I am using a collection view.
Although the directionLockEnabled can be set to YES, diagonal scrolling is still enabled.
So I found a solution somewhere:
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {
self.offset = self.collectionView.contentOffset;
}
// control scroll to only horizontal & vertical
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat deltaX = ABS(self.offset.x - self.collectionView.contentOffset.x);
CGFloat deltaY = ABS(self.offset.y - self.collectionView.contentOffset.y);
if (deltaX != 0 && deltaY != 0) {
if (deltaX >= deltaY) {
self.collectionView.contentOffset = CGPointMake(self.collectionView.contentOffset.x, self.offset.y);
}
else {
self.collectionView.contentOffset = CGPointMake(self.offset.x, self.collectionView.contentOffset.y);
}
}
}
However the side effect is when I call with x, y > 0
[self.collectionView setContentOffset:CGPointMake(x, y) animated:animated];
It doesn't scroll at all, because of the code block above.
How to deal with this?
To disable manually diagonal scrolling in Swift:
func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
self.offset = scrollView.contentOffset
}
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let deltaX = abs(self.offset.x - self.collectionView.contentOffset.x)
let deltaY = abs(self.offset.y - self.collectionView.contentOffset.y)
if deltaX != 0 && deltaY != 0 {
if deltaX >= deltaY {
self.collectionView.contentOffset = CGPoint(x: self.collectionView.contentOffset.x, y: self.offset.y)
} else {
self.collectionView.contentOffset = CGPoint(x: self.offset.x, y: self.collectionView.contentOffset.y)
}
}
}
OK I figure it out...
scrollView.dragging can differentiate manual scrolling or auto scrolling...
You can do
collectionView.isScrollEnabled = false
It will disable a user from scrolling, but you will be able to scroll programmatically using
collectionView.scrollToItem(at:at:animated:)
Related
I have a ScrollView on a view, where the page control is sticky from the bottom.
The page control is animated in and shown when the page is scrolled to 48px from the bottom of the page and stays opacity 100% (shown) to the end of the page.
But I am unable to detect this behaviour. scrollView content Size is mentioned below.
ScrollView content Size:
width : 414.0
height : 852.0
I am using the below code.
//MARK: - ScrollView Delegate
extension RemoveViewController: UIScrollViewDelegate {
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let distanceFromBottom = scrollView.contentSize.height - scrollView.contentOffset.y
print(distanceFromBottom)
if distanceFromBottom >= 796 {
print(" you reached at desired bottom")
self.showPageControl(toShow: true)
} else {
self.showPageControl(toShow: false)
}
}
}
func showPageControl(toShow: Bool) {
if toShow {
if self.pageControl.alpha != 1 {
UIView.animate(withDuration: 0.300, animations: {
self.pageControl.alpha = 1
})
}
} else {
if self.pageControl.alpha != 0 {
UIView.animate(withDuration: 0.300, animations: {
self.pageControl.alpha = 0
})
}
}
}
Kindly let me know what I am doing incorrectly here.
You need to calculate the bottomOffset first, then calculate the difference between it and the contentOffset. If it's <= 56, then you reached a specific position.
let bottomOffset = scrollView.contentSize.height - scrollView.frame.size.height
let position = bottomOffset - scrollView.contentOffset.y
if position <= 56 {
print(" you reached at desired bottom")
self.showPageControl(toShow: true)
} else {
self.showPageControl(toShow: false)
}
I have a images inside uicollectionview cell which scroll horizontally, I want to achieve a feature like the facebook and photo app apple, you click on image and it covers the whole screen. You can pinch and pan the image, I want to add certain limitations same like the facebook and photo app, like when you pinch the picture you can pan maximum to its width.
I want the image to recenter again if user try to move image out of the boundaries. I am adding some screenshots to give idea about it.
Right now I am using the simple code.
guard gestureRecognizer.view != nil else {return}
print(self.imgView.frame)
if self.imgView.frame.size.width < (self.imgOrignal.width+100) {
return
}
let piece = gestureRecognizer.view!
