Tableview forgetting selectedSegment in UISegmentedControl? - ios

Question

If i select some segments and then scroll the tableView down, it forgets my selected segments?
What am I do'ing wrong? Or what am I missing? It looks like it resets the cell every time, but I've tried to remove the cell = nil; but with no luck. All the code I think might have impact on this is here:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"FancyCell"];
cell = nil;
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"FancyCell"];
cell.accessoryType = UITableViewCellAccessoryDetailDisclosureButton;
// add the segmentedControl when you create a new cell
UIImage *correctImageGreen = [[UIImage imageNamed:#"green.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
UIImage *correctImageGul = [[UIImage imageNamed:#"gul.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
UIImage *correctImageRed = [[UIImage imageNamed:#"red.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
NSArray *itemArray = [NSArray arrayWithObjects: correctImageGreen, correctImageGul, correctImageRed, nil];
UISegmentedControl *segmentedControl = [[UISegmentedControl alloc] initWithItems:itemArray];
segmentedControl.frame = CGRectMake(308, 8, 150, 28);
[cell.contentView addSubview:segmentedControl];
// add an action so we can change our model if the view changes
[segmentedControl addTarget:self action:#selector(didChangeSegmentedControl:) forControlEvents:UIControlEventValueChanged];
// use a tag so we can retrieve the segmentedControl later
segmentedControl.tag = 42;
}
// either if the cell could be dequeued or you created a new cell,
// segmentedControl will contain a valid instance
UISegmentedControl *segmentedControl = (UISegmentedControl *)[cell.contentView viewWithTag:42];
UIImage *comment = [UIImage imageNamed:#"Checkmark-hvid"];
UIImage *imageRef = [UIImage imageNamed:#"Checkmark-hvid"];
UIImageView *commentView = [[UIImageView alloc] initWithImage: comment];
UIImageView *imageRefView = [[UIImageView alloc] initWithImage: imageRef];
commentView.frame = CGRectMake(625, 5, 30, 30);
imageRefView.frame = CGRectMake(515, 5, 30, 30);
commentView.tag = 98;
imageRefView.tag = 99;
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
boolean_t didGetStates = [defaults boolForKey:#"didGetStates"];
if (didGetStates) {
NSDictionary *dic = [tableData objectAtIndex:indexPath.row];
int selectedState = [[dic valueForKey:#"State"] intValue];
[cell.contentView addSubview:segmentedControl];
if (selectedState == -1) {
segmentedControl.selectedSegmentIndex = -1;
}
else {
segmentedControl.selectedSegmentIndex = selectedState;
}
int comment = [[dic valueForKey:#"Comment"] intValue];
int imageRef = [[dic valueForKey:#"Foto"] intValue];
if (comment == 0) {
[cell.contentView addSubview:commentView];
}
else {
[[cell.contentView viewWithTag:98]removeFromSuperview];
}
if (imageRef == 0) {
[cell.contentView addSubview:imageRefView];
}
else {
[[cell.contentView viewWithTag:99]removeFromSuperview];
}
}
MBFancyObject *object = _objects[indexPath.row];
cell.textLabel.text = object.title;
cell.selectionStyle = UITableViewCellSelectionStyleNone;
object.selectedIndex = segmentedControl.selectedSegmentIndex;
object.currentIndexRow = indexPath.row;
cell.backgroundColor = [UIColor clearColor];
cell.textLabel.textColor = [UIColor whiteColor];
return cell;
}
The action that is called, when a segment is chosen..
- (IBAction)didChangeSegmentedControl:(UISegmentedControl *)sender {
// transform the origin of the cell to the frame of the tableView
CGPoint senderOriginInTableView = [self.tableView convertPoint:CGPointZero fromView:sender];
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:senderOriginInTableView];
NSAssert(indexPath, #"must have a valid indexPath");
MBFancyObject *object = _objects[indexPath.row];
object.selectedIndex = sender.selectedSegmentIndex;
}
If you got any idea please write an answer or if you need more information tell me!! :)
THANK YOU!!!
Mikkel - The 15 year old iDeveloper! ;)

Answer 1

You are misunderstanding how table view cells work. They are not for saving state information, they are for presenting it, and interacting with the user.
When a table view cell is scrolled off-screen, the system tosses it into a recycle queue, and any field settings in the cell are lost.
When a user interacts with the controls in your table view, you should immediately save the changed information to your model (data storage). Then, when the table view asks you for a cell in the tableView:cellForRowAtIndexPath: method, you should create and FULLY configure a cell with the values from your model.

