如何知道 UITableView 何时在 iPhone 中滚动到底部？

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.

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.

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")
}
}

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
}
}

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");
}
}

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:

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");
}
}

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

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.

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");
}
}

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];
}
}

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!")
}
}

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
}

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
}
}

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")
}
}

@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
}