// Get the changes in the X and Y directions relative to
// the superview's coordinate space.
let translation = gestureRecognizer.translation(in: piece.superview)
if gestureRecognizer.state == .began {
self.initialCenter = piece.center
}
// Update the position for the .began, .changed, and .ended states
if gestureRecognizer.state != .cancelled {
// Add the X and Y translation to the view's original position.
let newCenter = CGPoint(x: initialCenter.x + translation.x, y: initialCenter.y + translation.y)
piece.center = newCenter
}
else {
// On cancellation, return the piece to its original location.
piece.center = initialCenter
}
}
I have resolved this issue by using UIScrollView zoom in and out, instead of using pinch and pan gesture, If any one wants to implement that functionality i am adding my code below.
func setZoomScale() {
let widthScale = self.bgView.frame.size.width / self.imgView.bounds.width
let heightScale = self.bgView.frame.size.height / self.imgView.bounds.height
let minScale = min(widthScale, heightScale)
self.imgScrollView.minimumZoomScale = minScale
self.imgScrollView.zoomScale = minScale
}
extension YOUR CLASS: UIScrollViewDelegate {
func viewForZooming(in scrollView: UIScrollView) -> UIView? {
return self.imgView
}
func scrollViewDidZoom(_ scrollView: UIScrollView) {
let imageViewSize = self.imgView.frame.size
let scrollViewSize = scrollView.bounds.size
let verticalInset = imageViewSize.height < scrollViewSize.height ? (scrollViewSize.height - imageViewSize.height) / 2 : 0
let horizontalInset = imageViewSize.width < scrollViewSize.width ? (scrollViewSize.width - imageViewSize.width) / 2 : 0
scrollView.contentInset = UIEdgeInsets(top: verticalInset, left: horizontalInset, bottom: verticalInset, right: horizontalInset)
}
}
I have a Scrollview in my app that shows a few slides,
the default behaviour of the slides are when you reach the last one (ie slide 5 for example) is that it doesn't scroll more to the right,
or when you go to the first one it doesn't scroll more to the left.
how do I make it infinity loop , meaning when I see the last slide, and I scroll more right, it will just scroll to the first one?
(or from the first one left it will scroll to the last one)
here is my scrollViewDidScroll:
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let pageIndex = round(scrollView.contentOffset.x/view.frame.width)
pageControl.currentPage = Int(pageIndex)
let maximumHorizontalOffset: CGFloat = scrollView.contentSize.width - scrollView.frame.width
let currentHorizontalOffset: CGFloat = scrollView.contentOffset.x
// vertical
let maximumVerticalOffset: CGFloat = scrollView.contentSize.height - scrollView.frame.height
let currentVerticalOffset: CGFloat = scrollView.contentOffset.y
let percentageHorizontalOffset: CGFloat = currentHorizontalOffset / maximumHorizontalOffset
let percentageVerticalOffset: CGFloat = currentVerticalOffset / maximumVerticalOffset
/*
* below code changes the background color of view on paging the scrollview
*/
// self.scrollView(scrollView, didScrollToPercentageOffset: percentageHorizontalOffset)
/*
* below code scales the imageview on paging the scrollview
*/
let percentOffset: CGPoint = CGPoint(x: percentageHorizontalOffset, y: percentageVerticalOffset)
print ("present offset: ", percentOffset.x)
if(percentOffset.x > 0 && percentOffset.x <= 0.25) {
slides[0].mainPic.transform = CGAffineTransform(scaleX: (0.25-percentOffset.x)/0.25, y: (0.25-percentOffset.x)/0.25)
slides[1].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x/0.25, y: percentOffset.x/0.25)
} else if(percentOffset.x > 0.25 && percentOffset.x <= 0.50) {
slides[1].mainPic.transform = CGAffineTransform(scaleX: (0.50-percentOffset.x)/0.25, y: (0.50-percentOffset.x)/0.25)
slides[2].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x/0.50, y: percentOffset.x/0.50)
} else if(percentOffset.x > 0.50 && percentOffset.x <= 0.75) {
slides[2].mainPic.transform = CGAffineTransform(scaleX: (0.75-percentOffset.x)/0.25, y: (0.75-percentOffset.x)/0.25)
slides[3].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x/0.75, y: percentOffset.x/0.75)
} else if(percentOffset.x > 0.75 && percentOffset.x <= 1) {
slides[3].mainPic.transform = CGAffineTransform(scaleX: (1-percentOffset.x)/0.25, y: (1-percentOffset.x)/0.25)
slides[4].mainPic.transform = CGAffineTransform(scaleX: percentOffset.x, y: percentOffset.x)
}
}
Not sure about your current implementation but your solution will be something like, I'm assuming your slides array contains UIView for each slide. Change the code according to your current implementation.
