Need UIImageView inside UIScrollView to change

[nenos]

Hey,

I have an UIImageView hooked up to the UIScrollView. All I want is to replace the image on the scrollview whenever a table cell is selected. So far what happens is that whenever I select a cell, the new image is added on top of the old image rather than replacing them.

Any help is appreciated.

[Lebowski]

So, what I'm guessing you are trying to do is to display an image that requires scrolling. The image displayed is based on user input in the form of a cell selection from a table view. If that is your intention, there is an excellent tutorial that sort of explains this. Here it is:

UITableView - Loading a detail view - iPhone SDK Articles

All you have to do display the image in a scrollview instead of an image view. You can also display it in the rootviewcontroller (which in this case is a tableview that already scrolls).

One of my applications does this and I found this tutorial very helpful. I hope this is what you need. Best of luck.

[nenos]

Hey Lebowski,

Thanks for the reply I already have the tableview all set, and the scrollview with an imageview inside of it. My problem is that whenever a different cell is selected, the image doesn't get replaced, but a new layer is added on top of the previous image. I'm working on the iPad's split view-based controller. Instead of adding a new layer of the image on top of the previous one, I want the image inside of the uiimageview to be replaced with the new image that is selected from the tableview cell.

This is what I have so far...

- (void)tableViewUITableView *)aTableView didSelectRowAtIndexPathNSIndexPath *)indexPath {

if (indexPath.section == 0) {
if (indexPath.row == 0) {
detailViewController.imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"1.png"]];
}
if (indexPath.row == 1) {
detailViewController.imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"1-2.png"]];
}
}

[Ice_2k]

You could try updating the image instead of creating a new image view:

detailViewController.imageView.image = [UIImage imageNamed .....];

[nenos]

Originally Posted by Ice_2k

You could try updating the image instead of creating a new image view:

detailViewController.imageView.image = [UIImage imageNamed .....];

Oh cool thanks Ice_2k, I still have one problem, scrollview doesn't scroll anymore, whereas before when I used the previous method, it did, and I have "[detailViewController.scrollView setScrollEnabled:YES];" but it doesn't scroll.

[Ice_2k]

There is a method that tells the scrollview how much it should scroll, setContentOffset is called I believe. Try calling this method with your desired scroll distance (the image height + whatever else you have on your view).

[nenos]

Originally Posted by Ice_2k

There is a method that tells the scrollview how much it should scroll, setContentOffset is called I believe. Try calling this method with your desired scroll distance (the image height + whatever else you have on your view).

Thanks Ice_2k, I tried that method but it still doesnt work lol

[Ice_2k]

Can you post the code you used to update the image?

[nenos]

Originally Posted by Ice_2k

Can you post the code you used to update the image?

Yeh sure, here it is...

if (indexPath.section == 0) {
if (indexPath.row == 0) {
detailViewController.imageView.image = [UIImage imageNamed:@"1.png"];
detailViewController.scrollView.clipsToBounds = NO;
detailViewController.scrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
[detailViewController.scrollView addSubview:detailViewController.imageView];
[detailViewController.scrollView setContentSize:CGSizeMake(detailViewController.ima geView.frame.size.width, detailViewController.imageView.frame.size.height)];
[detailViewController.scrollView setScrollEnabled:YES];

}
if (indexPath.row == 1) {
detailViewController.imageView.image = [UIImage imageNamed:@"1-2.png"];
detailViewController.scrollView.clipsToBounds = NO;
detailViewController.scrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
[detailViewController.scrollView addSubview:detailViewController.imageView];
[detailViewController.scrollView setContentSize:CGSizeMake(detailViewController.ima geView.frame.size.width, detailViewController.imageView.frame.size.height)];
[detailViewController.scrollView setScrollEnabled:YES];
}

}

[Ice_2k]

First of all, I'm not sure you should be using addSubView all the time. You should just add it in viewDidLoad (or in IB) and then just update its image. The way you're doing it, you're just adding the same view over and over again. I have no idea what side-effects that would have. Second, are you sure you're image view's size is updated along with the image? I think you should use the image's size and not the view's. Run this code in debug mode to figure out what the issue is:

int viewW = detailViewController.imageView.size.width;
int viewH = detailViewController.imageView.size.height;
int imageW = detailViewController.imageView.image.size.width;
int imageH = detailViewController.imageView.image.size.height;

If the height of the view is not the same as the height of the image, there's your problem.

[nenos]

Originally Posted by Ice_2k

First of all, I'm not sure you should be using addSubView all the time. You should just add it in viewDidLoad (or in IB) and then just update its image. The way you're doing it, you're just adding the same view over and over again. I have no idea what side-effects that would have. Second, are you sure you're image view's size is updated along with the image? I think you should use the image's size and not the view's. Run this code in debug mode to figure out what the issue is:

int viewW = detailViewController.imageView.size.width;
int viewH = detailViewController.imageView.size.height;
int imageW = detailViewController.imageView.image.size.width;
int imageH = detailViewController.imageView.image.size.height;

If the height of the view is not the same as the height of the image, there's your problem.

hey,

thanks for the reply.

1) I added the methods to the viewDidLoad and left the if's with the method of swapping the images

2) I have images which are really tall in height, and I want them to be like that, do they have to be the same height as the view? How do you use that code to check it?

Sorry I'm not a pro at xcode lol

[Ice_2k]

You set a breakpoint on the code I gave you and check the results as each statement is executed.

[themaccity]

I am in the same scenario, where I need the image in the imageView to change based on the cell, and I have this code in my didSelectRowAtIndexPath method:

if (indexPath.row == 0) {
detailViewController.imageView.image = [UIImage imageNamed:@"1.png"];

}

i don't have anything else because everything else is handled in my DetailViewController (e.g. scrollView.clipsToBounds, etc.)

however when I build the project I get an error that says "Request for member "imageView" in something not a structure or a union"

[Ice_2k]

Originally Posted by themaccity

I am in the same scenario, where I need the image in the imageView to change based on the cell, and I have this code in my didSelectRowAtIndexPath method:

if (indexPath.row == 0) {
detailViewController.imageView.image = [UIImage imageNamed:@"1.png"];

}

i don't have anything else because everything else is handled in my DetailViewController (e.g. scrollView.clipsToBounds, etc.)

however when I build the project I get an error that says "Request for member "imageView" in something not a structure or a union"

The compiler doesn't know who detailViewController is (or what type it is).