How to maintain state of selection of row in table view? - iphone

Question

i am a beginner in xcode. I am creating a questionnaire type list with multiple rows in scroll. But when I select a row and scroll it doesn't retains its state and when I come back, it also loses its selection. So anyone please kindly let me know how to achieve that,i have tried something like this,
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if(val==1)
{
checkedArr=[[NSMutableArray alloc] init];
for (int i = 0; i<17; i++)
{
[checkedArr addObject:#"1"];
}
NSLog(#"Checked arr size %i",[checkedArr count]);
return 17;
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *CellIdentifier = [NSString stringWithFormat:#"Cell%i",indexPath.row];
cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell==nil)
{
cell= [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
cell.textLabel.numberOfLines = 0;
cell.textLabel.font = [UIFont fontWithName:#"Helvetica" size:14.0];
}
cell.textLabel.font = [UIFont fontWithName:#"Helvetica-Bold" size:18.0];
UIView *selectionColor = [[UIView alloc] init];
selectionColor.backgroundColor = [UIColor colorWithRed:99/255.0f green:209/255.0f blue:248/255.0f alpha:1.0];
cell.selectedBackgroundView = selectionColor;
if([[checkedArr objectAtIndex:indexPath.row] isEqual:#"0"])
{
cell.accessoryView=[[UIImageView alloc] initWithImage:[UIImage imageNamed:#"tick.png"]];
NSLog(#"checkedArr 0000000");
}
else if ([[checkedArr objectAtIndex:indexPath.row] isEqual:#"1"])
{
cell.accessoryView=nil;
NSLog(#"checkedArr 111111");
}
cell.textLabel.frame=CGRectMake(75.0, 50.0, 150.0, 20.0);
cell.textLabel.text=[listArray objectAtIndex:indexPath.row];
NSLog(#"Checked arr size %i",[checkedArr count]);
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
cell=[questionTable cellForRowAtIndexPath:indexPath];
[checkedArr replaceObjectAtIndex:indexPath.row withObject:#"0"];
if([[checkedArr objectAtIndex:indexPath.row] isEqual:#"0"])
{
cell.accessoryView=[[UIImageView alloc] initWithImage:[UIImage imageNamed:#"tick.png"]];
NSLog(#"checkedArr 0000000");
}
else if ([[checkedArr objectAtIndex:indexPath.row] isEqual:#"1"])
{[questionTable deselectRowAtIndexPath:indexPath animated:YES];
cell.accessoryView=nil;
NSLog(#"checkedArr 111111");
}
NSLog(#"Val is %i",val);
NSLog(#"selected is %#",[listArray objectAtIndex:indexPath.row]);
// NSLog(#"Checked arr descripton %#",[checkedArr description]);
}
-(void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableView cellForRowAtIndexPath:indexPath].accessoryView = UITableViewCellAccessoryNone;
}

Answer 1

In my application i used same code for check mark as accessoryType,check this.
take it in .h file mutable array arSelectedRows;
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
[cell setSelectionStyle:UITableViewCellSelectionStyleGray];
//Do anything you want for cell here
if([arSelectedRows containsObject:indexPath]) {
cell.accessoryType = UITableViewCellAccessoryCheckmark;
}
else {
cell.accessoryType = UITableViewCellAccessoryNone;
}
return cell;
}
#pragma mark - Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
if(cell.accessoryType == UITableViewCellAccessoryNone) {
cell.accessoryType = UITableViewCellAccessoryCheckmark;
[arSelectedRows addObject:indexPath];
}
else {
cell.accessoryType = UITableViewCellAccessoryNone;
[arSelectedRows removeObject:indexPath];
}
NSLog(#"arSelectedRows are :%#",arSelectedRows);
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}
EDIT
//if you want only single check mark
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[arSelectedRows removeAllObjects];
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
if(cell.accessoryType == UITableViewCellAccessoryNone) {
cell.accessoryType = UITableViewCellAccessoryCheckmark;
[arSelectedRows addObject:indexPath];
}
else {
cell.accessoryType = UITableViewCellAccessoryNone;
[arSelectedRows removeObject:indexPath];
}
NSLog(#"arSelectedRows are:%#",arSelectedRows);
[self.tableview reloadData];//Reload your tableview here
}
it will help you.

Answer 2

First your cellForRowAtIndexPath method create new cell each time whenever you scroll up/down tableView, it is very bad for memory management.
Just remove [questionTable deselectRowAtIndexPath:indexPath animated:YES] in your cellForRowAtIndexPath method

Answer 3

I think you need to use this api below:-
- (void)selectRowAtIndexPath:(NSIndexPath *)indexPath animated:(BOOL)animated scrollPosition:(UITableViewScrollPosition)scrollPosition

Answer 4

If you are using dynamic cells, and updating your row with some kind of class variable like a NSArray, you might have set your variable to weak instead of strong.