get cell from indexPath for expand the row when clicked? - ios

Question

I know there is a method called [tableView cellForRowAtIndexPath:indexPath]; which we can use to get cell at given indexPath.But i want to expand row when the row tapped.using this code-
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// Deselect cell
[tableView deselectRowAtIndexPath:indexPath animated:TRUE];
// Toggle 'selected' state
BOOL isSelected = ![self cellIsSelected:indexPath];
// Store cell 'selected' state keyed on indexPath
NSNumber *selectedIndex = [NSNumber numberWithBool:isSelected];
int sec = indexPath.section;
int row = indexPath.row;
NSString* indexpathStr = [NSString stringWithFormat:#"%d-%d", sec, row];
[selectedIndexes setObject:selectedIndex forKey:indexpathStr];
// This is where magic happens...
[tableView beginUpdates];
[tableView endUpdates];
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
CGFloat height = 0.0;
if([self cellIsSelected:indexPath]) {
//problem here
CalEventCell* cell = (CalEventCell*)[tableView cellForRowAtIndexPath:indexPath];
[self setDescriptionFrame:cell.descriptionLbl];
height = cell.descriptionLbl.frame.size.height+cell.eventLbl.frame.size.height +20;
}
else
height = 60;
return height;
}
when a row tapped i call beginUpdates and endUpdates methods on tableview and change row height in heightForAtIndexPath method.The problem is that as you can see i call cellForAtIndexPath from heightForAtIndexPath and in cellForRow there is beginUpdates method call which turn into a call to heightForRow and this loop never ends and program crash with EXC-BAD-EXCEP.
So any other method to get cell from indexPath or any other way to do so? Any help would be appreciated.

Answer 1

Take an array to store the selected indices and then reload that tableview.
If you tap that cell height will expand and again if you will tap it will decrease its height.
Check out the below code.
// Add a mutable array to your class
NSMutableArray *selectedCellArray;
// Initialise it in `viewDidLoad`
-(void)viewDidLoad
{
[super viewDidLoad];
selectedCellArray = [[NSMutableArray alloc] init];
}
// Add selected indices in selectedCellArray
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// Deselect cell
[tableView deselectRowAtIndexPath:indexPath animated:TRUE];
[tableView reloadData];
if (![selectedCellArray containsObject:indexPath])
[selectedCellArray addObject:indexPath];
else
[selectedCellArray removeObject:indexPath];
[tableView beginUpdates]; // Animate the height change
[tableView endUpdates];
}
// Write the UI Updation in HeightForRowAtIndexPath Method
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
CGFloat height = 0.0;
if (selectedCellArray.count>0) {
if ([selectedCellArray containsObject:indexPath]) {
CalEventCell* cell = (CalEventCell*)[tableView cellForRowAtIndexPath:indexPath];
[self setDescriptionFrame:cell.descriptionLbl];
height = cell.descriptionLbl.frame.size.height+cell.eventLbl.frame.size.height+20;
return height;
}else{
height = 60.f;
return height;
}
}
return height;
}
Hope This Helps

Answer 2

You should call below lines of code on your didSelectRowAtIndexPath method
[tableView beginUpdates];
[tableView reloadRowsAtIndexPaths:#[[NSIndexPath indexPathForRow:row inSection:sec]] withRowAnimation:UITableViewRowAnimationNone];
[tableView endUpdates];
When row will be reloaded cellForRowAtIndexPath:indexPath and heightForRowAtIndexPath methods will be called where u can expand cell's height

Answer 3

You can't use cellForRowAtIndexPath in heightForRowAtIndexPath if you are using reusable cells. You need to calculate the height in some other way. The simplest way that would likely work for you would be to keep a prototype cell in your class that you only use for sizing purposes.

Answer 4

Try this:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[your_tableView reloadData];
}