(void)scrollViewDidScroll:(UIScrollView *)scrollView {
if(if(scrollView.contentOffset.x < 0)) {
CGPoint newOffset = CGPointMake(scrollView.bounds.size.width+scrollView.contentOffset.x, scrollView.contentOffset.y);
[scrollView setContentOffset:newOffset];
[self rotateViewsRight];
}
else if(scrollView.contentOffset.x > scrollView.bounds.size.width*2) {
CGPoint newOffset = CGPointMake(scrollView.contentOffset.x-scrollView.bounds.size.width, scrollView.contentOffset.y);
[scrollView setContentOffset:newOffset];
[self rotateViewsLeft];
}
}
-(void)rotateViewsRight {
UIView *endView = [slides lastObject];
[slides removeLastObject];
[slides insertObject:endView atIndex:0];
[self setContentViewFrames];
}
-(void)rotateViewsLeft {
UIView *endView = slides[0];
[slides removeObjectAtIndex:0];
[slides addObject:endView];
[self setContentViewFrames];
}
-(void) setContentViewFrames {
for(int i = 0; i < 5; i++) {
UIView * view = slides[i];
[view setFrame:CGRectMake(self.view.bounds.size.width*i, 0, self.view.bounds.size.width, self.view.bounds.size.height)];
}
}
I have a UIView with a UITableView below it:
What I would like to do is to have the view above the UITableView move up (out of the way) when the user starts scrolling in the table in order to have more space for the UITableView (and come down when you scroll down again).
I know that this is normally done with a table header view, but my problem is that my table view is inside a tab (actually it is a side-scrolling page view implemented using TTSliddingPageviewcontroller). So while I only have one top UIView there are three UITableViews.
Is it possible to accomplish this manually? My first thought is to put everything in a UIScrollView, but according to Apple's documentation one should never place a UITableView inside a UIScrollView as this leads to unpredictable behavior.
Solution for Swift (Works perfectly with bounce enabled for scroll view):
var oldContentOffset = CGPointZero
let topConstraintRange = (CGFloat(120)..<CGFloat(300))
func scrollViewDidScroll(scrollView: UIScrollView) {
let delta = scrollView.contentOffset.y - oldContentOffset.y
//we compress the top view
if delta > 0 && topConstraint.constant > topConstraintRange.start && scrollView.contentOffset.y > 0 {
topConstraint.constant -= delta
scrollView.contentOffset.y -= delta
}
//we expand the top view
if delta < 0 && topConstraint.constant < topConstraintRange.end && scrollView.contentOffset.y < 0{
topConstraint.constant -= delta
scrollView.contentOffset.y -= delta
}
oldContentOffset = scrollView.contentOffset
}
Since UITableView is a subclass of UIScrollView, your table view's delegate can receive UIScrollViewDelegate methods.
