sender viewWithTag:sender.tag];
    // write your code

    for (id obj in btn.subviews)
   
        if ([obj isKindOfClass:[UIImageView class]])
        
            // write your code
        
        else
        
            // write your code
        
    


- (IBAction)nextButton:(UIButton *)sender

    page = page+1;

    UIButton *btn = (UIButton *)[sender viewWithTag:sender.tag];
    // write your code

    for (id obj in btn.subviews)
    
        if ([obj isKindOfClass:[UIImageView class]])
        
            // write your code
        
        else
        
            // write your code
        
    
 

【讨论】：

如何使用 contentOffset

更改 scroview 中的图像