Why are my cells appearing blank in my UITableView? - ios

Question

I have a little bit of an odd structure for my UITableView. Basically, I have ArticleCell objects (subclass of UITableViewCell) that make up the table, and each ArticleCell is comprised of a "front" view and a "back" view. The front view has all the labels and whatnot the user sees, while the back has two icons to the left and right. This two view idea is so the user can slide the top view to the right or left to quickly select an option (kind of like in Reeder).
I've implemented this slightly in the storyboard, but mostly in code. The only thing I did in the storyboard was have the layout of the UITableViewController done, and I named the identifier for the prototype cell (identifier: "ArticleCell").
Other than the storyboard, as I said, everything's done in code. I get the cell's information from Core Data, and construct the cell by setting the article to the cell's article property, which then sets that article to CellFront UIView's article property. Because there's two kinds of cell layouts depending on the type of article the cell holds, in CellFront it checks when kind of cell it is (a property called isUserAddedText) and creates the layout accordingly.
But as I said, nothing's showing up when the app loads, all the cells load and I can tap them to go to their content, but the cells themselves are blank.
The relevant code is as follows:
Cell Data Source:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
ArticleInfo *articleInfo = [self.fetchedResultsController objectAtIndexPath:indexPath];
static NSString *CellIdentifier = #"ArticleCell";
ArticleCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[ArticleCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
cell.article = articleInfo;
return cell;
}
In ArticleCell.m, I overrode article's set method so when the data source method above calls it, it could set the view's article property as well.
- (void)setArticle:(ArticleInfo *)article {
_article = article;
self.cellFront.article = article;
}
I also created the CellFront and CellBack UIViews in the ArticleCell.m file:
- (void)awakeFromNib {
[super awakeFromNib];
self.cellBack = [[CellBack alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, 80)];
[self.contentView addSubview:self.cellBack];
self.cellFront = [[CellFront alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, 80)];
[self.contentView addSubview:self.cellFront];
}
CellFront.m then calls the following method inside its initWithFrame: method, which sets up the labels depending on the kind of article and adds them to the subview.
- (void)addControlsToView {
if ([self.article.isUserAddedText isEqualToNumber:#YES]) {
UILabel *preview = [[UILabel alloc] initWithFrame:CGRectMake(20, 5, 280, 70)];
preview.text = self.article.preview;
preview.numberOfLines = 4;
preview.font = [UIFont systemFontOfSize:16.0f];
preview.textColor = [UIColor blackColor];
preview.backgroundColor = [UIColor clearColor];
[self addSubview:preview];
}
else {
UILabel *title = [[UILabel alloc] initWithFrame:CGRectMake(20, 10, 280, 20)];
title.text = self.article.title;
title.font = [UIFont boldSystemFontOfSize:18.0f];
title.textColor = [UIColor blackColor];
title.backgroundColor = [UIColor clearColor];
[self addSubview:title];
UILabel *URL = [[UILabel alloc] initWithFrame:CGRectMake(20, 35, 280, 20)];
URL.text = self.article.url;
URL.font = [UIFont systemFontOfSize:16.0f];
URL.textColor = [UIColor blackColor];
URL.backgroundColor = [UIColor clearColor];
[self addSubview:URL];
UILabel *preview = [[UILabel alloc] initWithFrame:CGRectMake(20, 60, 280, 40)];
preview.text = self.article.preview;
preview.numberOfLines = 2;
preview.font = [UIFont systemFontOfSize:16.0f];
preview.textColor = [UIColor grayColor];
preview.backgroundColor = [UIColor clearColor];
[self addSubview:preview];
}
}
That's everything I thought would be relevant to include. Why exactly are all the cells showing up blank?

Answer 1

If you are not using storyboard or NIB's to define your views, awakeFromNib: will never be called.
Here is some documentation
You should try overriding initWithStyle:reuseIdentifier: instead of awakeFromNib:
- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self != nil) {
// DO STUFF
}
return self;
}
If you are trying to use a storyboard then you are dequeueing the cells incorrectly, replace:
ArticleCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[ArticleCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
With:
ArticleCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
This method will initialize a new cell from the storyboard if there is not one in the queue. The method you were using won't. This means that cell will equal nil sometimes, then you initialize a new cell with the initWithStyle:reuseIdentifier: method, which will not call the awakeFromNib because you are not decoding it from the NIB.
Here is a link to the documentation for this method.
Additional Information
You will also not see the data in the cell because you are setting the label text values in the same block of code that you using to initialize the views. Basically, you need to do:
...
preview.text = self.article.preview;
...
...this part of the addControlsToView method every time the cell is reused, and the initialization of the UILabel only once. I would move the above code into a setter for the article property on CellFront. For example, first declare some properties for the labels
#property (nonatomic, strong) UILabel *preview1Label;
#property (nonatomic, strong) UILabel *titleLabel;
#property (nonatomic, strong) UILabel *URLLabel;
#property (nonatomic, strong) UILabel *preview2Label;
Then something like this to initialize the controls
- (void)initControls {
self.preview1 = [[UILabel alloc] initWithFrame:CGRectMake(20, 5, 280, 70)];
self.preview1.text = self.article.preview;
self.preview1.numberOfLines = 4;
self.preview1.font = [UIFont systemFontOfSize:16.0f];
self.preview1.textColor = [UIColor blackColor];
self.preview1.backgroundColor = [UIColor clearColor];
[self addSubview:self.preview1];
self.title = [[UILabel alloc] initWithFrame:CGRectMake(20, 10, 280, 20)];
self.title.text = self.article.title;
self.title.font = [UIFont boldSystemFontOfSize:18.0f];
self.title.textColor = [UIColor blackColor];
self.title.backgroundColor = [UIColor clearColor];
[self addSubview:self.title];
self.URL = [[UILabel alloc] initWithFrame:CGRectMake(20, 35, 280, 20)];
self.URL.text = self.article.url;
self.URL.font = [UIFont systemFontOfSize:16.0f];
self.URL.textColor = [UIColor blackColor];
self.URL.backgroundColor = [UIColor clearColor];
[self addSubview:self.URL];
self.preview2 = [[UILabel alloc] initWithFrame:CGRectMake(20, 60, 280, 40)];
self.preview2.text = self.article.preview;
self.preview2.numberOfLines = 2;
self.preview2.font = [UIFont systemFontOfSize:16.0f];
self.preview2.textColor = [UIColor grayColor];
self.preview2.backgroundColor = [UIColor clearColor];
[self addSubview:self.preview2];
}
Then something like this to set the controls, likely from the setter of the article property.
- (void)setControls {
if ([self.article.isUserAddedText isEqualToNumber:#YES]) {
self.preview1.hidden = NO;
self.preview1.text = self.article.preview;
self.title.hidden = YES;
self.title.text = nil;
self.URL.hidden = YES;
self.URL.text = nil;
self.preview2.hidden = YES;
self.preview2.text = nil;
}
else {
self.preview1.hidden = YES;
self.preview1.text = nil;
self.title.hidden = NO;
self.title.text = self.article.title;
self.URL.hidden = NO;
self.URL.text = self.article.url;
self.preview2.hidden = NO;
self.preview2.text = self.article.preview;
}
}