In your table view's delegate:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
static CGFloat previousOffset;
CGRect rect = self.view.frame;
rect.origin.y += previousOffset - scrollView.contentOffset.y;
previousOffset = scrollView.contentOffset.y;
self.view.frame = rect;
}
More simple and fast approach
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGRect rect = self.view.frame;
rect.origin.y = -scrollView.contentOffset.y;
self.view.frame = rect;
}
Swift 3 & 4:
var oldContentOffset = CGPoint.zero
let topConstraintRange = (CGFloat(0)..<CGFloat(140))
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let delta = scrollView.contentOffset.y - oldContentOffset.y
//we compress the top view
if delta > 0 && yourConstraint.constant > topConstraintRange.lowerBound && scrollView.contentOffset.y > 0 {
yourConstraint.constant -= delta
scrollView.contentOffset.y -= delta
}
//we expand the top view
if delta < 0 && yourConstraint.constant < topConstraintRange.upperBound && scrollView.contentOffset.y < 0{
yourConstraint.constant -= delta
scrollView.contentOffset.y -= delta
}
oldContentOffset = scrollView.contentOffset
}
I added some constraints to the last solution to prevent some strange behaviours in case of fast scrolling
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let delta = scrollView.contentOffset.y - oldContentOffset.y
//we compress the top view
if delta > 0 && topConstraint.constant > topConstraintRange.lowerBound && scrollView.contentOffset.y > 0 {
searchHeaderTopConstraint.constant = max(topConstraintRange.lowerBound, topConstraint.constant - delta)
scrollView.contentOffset.y -= delta
}
//we expand the top view
if delta < 0 && topConstraint.constant < topConstraintRange.upperBound && scrollView.contentOffset.y < 0 {
topConstraint.constant = min(searchHeaderTopConstraint.constant - delta, topConstraintRange.upperBound)
scrollView.contentOffset.y -= delta
}
oldContentOffset = scrollView.contentOffset
}
Someone asked for the code for my solution so I am posting it here as an answer. The credit for the idea should still go to NobodyNada.
In my UITableViewController I implement this delegate method:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
[[NSNotificationCenter defaultCenter] postNotificationName:#"TableViewScrolled" object:nil userInfo:scrollUserInfo];
}
scrollUserInfo is a NSDictionary where I put my UITableView to pass it with the notification (I do this in viewDidLoad so I only have to do it once):
scrollUserInfo = [NSDictionary dictionaryWithObject:self.tableView forKey:#"scrollView"];
Now, in the view controller that has the view I want to move off screen while scrolling I do this in viewDidLoad:
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(handleScroll:) name:#"TableViewScrolled" object:nil];
And finally I have the method:
- (void)handleScroll:(NSNotification *)notification {
UIScrollView *scrollView = [notification.userInfo valueForKey:#"scrollView"];
CGFloat currentOffset = scrollView.contentOffset.y;
CGFloat height = scrollView.frame.size.height;
CGFloat distanceFromBottom = scrollView.contentSize.height - currentOffset;
if (previousOffset < currentOffset && distanceFromBottom > height) {
if (currentOffset > viewHeight)
currentOffset = viewHeight;
self.topVerticalConstraint.constant += previousOffset - currentOffset;
previousOffset = currentOffset;
}
else {
if (previousOffset > currentOffset) {
if (currentOffset < 0)
currentOffset = 0;
self.topVerticalConstraint.constant += previousOffset - currentOffset;
previousOffset = currentOffset;
}
}
}
previousOffset is an instance variable CGFloat previousOffset;.
topVerticalConstraint is a NSLayoutConstraint that is set as a IBOutlet. It goes from the top of the view to the top of its superview and the initial value is 0.
It's not perfect. For instance, if the user scrolls very aggressively up the movement of the view can get a bit jerky. The issue is worse for large views; if the view is small enough there is no problem.
