UITableviewCell height not getting reset on scroll - ios

Question

I have a tableview which can be expanded on selecting the cell and collapses on selecting again. When you select, the cell should expand and display a label and when you select again it collapses and hides the label . The expanding and collapsing works fine, but if i scroll the tableview after expanding a cell it behaves weird. Once it goes out of the view and comes back , the cell will have the expanded cell's height but the label which is supposed to be shown in expanded cell is hidden.If i select the cell again it collapses and displays the label. I use ,
- (CGFloat)tableView:(UITableView *)t heightForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [self tableView:t cellForRowAtIndexPath:indexPath];
if([self cellIsSelected:indexPath])
return cell.frame.size.height+35;
return cell.frame.size.height;
}
- (BOOL)cellIsSelected:(NSIndexPath *)indexPath {
// Return whether the cell at the specified index path is selected or not
NSNumber *selectedIndex = [self.selectedIndexes objectForKey:indexPath];
return selectedIndex == nil ? FALSE : [selectedIndex boolValue];
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// Deselect cell
NSLog(#"Select cell:%#",indexPath);
[self.tableView deselectRowAtIndexPath:indexPath animated:TRUE];
if([self pickTaskForIndexPath:indexPath].productSpecialMessage){
BOOL isSelected = ![self cellIsSelected:indexPath];
NSNumber *selectedIndex = [NSNumber numberWithBool:isSelected];
[self.selectedIndexes setObject:selectedIndex forKey:indexPath];
PickTaskTableviewCell *cell= [self.tableView cellForRowAtIndexPath:indexPath];
cell.message.hidden=false;
cell.messageLabel.text=[self pickTaskForIndexPath:indexPath].productSpecialMessage;
cell.messageLabel.lineBreakMode=NSLineBreakByTruncatingTail;
cell.messageLabel.numberOfLines=3;
if(cell.messageLabel.hidden==true){
cell.messageLabel.hidden = false;
} else {
cell.messageLabel.hidden = true;
}
NSLog(#"message:%#",cell.messageLabel.text);
[cell layoutIfNeeded];
}
self.tableView.rowHeight=UITableViewAutomaticDimension;
[self.tableView beginUpdates];
[self.tableView endUpdates];
}
indexPath is added to the selectedIndexes on didSelectRowAtIndexPath
Please help me

Answer 1

Cells should be configured only within cellForRowAtIndexPath. When a state change occurs that makes a cell need to look different, just reload that cell.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
PickTaskTableviewCell *cell = (PickTaskTableviewCell *)[tableView dequeueReusableCellWithIdentifier:#"cell"];
// everything else you do to configure the cell goes here, then ...
// check the logic here, we want one condition that tells us whether to show the labels
if([[self cellIsSelected:indexPath] && self pickTaskForIndexPath:indexPath].productSpecialMessage){
// don't need these here
//NSNumber *selectedIndex = [NSNumber numberWithBool:isSelected];
// [self.selectedIndexes setObject:selectedIndex forKey:indexPath];
// PickTaskTableviewCell *cell= [self.tableView cellForRowAtIndexPath:indexPath];
cell.message.hidden=false;
cell.messageLabel.text=[self pickTaskForIndexPath:indexPath].productSpecialMessage;
cell.messageLabel.lineBreakMode=NSLineBreakByTruncatingTail;
cell.messageLabel.numberOfLines=3;
cell.messageLabel.hidden=NO;
} else {
cell.message.hidden=YES;
cell.messageLabel.hidden=YES;
}
NSLog(#"message:%#",cell.messageLabel.text);
// don't need this here
// [cell layoutIfNeeded];
return cell;
}
Selection (and presumably deselection) cause the need to update the cell, so...
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// don't deselect it here, just reload it
// more on this later...
[self.selectedIndexes setObject:selectedIndex forKey:indexPath];
[self.tableView reloadRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
}
// probably do the same in didDeselectRowAtIndexPath:
One last (optional) point. There's no need to maintain your own list of selected index paths, UITableView does that for you, so you could delete your selectedIndexes property and just use the table view methods, e.g....
- (BOOL)cellIsSelected:(NSIndexPath *)indexPath {
// Return whether the cell at the specified index path is selected or not
return [[self.tableView indexPathsForSelectedRows] containsObject:indexPath];
}