In a ViewController, there are three tableViews in a scrollView:
when the segment[1] tapped scrollView scroll to the second tableView, and the segment[2] tapped scrollView scroll to the third tableView
the problem is, if the second tableView is displayed now, when call [self.navigationController pushViewController:viewController animated:YES];, the scrollView auto display the first tableView,but its contentOffset is still {320,height}
Related
I have already built out 2 collection views, 1 horizontally scrolling (at the top) & 1 vertically scrolling (at the middle - bottom) that are used to view 2 different sets of content in my Objective-C iOS application similar to this Instagram screenshot:
I am trying to add functionality to make it so that the horizontally scrolling Collection View disappears when the user scrolls up on the vertically scrolling one. What is the best way to accomplish this task? I have looked up tutorials on adding a collection view in another collection view's cell but I cant find anything on just adding a collection view to the 1st cell of another collection view. What would be the best way to accomplish this functionality?
I think you should you use UITableView with UICollectionView. On the screeshot, I think horizontal collectionview is embedded in first cell of the tableview. And when use starts to scroll tableview, first row is gone as you want.
Edit
Create uitableview with 2 prototype cells. Create horizontall collectionview and embed it in first cell of tableview, this is first prototype cell. Then create second prototype cell for images. And when user will start scroll the tableview first cell will gone, as you want.
If you don't want to go with the other suggested method of embedding the horizontal collection view into the top cell of the vertical collection view, you could use the vertical collection view's scrolling callbacks (scrollViewDidScroll, since UICollectionView subclasses UIScrollView). When the vertical collection view scrolls, you can apply a transform to the top collection view to move it off the top of the screen based on the contentOffset of the vertical collection view, and then have it reappear once the contentOffset approaches 0.
Keep in mind that with this approach, the vertical collection view's frame will likely be the height of the screen minus the height of the horizontal collection view. Therefore, you will need a bit of extra logic to expand the vertical collection view's frame to take up the whole screen once the horizontal collection view has disappeared from sight. Otherwise, you will have an awkward blank bar at the top of the screen where the horizontal collection view initially was while you scroll.
You have two scroll view lets call it "cvHorizontal" and "cvVertical".
You can manage scrollViewDidScroll method to hide cvHorizontal when scrolled up and show cvHorizontal when scrolled down.
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
if (lastContentOffset > scrollView.contentOffset.y){
[self showCategory:YES];
lastContentOffset = scrollView.contentOffset.y;
} else if (lastContentOffset < scrollView.contentOffset.y) {
[self showCategory:NO];
lastContentOffset = scrollView.contentOffset.y;
}
}
-(void)showCategory:(BOOL)flag{
if(flag){
[UIView animateWithDuration:0.6 animations:^{
if(cvHorizontal.hidden ){
cvHorizontal.hidden=NO;
cvHorizontalHeight.constant=65.0f;//manage the cvHorizontal height and all the other constraints calculation if any
}
}];
}else {
[UIView animateWithDuration:0.6 animations:^{
cvHorizontal.hidden=YES;
cvHorizontalHeight.constant=0;
}];
}
}
I have ViewController that have a UIView view and a TableView table inside it. View has big height so i want to hide it when user starts to scroll table - so table is now taking the whole screen.
To do that I use this method.
func scrollViewWillBeginDragging(scrollView: UIScrollView) {
//hide view or decrease it height
}
I hide view with animation - so it takes few moments to hide. The problem is - when user start to scroll table and view is begin to become smaller - some of top cells of table are already not showing because they are in top.
I want to pause scrolling - so that it can begin only after the view height is decreased. Also - I am afraid that it can be strange for users.
You need to make the height change as per user scroll to make it efficient.
override another delegate function
func scrollViewDidScroll(_ scrollView: UIScrollView) {
myView.heightConstraint = myView.originalHeight - scrollView.contentOffset.y;
}
The contentOffset property gives you the current amount of x,y scrolled in the scrollview from the origin.
What you can do is, you can give your tableView the entire screen and make another view with whatever height you want and make it as a header view of your tableView. So now the view will scroll as your tableView scrolls. Is this what you are looking for?