To create like this animation,
lazy var redView: UIView = {
let view = UIView(frame: CGRect(x: 0, y: 0, width:
self.view.frame.width, height: 100))
view.backgroundColor = .red
return view
}()
var pageMenu: CAPSPageMenu?
override func viewDidLoad() {
super.viewDidLoad()
self.view.addSubview(redView)
let rect = CGRect(x: 0, y: self.redView.frame.maxY, width: self.view.bounds.size.width, height:(self.view.bounds.size.height - (self.redView.frame.maxY)))
pageMenu?.view.frame = rect
self.view.addSubview(pageMenu!.view)
}
override func scrollViewDidScroll(_ scrollView: UIScrollView) {
let offset = scrollView.contentOffset.y
if(offset > 100){
self.redView.frame = CGRect(x: 0, y: 0, width: self.view.bounds.size.width, height: 0)
}else{
self.redView.frame = CGRect(x: 0, y: 0, width: self.view.bounds.size.width, height: 100 - offset)
}
let rect = CGRect(x: 0, y: self.redView.frame.maxY, width: self.view.bounds.size.width, height:(self.view.bounds.size.height - (self.redView.frame.maxY)))
pageMenu?.view.frame = rect
}
you must change pageMenu.view with your collectionView/tableView
I know this post in very old. I tried above solutions but neither worked for me for tried my own, hopefully it can help you. This scenario is pretty common, as apple suggested not to use TableViewController inside any ScrollView because the compiler will confused as in whom to respond becuase it will be getting two delegate call back - one from ScrollViewDelegate and another from UITableViewDelegate.
Instead we can use ScrollViewDelegate and disable the UITableViewScrolling.
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat currentOffSetY = scrollView.contentOffset.y;
CGFloat diffOffset = self.lastContentOffset - currentOffSetY;
self.scrollView.contentSize = CGSizeMake(self.scrollView.contentSize.width, 400 + [self.tableView contentSize].height);
if (self.lastContentOffset < scrollView.contentOffset.y) {
tableView.frame = CGRectMake(tableView.frame.origin.x, tableView.frame.origin.y , tableView.frame.size.width, tableView.size.height - diffOffset);
}
if (self.lastContentOffset > scrollView.contentOffset.y) {
tableView.frame = CGRectMake(tableView.frame.origin.x, tableViewframe.origin.y, tableViewframe.size.width, tableView.frame.size.height + diffOffset);
}
self.lastContentOffset = currentOffSetY;
}
Here lastContentOffset is CGFloat defined as property
The View Heirarchy is as follows:
ViewController --> View contains ScrollView (whose delegate method is defined above) --> Contain TableView.
By the above code we are manually increasing and decreasing the height of the table view along with the content size of ScrollView.
Remember to disable the Scrolling of TableView.
You can make it like this:
Add these as your class variables:
private let NUMBER_OF_ROWS: Int = 256
private let ROW_HEIGHT: CGFloat = 75.0
private let MINIMUM_CONSTANT_VALUE: CGFloat = -150.0 /// This is the hidable view's height
#IBOutlet weak var hidableViewTopConstraint: NSLayoutConstraint! /// This is an outlet from your storyboard
private var lastContentOffset: CGFloat = 0.0
This goes on your viewDidLoad():
tableView.delegate = self
And then you add this as an extension for your view controller:
extension ViewController: UIScrollViewDelegate {
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let delta = tableView.contentOffset.y - lastContentOffset
let canScrollUp: Bool =
delta < 0 &&
hidableViewTopConstraint.constant < 0 &&
scrollView.contentOffset.y < 0
let canScrollDown: Bool =
delta > 0 &&
hidableViewTopConstraint.constant > MINIMUM_CONSTANT_VALUE &&
tableView.contentOffset.y > 0
if canScrollUp || canScrollDown{
hidableViewTopConstraint.constant -= delta
tableView.contentOffset.y -= delta
}
lastContentOffset = tableView.contentOffset.y
}
}
But note that the scroll mechanism will only work when the TableView is scrolled. The top view wont collapse or expand if you scroll it.
I made an example project you can check, it is called iOSFixedHeaderList
I would like to know when a UITableView did scroll to bottom in order to load and show more content, something like a delegate or something else to let the controller know when the table did scroll to bottom.
