I'm trying to programmatically select cells in a UICollection view. I'm new to Obj-C and I'm not quite sure how to use the selectItemAtIndexPath property. I can grab an array of the images the user has previously selected. It is just an array of numbers corresponding to named images. But I'm not sure how to use that information with selectItemAtIndexPath.
I've looked for examples of someone using
- (void)selectItemAtIndexPath:(NSIndexPath *)indexPath animated:(BOOL)animated scrollPosition:(UICollectionViewScrollPosition)scrollPosition
But I'm not sure how to use it with my UICollectionView so I can have the right cells selected when the view loads and thus be highlighted. I have multiple selection on.
You should call selectItemAtIndexPath: for each cell you want to highlight, like so:
[self.collectionView selectItemAtIndexPath:path animated:NO scrollPosition:UICollectionViewScrollPositionNone]
Note that for one item (and one only!) you probably want to set the animated property to YES and provide a scroll position (one item only because otherwise you're going to be making a lot of needless animation calls).
You'll first need to get the index paths of the cells you want to select. The index path consists of two numbers: the section the cell is in and the row number (or order, if your collection view doesn't have rows) of the cell inside that section.
If you store the index paths of the cells the user has selected in an array then you can just iterate through. Otherwise you'll need to find the index path out, using a UICollectionView method such as indexPathForCell.
Related
i have the indexPath number... i need to remove the cell accessory from that cell based on the number in the variable i have?
NSInteger *removeAccessoryFrom = 3;
[studentTableView cellForRowAtIndexPath:removeAccessoryFrom].accessoryType = UITableViewCellAccessoryNone;
It doesn't work like that. You need to reload the table data (either for the whole table or for just this row) and, inside cellForRowAtIndexPath, set the accessoryType to UITableViewCellAccessoryNone conditionally. In other words, you keep a list, or have some other way of knowing, at every moment, and for the entire table, exactly what cells get exactly what accessory. That way, any time cellForRowAtIndexPath is called, you can configure this cell for this index path correctly.
I have a UITableView with gets populated from a backing array every time cellForRowAtIndexPath is called. The user can either go Back (via the nav bar) or they must submit the tableview's dataset to a server. Our GUI team wants the interface designed with a 'Done' button as the last cell in the table row in order to submit the dataset. Right now, numberOfRowsInSection is returning [myArray count] and I could conceivably alter the backing array with a "ghost" record for the done button, or simply return [myArray count] + 1 and catch the mis-matched array count in cellForRowAtIndexPath. Both ways, however, seem like trouble down the road. What's the best way to implement this?
Either put the button in the footer for the tableview, or mess with the row count. I've used both methods, just depends how much that last cell needs to look like the rest of the rows (or not look like them, in the case of using the footer)
My table view covers part of the view. If I have 20 objects, I am displaying all of them in a tableview. But I want to know that how many cell are loaded that are visible to the user.
(i.e. first 5 cells data is visible for me: when I scroll down, the remaining cells will load. Here I want to know without scrolling how many cell are loaded.)
Is this possible?
You can use [tableView visibleCells] count], which returns numbers of the table cells that are visible, if I understand correctly what you want.
The below code will give you the array of indexpath of cells currently visible
NSArray *visiblePaths = [self.tableView indexPathsForVisibleRows];
after getting the index path you can easily access the cell at a particular indexpath
Its usually : (tableView's height / cell row height ) + 1
Can you take the size of the visible part of the table, and then the size of one cell, and divide them to know how many of them fit in the screen?
I am using a custom tableviewcell in one of my view's. I have decided to add a UISwitch to this cell to enable the user to delete multiple row's at once.
Normally when the user selects a row and taps my delete button I have a UIAlert pop up for confirmation and after that the alert clickedButtonAtIndex method handles the outcome. In that method I get the indexpath ( [self.myTableView indexPathForSelectedRow] ) and delete (or not) accordingly.
So basically as the title states instead of using the indexPath to fall into my delete statement, I need to check to see if self.myTableView.myCell.mySwitch.on is TRUE. Can anyone point me in the right direction for doing this? I will need to iterate through all rows in the tableview and for each row where the state is on it needs to be removed.
Thanks.
you should iterate through your cells using a nested loop ( or a single loop if you have only one section) and cellForRowAtIndexPath:.if you see a cell's switch.on = TRUE save it's indexPath in an array by calling indexPathForCell:. after you're done iterating through your cells, call deleteRowsAtIndexPaths:withRowAnimation: with the array previously created.
Is there a way to move the highlighted tableviewcell programatically. If I wanted to highlight cell number 3 and then highlight cell number 4 instead, based on something the user did in the detail view of my split view controller, can I do this?
Is there a way I can get the indexpath for the row two below one that I have?
Thanks!
You can do this via the UITableView selectRowAtIndexPath:animated:scrollPosition: method.
In terms of getting the "next" row from the indexPath, you can simply use the indexPath.row property (as supplied from your UITableViewDelegate's tableView:didDeselectRowAtIndexPath: method) as the basis for the selected row.