How to scroll UICollectionView to the bottom programatically? - ios

I have a UICollectionView. I want to scroll to the bottom when the view appears. How to do this?
Can someone help me out on this?.
Thanks in advance.

You can use the below code to scroll a UICollectionView programmatically to the bottom
NSInteger section = [self numberOfSectionsInCollectionView:collectionView] - 1;
NSInteger item = [self collectionView:collectionView numberOfItemsInSection:section] - 1;
NSIndexPath *lastIndexPath = [NSIndexPath indexPathForItem:item inSection:section];
[collectionView scrollToItemAtIndexPath:lastIndexPath atScrollPosition:UICollectionViewScrollPositionBottom animated:YES];

NSIndexPath *lastItem = /*Indexpath of last item*/;
[self.collectionView scrollToItemAtIndexPath:lastItem atScrollPosition:UICollectionViewScrollPositionBottom animated:YES];

you this code to scoll down.
NSArray *visibleItems = [self.collectionView indexPathsForVisibleItems];
NSIndexPath *currentItem = [visibleItems objectAtIndex:0];
NSIndexPath *nextItem = [NSIndexPath indexPathForItem:currentItem.item + 1 inSection:currentItem.section];
[self.collectionView scrollToItemAtIndexPath:nextItem atScrollPosition:UICollectionViewScrollPositionTop animated:YES];

set the contentoffset.y of your collection view object.

Related

Scroll collection view after finished editing textfield

I want to scroll my collection view to the next cell after the user has finished editing a textfield.
My textfield delegate methods are getting called, and I can scroll the collection view at the press of a button, the two combined together don't work though.
-(BOOL)textFieldShouldReturn:(UITextField*)textField {
[textField resignFirstResponder];
NSArray *visibleItems = [self.collectionView indexPathsForVisibleItems];
NSIndexPath *currentItem = [visibleItems objectAtIndex:0];
NSIndexPath *nextItem = [NSIndexPath indexPathForItem:currentItem.item + 1 inSection:currentItem.section];
[self.collectionView scrollToItemAtIndexPath:nextItem atScrollPosition:UICollectionViewScrollPositionRight animated:YES];
return YES;
}
Any ideas?
if you want to scroll when you you finish editing a textfield than use textFieldDidEndEditing method.
Try this code...
- (void)textFieldDidEndEditing:(UITextField *)textField
{
NSArray *visibleItems = [self.collectionView indexPathsForVisibleItems];
NSIndexPath *currentItem = [visibleItems objectAtIndex:0];
NSIndexPath *nextItem = [NSIndexPath indexPathForItem:currentItem.item + 1 inSection:currentItem.section];
[self.collectionView scrollToItemAtIndexPath:nextItem atScrollPosition:UICollectionViewScrollPositionRight animated:YES];
}

Move index path by one in TableView (iOS)

I have a chat application, in which i want to increase the index path by one when new chat data come. But it is not happening through my code I am sharing code with screen shot please help.
NSUInteger messageCount = [self numberOfMessages];
if (self.conversation && messageCount > 0) {
NSLog(#"%ld",(long)indexPathValue.row);
NSIndexPath* ip = [NSIndexPath indexPathForRow:indexPathValue.row + 1 inSection:0];
NSLog(#"%ld",(long)ip.row);
[layerChatTableView scrollToRowAtIndexPath:ip atScrollPosition:UITableViewScrollPositionTop animated:YES];
}
Below code allows you to go last indexpath with scroll position of bottom.
[tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:messageCoutnt-1 inSection:0] atScrollPosition:UITableViewScrollPositionButtom animated:NO];
Try and let me know
I am assuming that you have handled the datasource updating part and that you are updating the table view on main thread.
You can try to add new row at bottom like this:
NSInteger section = 0;
NSInteger newCount = [self tableView:self.tableView numberOfRowsInSection:section];
NSMutableArray *paths = #[].mutableCopy;
[paths addObject:[NSIndexPath indexPathForRow:newCount inSection:section]];
[self.tableView beginUpdates];
[self.tableView insertRowsAtIndexPaths:paths withRowAnimation:UITableViewRowAnimationNone];
[self.tableView endUpdates];
You can also add more than 1 row with some modifications.
Hope this helps.