How can I do this?
in the tableview delegate do something like this
ObjC:
- (void)scrollViewDidScroll:(UIScrollView *)aScrollView {
CGPoint offset = aScrollView.contentOffset;
CGRect bounds = aScrollView.bounds;
CGSize size = aScrollView.contentSize;
UIEdgeInsets inset = aScrollView.contentInset;
float y = offset.y + bounds.size.height - inset.bottom;
float h = size.height;
// NSLog(#"offset: %f", offset.y);
// NSLog(#"content.height: %f", size.height);
// NSLog(#"bounds.height: %f", bounds.size.height);
// NSLog(#"inset.top: %f", inset.top);
// NSLog(#"inset.bottom: %f", inset.bottom);
// NSLog(#"pos: %f of %f", y, h);
float reload_distance = 10;
if(y > h + reload_distance) {
NSLog(#"load more rows");
}
}
Swift:
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let offset = scrollView.contentOffset
let bounds = scrollView.bounds
let size = scrollView.contentSize
let inset = scrollView.contentInset
let y = offset.y + bounds.size.height - inset.bottom
let h = size.height
let reload_distance:CGFloat = 10.0
if y > (h + reload_distance) {
print("load more rows")
}
}
Modified neoneyes answer a bit.
This answer targets those of you who only wants the event to be triggered once per release of the finger.
Suitable when loading more content from some content provider (web service, core data etc).
Note that this approach does not respect the response time from your web service.
- (void)scrollViewDidEndDragging:(UIScrollView *)aScrollView
willDecelerate:(BOOL)decelerate
{
CGPoint offset = aScrollView.contentOffset;
CGRect bounds = aScrollView.bounds;
CGSize size = aScrollView.contentSize;
UIEdgeInsets inset = aScrollView.contentInset;
float y = offset.y + bounds.size.height - inset.bottom;
float h = size.height;
float reload_distance = 50;
if(y > h + reload_distance) {
NSLog(#"load more rows");
}
}
add this method in the UITableViewDelegate:
-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGFloat height = scrollView.frame.size.height;
CGFloat contentYoffset = scrollView.contentOffset.y;
CGFloat distanceFromBottom = scrollView.contentSize.height - contentYoffset;
if(distanceFromBottom < height)
{
NSLog(#"end of the table");
}
}
None of the answers above helped me, so I came up with this:
- (void)scrollViewDidEndDecelerating:(UIScrollView *)aScrollView
{
NSArray *visibleRows = [self.tableView visibleCells];
UITableViewCell *lastVisibleCell = [visibleRows lastObject];
NSIndexPath *path = [self.tableView indexPathForCell:lastVisibleCell];
if(path.section == lastSection && path.row == lastRow)
{
// Do something here
}
}
The best way is to test a point at the bottom of the screen and use this method call when ever the user scrolls (scrollViewDidScroll):
- (NSIndexPath *)indexPathForRowAtPoint:(CGPoint)point
Test a point near the bottom of the screen, and then using the indexPath it returns check if that indexPath is the last row then if it is, add rows.
Use – tableView:willDisplayCell:forRowAtIndexPath: (UITableViewDelegate method)
Simply compare the indexPath with the items in your data array (or whatever data source you use for your table view) to figure out if the last element is being displayed.
Docs: http://developer.apple.com/library/ios/documentation/uikit/reference/UITableViewDelegate_Protocol/Reference/Reference.html#//apple_ref/occ/intfm/UITableViewDelegate/tableView:willDisplayCell:forRowAtIndexPath:
UITableView is a subclass of UIScrollView, and UITableViewDelegate conforms to UIScrollViewDelegate. So the delegate you attach to the table view will get events such as scrollViewDidScroll:, and you can call methods such as contentOffset on the table view to find the scroll position.