[tableView setHeaderView:<your-custom-header-view>];
I have the following view structure, the root view is UIScrollView, UIScrollView has two subViews, it is a UIView, the following is a scrollView, set contentSize scrollView for the content view size, I want to be contentOffset.y scrollView view.height when the current sliding event transfer to the following tableView to continue processing, so that tableView and scrollView continue to slide
You could catch each scroll event from your scroll view using this delegate method
- scrollViewDidScroll:
and then apply same content offset to the table view.
I have an UIPagerView with its View Controllers. Each UIViewController have an horizontal UIScrollView (with 3 horizontal images, for example). See the image for reference.
When i do a horizontal swipe gesture on the scrollview, the scrollview scrolls and the pagerview doesnt. When i do a horizontal swipe gesture in any view that is not the scrollview, the pagerview scrolls its child view controllers. Everything is fine by now.
What i want to achieve is: when i scroll the scrollview to the max value (its contentSize), i want the pagerview to scroll its viewcontrollers.
Please, how can i achieve this??
To achieve what you have described, you need to set the pagerViewController as a delegate of your ScrollView.
Assuming that your ScrollView is a PageViewController, first make PagerViewController a PageViewControllerDelegate
#interface PagerViewController: UIViewController <UIPageViewControllerDelegate>
Then set the PagerViewController as the delegate of your ScrollView. Do this in viewDidLoad() method of PagerViewController
-(void) viewDidLoad
{
//some other stuff
self.scrollView.delegate = self
}
then implement didFinishAnimating delegate method in PagerViewController. It will be called whenever you scroll your scrollView controller, and you can figure out if its the last page you just scrolled by looking at the index of the latest controller. If it is, then trigger the code to scroll the PagerViewController to scroll on to the next view.
I currently have a view controller that is comprised of a Navigation bar, followed by a UIView that has two UIButtons added as subViews. There is then a UITableView underneath that begins at the bottom of the container UIView.
At the moment, when the user scrolls the UITableView it goes behind the UIView and UIButtons. What I actually want to happen is for the UIView and UIButtons to move up with the table view but only by the value of their height which in this case is 58 pixels. The flow would be like this...
1) Table scrolls and the UIView moves with it for the first 58 pixels.
2) The user continues to scroll the table but the UIView "pins" itself just out of view under the navigation bar.
3) When the user scrolls the table back down the UIView is then picked up and dragged back into view. I believe the new Facebook app does something similar in the timeline.
I don't want to set the UIView as the TableHeaderView of the table as I also have a pull-to-refresh which then sits above the buttons and looks terrible. I've tried playing around with the contentOffset properties of the underlying scrollview of the table but have hit a brick wall.
Any advice on where to start would be appreciated.
Thanks
EDIT: I am gotten a little further and using this code to move the frame of the UIView.
-(void) scrollViewDidScroll:(UIScrollView *)scrollView
{
NSLog (#"Content Offset: %f", self.tableView.contentOffset.y);
NSLog (#"Button Frame: %f", self.btnBackground.frame.origin.y);
if (self.tableView.contentOffset.y > 0)
{
CGRect newFrame = self.btnBackground.frame;
newFrame.origin.x = 0;
newFrame.origin.y = -self.tableView.contentOffset.y;
[self.btnBackground setFrame: newFrame];
}
}
The problem now is that the scrollViewDidScroll delegate method doesn't get fired quickly enough if the table view is scrolled fast. The result is that the UIView doesn't quite make all way back to its original position when scroll quickly.
The scroll content offset is a good idea. Also if you tableview has only one section one approach is to do a custom header view representing the top level widgets. If there is more than one sections create an additional empty section which would return your custom header.
You can refer to this stack overflow post.
Customize UITableview Header Section
Well Asked Question (y)
well , for me i would first : use a main UIScrollView that contains both your topView and the tableView under it and that has the same width as your top UIView and UITableView and set its height to be height(tableView) + height(topView).
Second : since UITableView is a subClass of UISCrollView you can use scrollViewDidScroll delegate to know if the tableview is scrolled up or down.
in this cas you will have Two cases :
1) tableview is scrolled up = > you set the content offset of the main scrollView to be
[scrollView setContentOffset:CGPointMake(0, 58) animated:YES];
2) when the table view is scrolled down you can reset the content offset again
[scrollView setContentOffset:CGPointMake(0, 0) animated:YES];