Is it possible to recognise gesture from scrollView so when one scrollView is dragged to simulate same dragging on another scrollView? For example I have tableView with custom cell that have scrollView in it, and I want to simulate dragging on every item in list.
EDIT
I succeeded to recognize movement of scrollView, but now I cant set other scrollViews from table to do same amount of scrolling.
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
int position_x = scrollView.contentOffset.x;
int i=0;
int indexPath = [self.tableView indexPathForSelectedRow].row;
static NSString *hlCellID = #"EPGCell";
UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:hlCellID];
UIScrollView *scrollView = (UIScrollView *)[cell viewWithTag:16];
for(i=0; i<EPGList.count;i++){
if(i!=indexPath){
scrollView.contentOffset = CGPointMake(position_x, scrollView.frame.size.height);
}
}
}
Problem is that indexPath is not returning correct value when i am clicking on scrollView. It returns correct value only when I am clicking on cell space outside of scrollview.
Yes, yes it is possible. You need to have a delegate assigned to the scrollViews within the cells. Preferrably the same class that implements hour tableview data source and table view delegate protocols. You must implement UIScrollViewDelegate and the delegate must implement the scrollViewDidScroll: method.
Within that scrollViewDidScroll delegate method, you check the contentOffset property for its x and/or y values. Normally people go for the vertical scrolling value, but if you're implementing them in a UITableViewCell, you're probably doing horizontal scrolling.
The you use the value, I am assuming contentOffset.x, to update other scroll views within the other cells of your table! Make sense?
I have just posted an answer to another UIScrollView question yesterday. Please read what I wrote there, it might help you more.
Animation in UIScrollView iOS app
Related
I have a UICollectionView with 1 row 1 column. I want to get the first item (indexPath basically) when I am scrolling it horizontally.
For example, I have got 100 items displayed horizontally in my UICollectionView and when I scroll from right to left, whichever item is the first one visible, I need its indexPath.
Which means the indexPath will be constantly changing while its scrolling.
How to achieve this? Please Guide. Thanks!
collectionView.indexPathsForVisibleItems() returns an array of NSIndexPath for visible cells. You can get the left most one by sorting them by NSIndexPath.item.
Edti:
To be notified while scrolling, implement the UIScrollViewDelegate method scrollViewDidScroll(_: UIScrollView). Remember that UICollectionView is a subclass of UIScrollView.
I think you need implement UIScrollView delegate method and get visible cell inside
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView{
UICollectionViewCell *firstCell = [[collectionView visibleCells] firstObject];
NSIndexPath *firstIndexPath = [collectionView indexPathForCell: firstCell];
NSLog(#"%#", firstIndexPath);
}
Hope this help
There is a button at the bottom of my view controller. When the user scrolls down the button has to be attached to the scrollview at certain height.
I need to attach a button to the scrollview, immediately when the contentOffset.y reaches a particular value. -(void) scrollviewDidScroll doesn't help me as there might be a jump in contentOffset when the user is scrolling fast. Any leads on this are helpful.
Also, whenever I add a subview to the scrollview, -(void) viewDidLayoutSubviews is called. Which in turn sets the contentOffset to {0,0}. How can I achieve the functionality I need?
I needed to do the same thing with a UITableView and for me using scrollViewDidScroll worked.
I created a view called staticBar and added it as a subview of the tableView, but I had to rearrange the tableview subviews for it to appear in the right place. I don't have my code in front of me, but in -scrollViewDidScroll: it looked something like this:
- (void)scrollViewDidScroll:(UIScrollView*)scrollView
{
CGFloat staticBarAdjustedY = _staticBarY - scrollView.contentOffset.y;
CGFloat scrollViewYFloor = scrollView.frame.size.height - _staticBar.frame.size.height;
// This way maximum Y the view can have is at the base of the scrollView
CGFloat newY = MIN( staticBarAdjustedY, scrollViewYFloor);
_staticBar.frame = (CGRect){ { _staticBar.frame.origin.x, newY}, _staticBar.frame.size}
}
I will check my code later today and add more details here.
Also, you said the scrollviewDidScroll has jumps in contentOffset, but it's worth mentioning that these jumps are the same that the scrollView uses to scroll its own view. So it's not like you are "losing" frames on this delegate method.
Hope it helps.
PS: So, here is the rest of my code.
//I place my custom view as a subview of the tableView below it's last subview
//The last subview is for scroll indicators.
WTButtonsBar *buttonBar = [[WTButtonsBar alloc] init];
[self.tableView insertSubview:buttonBar belowSubview:self.tableView.subviews.lastObject];
In scrollViewDidScroll:
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
//In my app I needed my view to stick to the top of the screen
//thats why I use MAX here
//self.buttonsBarOriginalY is the view's position in the scrollView when it isn't attached to the top.