NSLog(#"%f / %f",tableView.contentOffset.y, tableView.contentSize.height - tableView.frame.size.height);
if (tableView.contentOffset.y == tableView.contentSize.height - tableView.frame.size.height)
[self doSomething];
Nice and simple
in Swift you can do something like this. Following condition will be true every time you reach end of the tableview
func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
if indexPath.row+1 == postArray.count {
println("came to last row")
}
}
Building on #Jay Mayu's answer, which I felt was one of the better solutions:
Objective-C
// UITableViewDelegate
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
// Need to call the service & update the array
if(indexPath.row + 1 == self.sourceArray.count) {
DLog(#"Displayed the last row!");
}
}
Swift 2.x
// UITableViewDelegate
func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
if (indexPath.row + 1) == sourceArray.count {
print("Displayed the last row!")
}
}
Here is the swift 3.0 version code.
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let offset = scrollView.contentOffset
let bounds = scrollView.bounds
let size = scrollView.contentSize
let inset = scrollView.contentInset
let y: Float = Float(offset.y) + Float(bounds.size.height) + Float(inset.bottom)
let height: Float = Float(size.height)
let distance: Float = 10
if y > height + distance {
// load more data
}
}
I generally use this to load more data , when last cell starts display
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (indexPath.row == myDataArray.count-1) {
NSLog(#"load more");
}
}
Taking neoneye excellent answers but in swift, and renaming of the variables..
Basically we know we have reached the bottom of the table view if the yOffsetAtBottom is beyond the table content height.
func isTableViewScrolledToBottom() -> Bool {
let tableHeight = tableView.bounds.size.height
let contentHeight = tableView.contentSize.height
let insetHeight = tableView.contentInset.bottom
let yOffset = tableView.contentOffset.y
let yOffsetAtBottom = yOffset + tableHeight - insetHeight
return yOffsetAtBottom > contentHeight
}
My solution is to add cells before tableview will decelerate on estimated offset. It's predictable on by velocity.
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)offset {
NSLog(#"offset: %f", offset->y+scrollView.frame.size.height);
NSLog(#"Scroll view content size: %f", scrollView.contentSize.height);
if (offset->y+scrollView.frame.size.height > scrollView.contentSize.height - 300) {
NSLog(#"Load new rows when reaches 300px before end of content");
[[DataManager shared] fetchRecordsNextPage];
}
}
Update for Swift 3
Neoneye's answer worked best for me in Objective C, this is the equivalent of the answer in Swift 3:
func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
let offset: CGPoint = scrollView.contentOffset
let bounds: CGRect = scrollView.bounds
let size: CGSize = scrollView.contentSize
let inset: UIEdgeInsets = scrollView.contentInset
let y: CGFloat = offset.y + bounds.size.height - inset.bottom
let h: CGFloat = size.height
// print("offset: %f", offset.y)
// print("content.height: %f", size.height)
// print("bounds.height: %f", bounds.size.height)
// print("inset.top: %f", inset.top)
// print("inset.bottom: %f", inset.bottom)
// print("position: %f of %f", y, h)
let reloadDistance: CGFloat = 10
if (y > h + reloadDistance) {
print("load more rows")
}
}
I want perform some action on my any 1 full Tableviewcell.
So the code is link the :
-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
NSArray* cells = self.tableView.visibleCells;
NSIndexPath *indexPath = nil ;
for (int aIntCount = 0; aIntCount < [cells count]; aIntCount++)
{
UITableViewCell *cell = [cells objectAtIndex:aIntCount];
CGRect cellRect = [self.tableView convertRect:cell.frame toView:self.tableView.superview];
if (CGRectContainsRect(self.tableView.frame, cellRect))
{
indexPath = [self.tableView indexPathForCell:cell];
// remain logic
}
}
}
May this is help to some one.
#neoneye's answer worked for me. Here is the Swift 4 version of it
let offset = scrollView.contentOffset
let bounds = scrollView.bounds
let size = scrollView.contentSize
let insets = scrollView.contentInset
let y = offset.y + bounds.size.height - insets.bottom
let h = size.height
let reloadDistance = CGFloat(10)
if y > h + reloadDistance {
//load more rows
}