Answer 2

I found out that i forgot that i get data from my database, witch returns -1. And if I choose segment 2 and then scroll down and then back up, it show the value from the database :) This was fixable by adding a boolan to check where it should look fore the selected segment :) Now it looks like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"FancyCell"];
cell = nil;
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"FancyCell"];
cell.accessoryType = UITableViewCellAccessoryDetailDisclosureButton;
// add the segmentedControl when you create a new cell
UIImage *correctImageGreen = [[UIImage imageNamed:#"green.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
UIImage *correctImageGul = [[UIImage imageNamed:#"gul.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
UIImage *correctImageRed = [[UIImage imageNamed:#"red.png"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
NSArray *itemArray = [NSArray arrayWithObjects: correctImageGreen, correctImageGul, correctImageRed, nil];
UISegmentedControl *segmentedControl = [[UISegmentedControl alloc] initWithItems:itemArray];
segmentedControl.frame = CGRectMake(308, 8, 150, 28);
[cell.contentView addSubview:segmentedControl];
// add an action so we can change our model if the view changes
[segmentedControl addTarget:self action:#selector(didChangeSegmentedControl:) forControlEvents:UIControlEventValueChanged];
// use a tag so we can retrieve the segmentedControl later
segmentedControl.tag = 42;
}
// either if the cell could be dequeued or you created a new cell,
// segmentedControl will contain a valid instance
UISegmentedControl *segmentedControl = (UISegmentedControl *)[cell.contentView viewWithTag:42];
UIImage *comment = [UIImage imageNamed:#"Checkmark-hvid"];
UIImage *imageRef = [UIImage imageNamed:#"Checkmark-hvid"];
UIImageView *commentView = [[UIImageView alloc] initWithImage: comment];
UIImageView *imageRefView = [[UIImageView alloc] initWithImage: imageRef];
commentView.frame = CGRectMake(625, 5, 30, 30);
imageRefView.frame = CGRectMake(515, 5, 30, 30);
commentView.tag = 98;
imageRefView.tag = 99;
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
boolean_t didGetStates = [defaults boolForKey:#"didGetStates"];
boolean_t didSelectState = [defaults boolForKey:#"didSelectState"];
MBFancyObject *object = _objects[indexPath.row];
if (didGetStates) {
NSDictionary *dic = [tableData objectAtIndex:indexPath.row];
if (didSelectState) {
segmentedControl.selectedSegmentIndex = object.selectedIndex;
}
else {
int selectedState = [[dic valueForKey:#"State"] intValue];
[cell.contentView addSubview:segmentedControl];
if (selectedState == -1) {
segmentedControl.selectedSegmentIndex = -1;
}
else {
segmentedControl.selectedSegmentIndex = selectedState;
}
}
int comment = [[dic valueForKey:#"Comment"] intValue];
int imageRef = [[dic valueForKey:#"Foto"] intValue];
if (comment == 0) {
[cell.contentView addSubview:commentView];
}
else {
[[cell.contentView viewWithTag:98]removeFromSuperview];
}
if (imageRef == 0) {
[cell.contentView addSubview:imageRefView];
}
else {
[[cell.contentView viewWithTag:99]removeFromSuperview];
}
}
cell.textLabel.text = object.title;
cell.selectionStyle = UITableViewCellSelectionStyleNone;
object.selectedIndex = segmentedControl.selectedSegmentIndex;
object.currentIndexRow = indexPath.row;
cell.backgroundColor = [UIColor clearColor];
cell.textLabel.textColor = [UIColor whiteColor];
return cell;
}
And the segmentedControl's action:
- (IBAction)didChangeSegmentedControl:(UISegmentedControl *)sender {
// transform the origin of the cell to the frame of the tableView
CGPoint senderOriginInTableView = [self.tableView convertPoint:CGPointZero fromView:sender];
NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:senderOriginInTableView];
NSAssert(indexPath, #"must have a valid indexPath");
MBFancyObject *object = _objects[indexPath.row];
object.selectedIndex = sender.selectedSegmentIndex;
[[NSUserDefaults standardUserDefaults] setBool:TRUE forKey:#"didSelectState"];
}