UITableViewCell row disorder - iphone

Question

I posted some question with same source code before. I just found out some other strange thing.The thing is that If I define reuse cell identifier, each row color is weird.
But If I don't use reuse identifier, its working.
Please give me any tips why each row color does not keep the order.
//its working
static NSString *CellIdentifier = #"Cell";
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"Cell"] autorelease]
cell.contentView.backgroundColor = (indexPath.row %2) ? [UIColor redColor] : [UIColor yellowColor];
//it does not work.
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; -- does not working.
cell.contentView.backgroundColor = (indexPath.row %2) ? [UIColor redColor] : [UIColor yellowColor];
- (void)viewDidLoad {
[super viewDidLoad];
//Initialize the array.
listOfItems = [[NSMutableArray alloc] init];
//Add items
[listOfItems addObject:#"1"];
[listOfItems addObject:#"2"];
[listOfItems addObject:#"3"];
[listOfItems addObject:#"4"];
[listOfItems addObject:#"5"];
[listOfItems addObject:#"6"];
[listOfItems addObject:#"7"];
[listOfItems addObject:#"8"];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning]; // Releases the view if it doesn't have a superview
// Release anything that's not essential, such as cached data
}
#pragma mark Table view methods
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [listOfItems count];
}
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UILabel *aLabel; UILabel *bLabel; UILabel *v1Label; UILabel *v2Label;; UIView *v1; UIView *v2;
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
NSLog(#" cell null");
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.contentView.backgroundColor = (indexPath.row %2) ? [UIColor redColor] : [UIColor yellowColor];
aLabel = [[[UILabel alloc] initWithFrame:CGRectMake(9.0, 8.0, 50.0, 20.0)] autorelease];
aLabel.tag = 1;
aLabel.font = [UIFont systemFontOfSize:30];
[cell.contentView addSubview:aLabel];
v1 = [[UIView alloc] initWithFrame:CGRectMake(0, 44, 320, 116)];
v1.backgroundColor = [UIColor whiteColor];
v1.tag = 10;
v1.hidden = YES;
[cell.contentView addSubview:v1];
[v1 release];
UILabel *a = [[[UILabel alloc] initWithFrame:CGRectMake(0, 10, 100, 100)] autorelease];
a.text = #"v1.test1";
[v1 addSubview:a];
UILabel *b = [[[UILabel alloc] initWithFrame:CGRectMake(0, 40, 100, 100)] autorelease];
b.text = #"v1.test2";
[v1 addSubview:b];
v2 = [[UIView alloc] initWithFrame:CGRectMake(0, 44, 320, 100)];
v2.backgroundColor = [UIColor blueColor];
v2.tag = 11;
v2.hidden = YES;
[cell.contentView addSubview:v2];
[v2 release];
UILabel *c = [[[UILabel alloc] initWithFrame:CGRectMake(0, 10, 100, 100)] autorelease];
c.text = #"v2.test1";
[v2 addSubview:c];
UILabel *d = [[[UILabel alloc] initWithFrame:CGRectMake(0, 40, 100, 100)] autorelease];
d.text = #"v2.test2";
[v2 addSubview:d];
}
else {
aLabel = (UILabel *)[cell.contentView viewWithTag:1];
//
v1 = (UIView *) [cell.contentView viewWithTag:10];
v2 = (UIView *) [cell.contentView viewWithTag:11];
}
aLabel.text = [listOfItems objectAtIndex:indexPath.row];
if (SelectedIndexPath == indexPath.row)
{
if ([aLabel.text intValue] % 2) {
v1.hidden = NO;
v2.hidden = YES;
}
else {
v1.hidden = YES;
v2.hidden = NO;
}
}
else {
v1.hidden = YES;
v2.hidden = YES;
}
return cell;
}
-(CGFloat) tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (SelectedIndexPath == indexPath.row)
{
return 162.0;
}
else {
return 46.0;
}
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if (SelectedIndexPath == -1)
{
OldSelectedIndexPath = indexPath.row;
SelectedIndexPath = indexPath.row;
[tableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath, nil] withRowAnimation:NO];
}
else
{
if (SelectedIndexPath == indexPath.row)
{
OldSelectedIndexPath = SelectedIndexPath;
SelectedIndexPath = -1;
[tableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath, nil] withRowAnimation:NO];
}
else
{
SelectedIndexPath = indexPath.row;
[tableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:[NSIndexPath indexPathForRow:OldSelectedIndexPath inSection:indexPath.section], indexPath, nil] withRowAnimation:NO];
OldSelectedIndexPath = SelectedIndexPath;
}
}
}

Answer 1

Move the coloring code outside of the if (cell == nil) { block. Just because a cell was created for an even-numbered index doesn't mean it will only be reused for even ones.
Here's a simple example of code for coloring cells that are being reused:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 20;
}
- (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];
}
cell.textLabel.text = #"Anything";
cell.contentView.backgroundColor = (indexPath.row %2) ? [UIColor redColor] : [UIColor yellowColor];
return cell;
}