UITableView reloading data / refreshing (possible duplication issue) - iphone

Question

I have a UITableView in an iPhone application which I am refreshing (by calling [self.tableView reloadData] in the action method for a UISegmentedControl dynamically embedded in one of the UITableView cells. The table view is refreshed to update a text value for one of the cells.
However, the following code seems to produce an unwanted side-effect. It appears that each time the UITableView refreshes it creates a new instance of the UISegmentedControl (and possibly the images - I'm not sure) over the existing one(s).
The only reason I notice this is that with each refresh a barely perceptible border starts to form around the UISegmentedControl and the application slows noticeably. I would be extremely grateful for any suggestions/code-solutions to my current predicament.
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
}
NSUInteger section = indexPath.section;
NSUInteger row = indexPath.row;
// Set up the cell...
//populates the personal info section
if (section == kPersonalInfoAddSection) {
if (row == kNameRow) {
//Other code irrelevant to this question was removed for the sake of clarity
}
else if(row == kHeightRow) {
cell.imageView.image = [UIImage imageNamed:#"tableview_height_label.png"];
//THIS IS THE TEXT I'M TRYING TO UPDATE
cell.textLabel.text = [Formatter formatHeightValue:mainUser.heightInMM forZone:self.heightZone];
cell.detailTextLabel.text = REQUIRED_STRING;
}
}
//populates the units section
if (section == kUnitsSection) {
if (row == kHeightUnitsRow) {
NSArray *heightUnitsSegments = [[NSArray alloc] initWithObjects:FT_AND_IN_STRING, M_AND_CM_STRING, nil];
UISegmentedControl *heightUnitControl = [[UISegmentedControl alloc] initWithItems:heightUnitsSegments];
CGRect segmentRect = CGRectMake(90, 7, 200, 30);
[heightUnitControl setFrame:segmentRect];
//[heightUnitControl setSelectedSegmentIndex:0];
[heightUnitControl addTarget:self action:#selector(heightSegmentClicked:) forControlEvents:UIControlEventValueChanged];
heightUnitControl.tag = kHeightSegmentedControlTag;
cell.textLabel.text = #"Height:";
cell.detailTextLabel.text = #"(units)";
[cell.contentView addSubview:heightUnitControl];
[heightUnitsSegments release];
[heightUnitControl release];
}
else if(row == kWeightUnitsRow) {
//Other code irrelevant to this question was removed for the sake of clarity
}
}
return cell;
}
Thank you all in advance!

Answer 1

You're right, it is creating a new instance of the UISegmentedControl. It's because you are using a generic cell identifier, #"Cell", then adding the UISegmentedControl each time, never removing it. The cells get cached containing the UISegmentedControl, you retrieve the cached cell and add the control again.
You could use a more specific cell identifier and if cell != nil you know it contains the UISegmentedControl already. Or create a new cell each time that way you're not using a cached cell that already contains the control.
With the image view you just set the cells image view property without adding a new view to the cell so that one is ok, it gets replaced each time.
Since the text you are trying to update doesn't have to do with the UISegmentedControl I think you should be able to use a more specific cell identifier and add the control only on cell creation.

Answer 2

- (void)viewDidLoad {
[super viewDidLoad];
NSArray *arr1=[NSArray arrayWithObjects:#"img1.jpg",#"img2.jpg",nil];
NSArray *arr2=[NSArray arrayWithObjects:#"img1.jpg",#"img2.jpg",#"img3.jpg",#"img4.jpg",#"img5.jpg",#"img6.jpg",nil];
NSArray *arr3=[NSArray arrayWithObjects:#"img6.jpg",#"img5.jpg",#"img2.jpg",#"img1.jpg",nil];
Imgs = [[NSArray alloc] initWithArray:[NSArray arrayWithObjects:arr1,arr2,arr3,nil]];
NSDictionary *dic1=[NSDictionary dictionaryWithObjectsAndKeys:#"Ahmedabad",#"Name",#"Picture 5.png",#"Rating",#"Picture 1.png",#"Photo",arr1,#"img",nil];
NSDictionary *dic2=[NSDictionary dictionaryWithObjectsAndKeys:#"Rajkot",#"Name",#"Picture 5.png",#"Rating",#"Picture 2.png",#"Photo",nil];
NSDictionary *dic3=[NSDictionary dictionaryWithObjectsAndKeys:#"Baroda",#"Name",#"Picture 5.png",#"Rating",#"Picture 7.png",#"Photo",nil];
tblArray=[[NSArray alloc] initWithObjects:dic1,dic2,dic3,nil];
[myTbl reloadData];
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
self.navigationController.navigationBarHidden=NO;
[self.navigationController.navigationBar setUserInteractionEnabled:YES];
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
self.navigationController.navigationBarHidden=YES;
}
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
return 1;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return [tblArray count];
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
NSString *CellIdentifer=[NSString stringWithFormat:#"%i",indexPath.row];
UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:CellIdentifer];
if(cell==nil){
cell=[self myCustomCell:CellIdentifer dicToSet:[tblArray objectAtIndex:indexPath.row]];
[cell setAccessoryType:UITableViewCellAccessoryDisclosureIndicator];
}
return cell;
}
-(UITableViewCell*)myCustomCell:(NSString*)CellIdentifer dicToSet:(NSDictionary*)dicToSet{
UITableViewCell *cell=[[[UITableViewCell alloc] initWithFrame:CGRectMake(0, 0, 320, 44) reuseIdentifier:CellIdentifer] autorelease];
UIImageView *imgV=[[UIImageView alloc] initWithFrame:CGRectMake(2, 2, 40, 40)];
[imgV setImage:[UIImage imageNamed:[dicToSet valueForKey:#"Photo"]]];
[cell addSubview:imgV];
[imgV release];
UILabel *lbl=[[UILabel alloc] initWithFrame:CGRectMake(44, 2, 276, 20)];
[lbl setText:[dicToSet valueForKey:#"Name"]];
[cell addSubview:lbl];
[lbl setBackgroundColor:[UIColor clearColor]];
[lbl setFont:[UIFont fontWithName:#"Helvetica-Bold" size:18]];
[lbl release];
UIImageView *imgV1=[[UIImageView alloc] initWithFrame:CGRectMake(44, 24, 70, 20)];
[imgV1 setImage:[UIImage imageNamed:[dicToSet valueForKey:#"Rating"]]];
[cell addSubview:imgV1];
[imgV1 release];
return cell;
}
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
nxtPlcDtl=[[plcFullDtl alloc] initWithNibName:#"plcFullDtl" bundle:nil];
nxtPlcDtl.dict=[[NSDictionary alloc] initWithDictionary:[tblArray objectAtIndex:indexPath.row]];
nxtPlcDtl.Imgs = [Imgs objectAtIndex:indexPath.row];
nxtPlcDtl.comment1 = [comment1 objectAtIndex:indexPath.row];
nxtPlcDtl.vedio = [vedio objectAtIndex:indexPath.row];
[self.navigationController pushViewController:nxtPlcDtl animated:YES];
}