iOS: Collection view, selectItemAtIndexPath programmatically doesn't work

I don't know why this doesn't work. indexOfIcon is correct, section is correct (checked with NSLog) If I select one everything is correct. But this line doesn't do a thing...why? If selected it should have a blue border. This works great while doing it "manually" but not with code..
- (void)viewWillAppear:(BOOL)animated
{
NSUInteger indexOfIcon;
if(self.mainCategory.icon){
indexOfIcon = [self.icons indexOfObject: self.mainCategory.icon];
} else {
indexOfIcon = 0;
}
[self.collectionView selectItemAtIndexPath:[NSIndexPath indexPathForRow:indexOfIcon inSection:0] animated:YES scrollPosition:UICollectionViewScrollPositionBottom];
}
add
UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
cell.selected = YES;
and the cell will be selected.
The command [self.collectionView selectItemAtIndexPath:[NSIndexPath indexPathForRow:indexOfIcon inSection:0] animated:YES scrollPosition:UICollectionViewScrollPositionBottom]; tells the collectionView, that the cell is in selected state, but don't set the state of the cell.
After years selection seems to work fine (even in viewDidLoad:)
NSIndexPath *indexPath = [NSIndexPath indexPathForItem:0 inSection:0];
[_collection selectItemAtIndexPath:indexPath animated:NO scrollPosition:UICollectionViewScrollPositionLeft];
successfully triggers cell's -setSelected:

TableView cell not scrolled on top after 3rd section in iOS7

I want scroll table view cell on top after clicked on cell, It is working up to 1 and 2 section but after that cell hidden behind "Keyboard".
- (void)scrollCellOnTop:(NSIndexPath *)indexPath
{
if(IS_IOS7)
{
self.supplierDetailTable .contentInset = UIEdgeInsetsMake(SCREEN_X,SCREEN_Y, self.supplierDetailTable.bounds.size.height-50, 0);
}
else
{
self.supplierDetailTable .contentInset = UIEdgeInsetsMake(SCREEN_X, SCREEN_Y, self.supplierDetailTable.bounds.size.height*tableInsetFraction, 0);
}
[ self.supplierDetailTable scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionTop animated:YES];
}
Please give me a solution if you have.
In order to scroll to a row in table view, you should do like below instead:
NSIndexPath *showOnTop = [NSIndexPath indexPathForRow:row_index inSection:section_index];
[table scrollToRowAtIndexPath:showOnTop atScrollPosition:UITableViewScrollPositionTop animated:YES];
Try replace line:
[ self.supplierDetailTable scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionTop animated:YES];
with:
NSIndexPath *iP = [NSIndexPath indexPathForRow:0 inSection:indexPath.section];
[self.supplierDetailTable scrollToRowAtIndexPath:iP atScrollPosition:UITableViewScrollPositionTop animated:YES];

how can i get the section number of a selected custom TableViewCell?

how can i find out in which section i clicked? i need the number to send the item to another view:
- (IBAction)mapButton:(id)sender {
UIButton * myButton = sender;
int row=myButton.tag;
NSIndexPath * indexPath = [NSIndexPath indexPathForRow:row inSection:0];
MapViewController *detail = [self.storyboard instantiateViewControllerWithIdentifier:#"mapView"];
self.selectedStandort = [self.fetchedResultsController objectAtIndexPath:indexPath];
detail.currentStandort = self.selectedStandort;
[self.navigationController pushViewController:detail animated:YES];
}
Is the mapButton a subview of the UITableViewCell?
Then I would do the following:
NSView *contentView = [sender superview];
NSTableViewCell *cell = (UITableViewCell *)[contentView superview];
NSIndexPath *cellIndexPath = [myTableView indexPathForCell:cell];
NSInteger section = cellIndexPath.section;
You can also use the row from the cellIndexPath, so you don't have to keep your tag value up to date (e.g. on reuse, reorder and delete) which makes your implementation less error-prone.

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