I'm currently developping iPad application with 2 UIScrollView in the same page.
On the left side, there is the content and on the right side, there are some bloc, news. These two UIScrollView are different height size.
Example : left 1000, right 2000.
I would like to synchronize the 2 UIScrollView, I explain me :
When the user scrolls on the left UIScrollView to access on the bottom, the right UIScrollView "scrolls" in the same time. If the left UIScrollView is happened to be at the bottom, and the right UIScrollView is NOT on the bottom, the right UIScrollView continue to scroll until ... it stop naturally.
And the same behavior if the user scroll on the right UIScrollView.
Do you have an idea how to resolve or to handle my problem ?
You have to listen to the delegate method of scrollViewDidScroll then you can set the contentOffset of the second UIScrollView.
I'll just post the solution I used in case anyone gets to this question in the future.
You don't set the contentOffset directly. You need to do a workaround. Like so:
CGRect viewToUpdateBounds = viewToUpdate.bounds;
viewToUpdateBounds.origin = scrolledView.contentOffset;
viewToUpdate.bounds = viewToUpdateBounds;
Regards
Related
I have a screen full of different UI objects that I need to scroll if on a 3.5 inch iPhone screen. I've added the ScrollView and setEnabled to YES but it still doesn't work. I'm thinking I should just code all the objects instead of using the IB and then add them to the scrollview. If I use a view with a scrollview on top with a view on top of that, then add them all to the subview, they lose their positioning. As for the constraints on the IB, there are simply too many objects and with hours spent on different constraint use, that will not be an option. Thanks for any suggestions and help.
Try to set the content size to be the size your frame, which is this case your view controller since you mentioned its "a screen full of different UI objects"
self.scrollView.contentSize = self.scrollView.frame.size;
then set scrollView frame to be the size of the view's frame
self.scrollView.frame = self.view.frame;
UIScrollView wont scroll, if the contents inside of the UIScrollview, are small enough to view without scrolling.
So if you have a UIView obj inside of your UIScrollView and that UIView is not Bigger than the UIScrollView, by default the UIScrollview will not scroll.
Description
If you use the Spotify app on iOS or Android (I am developing on iOS), you'll notice that if you select a playlist, and drag the UITableView with your songs up, the following happens:
The table doesn't scroll, it just moves up at the same speed it would scroll, and the images above it move slower than the table, creating a parallax scrolling effect.
Once the tableview reaches the top of the view, however, it behaves like a normal scrolling tableview.
I've tried to achieve this effect a few different ways, which didn't work for me.
Here is a video of this effect: https://www.dropbox.com/s/n7npk4lrzmag0sn/IMG_9331.MOV
What I tried
I wanted the UITableView and the UIScrollView above it, to move upwards when the user scrolled either one, so I used
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
and based on the direction of the scroll, I changed the frame position of the tableview and the UIScrollView above it.
The problem with this method is that the tableview bounces, which ruins the effect.
To get rid of bouncing, I tried the following:
_userTableView.bounces = NO;
However, now because the tableview wouldn't scroll, scrollViewDidScroll is never called.
The other thing I tried was subclassing the UITableView, and overriding the
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
hitTest method to detect a scroll gesture on the tableview, the problems with this are:
Only 1 CGPoint is passed -- it's impossible to know if the UITableView was touched, or scrolled.
Since scrolling is disabled, I can't use self.decelerating to check if the tableview was just scrolled -- the tableview will never be decelerating
Making the table decelerate as it moves up the view, and continue scrolling with the same momentum after its reached the top will be very challenging; In the Spotify app, a user can drag the table with a speed high enough to make the table view move to the top of the view AND continue scrolling, all in one motion.
The tableview should grow in size to accommodate more cells added to the view (without scrolling), as it moves up the view, or it should start out with the same size as the view. After it reaches the top it should begin scrolling like a normal tableview -- with the same momentum it has after the upward movement.
Any suggestions on how I can solve this?
