ScrollView of images in ios

问题:

Hi my requirement is showing image in scrollview along with that it should display next and previous button.User can scroll the image as well as use buttons to move images.

I have doubt about how to get the index/tag/imagename or anything else when user scroll based on that values buttons should be updated.

Here is my Code

[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;
    ...  

Array Initialisation method

-(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];
} 

Action Methods

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

scroll is working correctly but when user clicks on prev and next image is not updating on 'imageview'

Here is my updated code

    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);

       }  

回答1:

I have left and right button for scroll images, and imageview width is same.

I am writing code for scroll image at pressing button.

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];
    }
} 

Set scrollView Deleagte

Scroll View delegate Method

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
   pos=scrollView.contentOffset.x/scrollView.frame.size.width;
}

回答2:

You can use UIPageControl and set and get image according to page index. For more information check out this link

回答3:

Try below piece of code. I hope it will help. Put this in your .h file

IBOutlet UIScrollView *scrollView;
IBOutlet UIPageControl *pageControl;

NSMutableArray *arrImages;
NSInteger page;

Now in your - (void)viewDidLoad put following lines.

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;

implement scroll view delegate.

#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
        }
    }
 }