CGFloat newY = MAX(scrollView.contentOffset.y, self.buttonsBarOriginalY)
[_buttonsBar setFrame:(CGRect){{0, newY}, _buttonsBar.frame.size}];
}
I need to get an array of all the subviews in a UIScrollView. Right now I'm using
NSArray *subviews = [myScrollView subviews];
but this seems to only be returning the subviews that are visible at the time the code is run. I need all the subviews in the whole extent of the UIScrollView, even those that are currently hidden (as in off screen). How would I get that?
Essentially, I'm looking for something like the contentSize property of a UIScrollView, except instead of returning just the size of the UIScrollView if it were big enough to display all of it's content, I want it to return the content itself.
EDIT: I think I've figured it out: the scroll view this isn't working for is actually a UITableView - and I think it's deque-ing the cells that are off screen on me, and that's why they aren't showing up. I'm going to do some testing to confirm.
Try with following code its working for me.
for(UIView * subView in myScrollView.subviews ) // here write Name of you ScrollView.
{
// Here You can Get all subViews of your myScrollView.
// But For Check subview is specific UIClass such like label, button, textFiled etc.. write following code (here checking for example UILabel class).
if([subView isKindOfClass:[UILabel class]]) // Check is SubView Class Is UILabel class?
{
// You can write code here for your UILabel;
}
}
tl;dr
It turns out that
NSArray *subviews = [myScrollView subviews];
will indeed return all the subviews in a UIScrollView *myScrollView, even if they are off-screen.
The Details
The problem I was actually having was that the scroll view I was trying to use this on was actually a UITableView, and when a UITableViewCell in a UITableView goes off-screen, it actually gets removed from the UITableView - so by the time I was calling subviews, the cells I was looking for were no longer in the scroll view.
My workaround was to build all of my UITableViewCells in a separate method called by my viewDidLoad, then put all of those cells into an array. Then, instead of using subviews, I just used that array. Of course, doing it this way hurts the performance a little (in cellForRowAtIndexPath you just return the cell from the array, which is slower than the dequeueReusableCellWithIdentifier method that is typically used), but it was the only way I could find to get the behavior I needed.
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];
I'm trying to get a UIScrollView to work correctly inside of a UICollectionViewCell.
The custom cell is being loaded in via a xib file and is a subclass of UICollectionViewCell. I had problems getting other controls working, such as a button and a gesture recognizer since the UICollecitonView doesn't seem to be passing any touches to the cells, but I got around those with gesture recognizers on the UICollectionView itself. The one remaining issue I have is the UIScrollViews...
The UICollectionView scrolls horizontally, and the UIScrollView in the cells scroll vertically. I've tried using a UIPanGestureRecognizer to scroll them, but that seems to disable the UICollectionView's ability to scroll.
Anybody have any thoughts?
EDIT: Got it!
So I had converted to a collection view from a previous third party library we were using before iOS6. Turns out the problem was with the xib files we were using for the cells. With the library before, the cells were just subclasses of UIViews. I changed the classes to subclass UICollectionViewCell, and updated the Custom Class. Turns out this was not enough. In order for touches to get passed to the cells I needed to actually had to drag in a new UICollectionViewCell from the Object library, copy over all the subviews and reconnect the IBOutlets. After this, it worked!
I fixed this in my code by making sure resizing of the scroll view happens on main thread.
My collection view is using nsfetchedresultscontroller that is using block calls to refresh selected cells. On the first time a cell was selected the scrollview would not scroll. However if you clicked on another cell and clicked back it would work fine. The initial load of the cell seemed like size calc might not be where it needed to be on main thread to affect behavior.
-(UICollectionViewCell *) collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:#"CustomCell" forIndexPath:indexPath];
dispatch_async(dispatch_get_main_queue(), ^{
// resizeScrollViewMethod should be where scrollview content size > scroll view frame.
[cell resizeScrollViewMethod];
});
return cell;
}
- (void) resizeScrollViewMethod {
//Do your scrollview size calculation here
}
No problem with UISCrollView in UICollectionViewCell. Use StoryBoard and you'll scroll OK.
UIScrollView overlay UICollectionViewCell, so that didSelect work only when tap outside ScrollView and inside Cell (scrollView.frame < cell.frame).
If you want to implement tap or other gesture, just add it to UIScrollView in awakeFromNib
Refer code:
https://github.com/lequysang/github_zip/blob/master/CollectionViewWithCellScrollViewStoryBoard.zip