Thank you very much.
For the effect you have shown, I think a tableHeaderView with the parallax content as a subview will suffice.
In -scrollViewDidScroll: (or KVO for contentOffset), you set the center of the parallax subview to the center of the visible bounds of the tableHeaderView. You can also adjust how much the content "sticks" to the center by multiplying a factor.
CGRect tableViewHeaderVisibleBounds = tableViewHeader.bounds;
tableViewHeaderVisibleBounds.origin.y = MAX(0, MIN(CGRectGetHeight(tableViewHeader.bounds), tableView.contentOffset.y));
tableViewHeaderVisibleBounds.size.height -= tableViewHeaderVisibleBounds.origin.y;
CGFloat factor = 1.8f; // less than 0.5:stick to top // greater than 0.5:stick to bottom
parallaxContentView.center = (CGPoint){
.x = parallaxContentView.center.x,
.y = (CGRectGetMinY(tableViewHeaderVisibleBounds)
+ (CGRectGetHeight(tableViewHeaderVisibleBounds) * factor))
};
I coded this inside my head so just make necessary adjustments, but I hope you get the basic idea.
Check this URL http://krystalrae.com/
Scrolling down you will see a girl's cloths are changing on mouse wheel scrolling.
I have to create a iPad application where 3 images will appear likewise. The difference will be that in my case image change will occur horizontally rather than vertically in website. Also, i have to make it inside UIView with events touchesBegan, touchesMoved, touchesEnded and touchesCancelled
Help will be appreciated.
Thanks.
From your comment I gather that the problem is the resizing of the images in UIImageView when changing the bounds of the view.
You can set the contentMode of the image view to something else. The default is UIViewContentModeScaleToFill which is not what you want.
You could, for example, set the lower image view to UIViewContentModeBottom, and the upper image view to UIViewContentModeTop.
Don't forget to make sure your image views have sett the property maskToBounds set as YES.
I've built an app using the UITabBar template. I have a few tabbar items, one item displays a view. That view has a UIScrollView element that has paging enabled to mimic the behaviour of the iPhone springboard i.e. pages that can be scrolled left to right.
I'm trying to drop in a UIPageControl, so I've resize the UIScrollView so that it's slightly shorter than the parent UIView height and have placed a UIPageControl below it.
When I run the app the UIScrollView is always 100% of the height of the parent UIView and I can't see the UIPageControl.
I've got the following code in my viewDidLoad method of the view controller for the tab:
UIScrollView *tempScrollView=(UIScrollView *)self.view;
tempScrollView.contentSize=CGSizeMake(640,377);
This sets the content size ok and I can scroll left to right. I've tried adding:
tempScrollView.frame=CGRectMake(0, 0, 640, 377);
To to resize the scroll view but it still shows 100%. See diagram below showing the issue:
I think you shouldn't resize the frame to 640, 377 because it would make the paging stop working, once the contentSize would be the same as the frame size.
One solution would be to set the desired frame size in the interface builder (like the left most figure) and set proper autosizing masks. I gues what you are looking for is the configuration below
To check if the changes are working, I would use a uiscrollview of height visibly smaller, just to make sure the behaviour is the desired.
If you want your view to scroll you need to change the tempScrollView.contentSize to be bigger than tempScrollView.frame
If you do this:
CGFloat contentWidth = tempScrollView.frame.size.width*2;
tempScrollView.contentSize=CGSizeMake(contentWidth,377);
You will have 2 pages.
You need to activate paging too with:
[tempScrollView setPagingEnabled:TRUE];
I have a NSScrollView with a custom view inside and when I resize the NSScrollView, the height grows and it scrolls upward. Unless there is an easier way, I'll probably have to register a notification to see if the view changes size and then adjust the scrollPoint: to a new point. I'm having trouble getting method to work smoothly.
Thanks!
This question comes up from time to time, because it's not obvious.
The content will pin to the top left if [contentView isFlipped] == YES.