CODEWITHSUNDEEP
iphoneobjective-ciosuitableview
Azhar
Azhar

Reputation: 20670

UILabel value does not update in cellForRowAtIndexPath?

I am creating custom cells and updating some UILabels every time when that view appears.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{

       UILabel *lblFacingValue = nil;
       static NSUInteger const kFacingLabelTag = 7;

      CGFloat LeftLabelWidth = 130.0;

      static NSString *CellIdentifier = @"Cell";
      ClientState *clientState = [ClientState sharedInstance];
      UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

   if (cell == nil) 
   {
       cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];

       if(indexPath.row == 0)
       {
           lblFacingValue = [[[UILabel alloc] initWithFrame:CGRectMake(246, -11, LeftLabelWidth, (cell.contentView.frame.size.height))] autorelease];
           lblFacingValue.font = [UIFont systemFontOfSize:21];           
           lblFacingValue.textAlignment = UITextAlignmentLeft;
           lblFacingValue.backgroundColor = [UIColor clearColor];
           lblFacingValue.tag = kFacingLabelTag;        
           lblFacingValue.textColor = [UIColor yellowColor];
           [cell.contentView addSubview:lblFacingValue];
       }
    }
   lblFacingValue.text = [NSString stringWithFormat:@"%@", clientState.Direction];
}

But the problem is that it contains the value which I assign first time and do not update it when I open that view. that view is in tab.

It did not update the value of lblFacingValue and skip the check

if (cell == nil)

after first time. but do not update lblFacingValue.

Upvotes: 0

Views: 1344

Answers (4)

Almer Lucke
Almer Lucke

Reputation: 241

Azhar, I think you forget to set the lblFacingValue variable to the actual UILabel object when the call to dequeueReusableCellWithIdentifier does not return nil. You should add:

lblFacingValue = [cell viewWithTag:kFacingLabelTag];

before calling

lblFacingValue.text = [NSString stringWithFormat:@"%@", clientState.Direction];

Hope this helps!

Upvotes: 3

dbgrman
dbgrman

Reputation: 5681

Keep one thing in mind, when cell is nil, you construct the cell. Don't assign values there. Just create subviews etc.

This code should fix it. Also see my comments in it.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{   
    static NSUInteger const kFacingLabelTag = 7; //This should rather be a #define ..   
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
   if (cell == nil) {
       cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];

       if(indexPath.row == 0)
       {
           CGFloat LeftLabelWidth = 130.0;
           UILabel *lblFacingValue = [[[UILabel alloc] initWithFrame:CGRectMake(246, -11, LeftLabelWidth, (cell.contentView.frame.size.height))] autorelease];
           lblFacingValue.font = [UIFont systemFontOfSize:21];           
           lblFacingValue.textAlignment = UITextAlignmentLeft;
           lblFacingValue.backgroundColor = [UIColor clearColor];
           lblFacingValue.tag = kFacingLabelTag;        
           lblFacingValue.textColor = [UIColor yellowColor];
           [cell.contentView addSubview:lblFacingValue];
       }
    }

    //now, we might be reusing the cell, so in either case, pick the label
    //and edit the value.

    ClientState *clientState = [ClientState sharedInstance];
    UILabel *theLabel = (UILabel*) [cell.contentView viewForTag:kFacingLabelTag];    
    theLabel.text = [NSString stringWithFormat:@"%@", clientState.Direction];
}

Upvotes: 2

jbat100
jbat100

Reputation: 16827

The problem is that your specially configured cell has the same cell identifier as the others,

static NSString *CellIdentifier = @"Cell";

So the system doesn't differentiate when dequeuing cells between your special cell and normal cells. You should create a different cell identifier for the special cell, and dequeue using that when indexPath.row == 0;

Upvotes: 0

rckoenes
rckoenes

Reputation: 69469

You forget a piece where you get the label by it tag if you do dequeue a cell.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{

    UILabel *lblFacingValue = nil;
    static NSUInteger const kFacingLabelTag = 7;

    CGFloat LeftLabelWidth = 130.0;

    static NSString *CellIdentifier = @"Cell";
    ClientState *clientState = [ClientState sharedInstance];
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) 
    {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];

        if(indexPath.row == 0)
        {
            lblFacingValue = [[[UILabel alloc] initWithFrame:CGRectMake(246, -11, LeftLabelWidth, (cell.contentView.frame.size.height))] autorelease];
            lblFacingValue.font = [UIFont systemFontOfSize:21];           
            lblFacingValue.textAlignment = UITextAlignmentLeft;
            lblFacingValue.backgroundColor = [UIColor clearColor];
            lblFacingValue.tag = kFacingLabelTag;        
            lblFacingValue.textColor = [UIColor yellowColor];
            [cell.contentView addSubview:lblFacingValue];
        }
    } else {
        lblFacingValue = [cell.contentView viewWithTag:kFacingLabelTag];
    }

    lblFacingValue.text = [NSString stringWithFormat:@"%@", clientState.Direction];
}

Upvotes: 1

Related Questions