Why the dummy text can't load on my cell? - objective-c

Question

This is the tableView, as you can see, which cell, have two part, the left one, is a leftUIView, and right one, is the rightUIView. The red and green color can display, but the rightLabel I create can't show successfully. What's wrong with my code? Thank you.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *SectionsTableIdentifier = #"SectionsTableIdentifier";
UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:SectionsTableIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleSubtitle
reuseIdentifier:SectionsTableIdentifier] autorelease];
}
cell.textLabel.textColor = [UIColor whiteColor];
UIView *rightUIView = [[UIView alloc] initWithFrame:CGRectMake(160, 0, 160, cell.frame.size.height)];
[rightUIView setBackgroundColor:[UIColor greenColor]];
UIView *leftUIView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 160, cell.frame.size.height)];
[leftUIView setBackgroundColor:[UIColor redColor]];
UILabel *rightLabel = [[UILabel alloc] init];
[rightLabel setText:#"dummy"];
[rightUIView addSubview:rightLabel];
[cell addSubView:leftUIView];
[cell addSubView:rightUIView];
}

Answer 1

The first problem with your code is that you create cell's subviews each time cell is requested - if you scroll your table to and fro your cell will have a bunch of those subviews - certainly that's not good. You must create cell subviews only once - when you create the cell and after that only set appropriate values to them:
const int kRightViewTag = 100;
const int kRightLabelTag = 200;
...
if (cell == nil) {
// Create everything here
cell = [[[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleSubtitle
reuseIdentifier:SectionsTableIdentifier] autorelease];
cell.textLabel.textColor = [UIColor whiteColor];
UIView *rightUIView = [[UIView alloc] initWithFrame:CGRectMake(160, 0, 160, cell.frame.size.height)];
rightUIView.tag = kRightViewTag;
[rightUIView setBackgroundColor:[UIColor greenColor]];
[rightUIView release]; // Do not forget to release object you allocate!!
UIView *leftUIView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 160, cell.frame.size.height)];
[leftUIView setBackgroundColor:[UIColor redColor]];
[leftUIView release]; // Do not forget to release object you allocate!!
UILabel *rightLabel = [[UILabel alloc] initWithFrame:leftUIView.bounds];
rightLabel.tag = kRightLabelTag;
[rightUIView addSubview:rightLabel];
[rightLabel release];
}
// Setup values here
UILabel* rightLabel = (UILabel*)[[cell viewWithTag:kRightViewTag] viewWithTag:kRightLabelTag];
rightLabel.text = #"dummy";
The second thing is you do not set label's frame anywhere (I've fixed that above) so it is likely has zero-sized frame and that's why you cannot see it.
The 3rd problem is that you allocate views but don't release them - so they just leak. Do not forget that if you create some objects using alloc, new or copy then you're responsible for releasing them.