How to change the label text in UIScrollview for each page Different text?

问题

Hi in my app i want to show label text different at each image in UIScrollView. Here is my code.

for (int i=0; i<imageArray.count; i++)
{
    NSString *str = [imageArray objectAtIndex:i];
    NSString *bannerImageURL = [NSString stringWithFormat:@"http://url.com", str];
    CGFloat myOrigin = i * self.view.frame.size.width;

 UIImageView *myImageView = [[UIImageView alloc] initWithFrame:CGRectMake(myOrigin, 0, self.view.frame.size.width,imgScrollView.frame.size.height)];
    myImageView.contentMode = UIViewContentModeScaleToFill;
    myImageView.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:bannerImageURL]]];
 imgScrollView.contentSize = CGSizeMake(self.view.frame.size.width * imageArray.count,                                      self.view.frame.size.height);

CGPoint scrollPoint = CGPointMake(0, 0);
[imgScrollView setContentOffset:scrollPoint animated:YES];
imgScrollView.delegate = self;
[imgScrollView addSubview:myImageView];
}

Here is my Delegate Methods.

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
 {
  [imgScrollView setContentOffset: CGPointMake(imgScrollView.contentOffset.x,0)];
 }
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
CGFloat pageWidth = scrollView.frame.size.width;
int page = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
NSLog(@"Scrolling - You are now on page %i",page);
}

I want to pass an array to that label and one more thing how to add page controller to this code? Please Help.

回答1:

I'm not really sure what label you are referring to in the above question. I'll assume you have a label UILabel * _label and an array NSArray * _namesArray defined in your header.

I've tried to clean up your code a little bit. Try this:

for(int index = 0; index < [imageArray count]; index++){
  NSString * string = [imageArray objectAtIndex:index];
  NSString * bannerImageURL = [NSString stringWithFormat:@"http://url.com/%@", string]; // You weren't using the string in your formatter, so I added it to the end.
  CGFloat myOrigin = index * self.view.frame.size.width;

  UIImageView * myImageView = [[UIImageView alloc] initWithFrame:CGRectMake(myOrigin, 0.0f, self.view.frame.size.width, imageScrollView.frame.size.height)];
  myImageView.contentMode = UIViewContentModeScaleToFill;
  myImageView.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:bannerImageURL]]];
  [imageScrollView addSubview:myImageView];
}
imageScrollView.contentSize = CGSizeMake(self.view.frame.size.width * imageArray.count,                                      self.view.frame.size.height);
[imageScrollView setContentOffset:CGPointZero animated:YES];
imageScrollView.delegate = self;

Then for the delegate methods, you'll want to try:

- (void)scrollViewDidScroll:(UIScrollView *)scrollView; {
  CGFloat pageWidth = scrollView.frame.size.width;
  int page = floor((scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;
  _label.text = [_namesArray objectAtIndex:page];
  NSLog(@"Scrolling - You are now on page %i, and the name for the label is: %@", page, [_namesArray objectAtIndex:page]);
}

Hope that Helps!

来源：https://stackoverflow.com/questions/37067853/how-to-change-the-label-text-in-uiscrollview-for-each-page-different-text