cellForRowAtIndexPath: Is it XCode template correct? - ios

This question is about cellForRowAtIndexPath.
As I know the correct way is
UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:#"Cell"];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:#"Cell"];
return cell;
But when I created Master-Detail template, code looks like this
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell"];
[self configureCell:cell atIndexPath:indexPath];
return cell;
}
- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath
{
NSManagedObject *object = [self.fetchedResultsController objectAtIndexPath:indexPath];
cell.textLabel.text = [[object valueForKey:#"timeStamp"] description];
}
EDIT: The question is not about configureCell atIndexPath. As you see these strings absent in XCode template.
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier] ;
Is XCode template correct?

The template code is correct.
Beginning with iOS 5.0 it's possible to register a nib for a cell identifier. Whenever the table needs a cell and there are no reusable cells left it instantiates the nib and creates the cell by itself.
If you do so dequeueReusableCellWithIdentifier: always returns a cell; you don't have to create it yourself.
The API to register nibs is: registerNib:forCellReuseIdentifier:.

Related

Subtitle in dequeueReusableCellWithIdentifier

I have this code
UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
Song *song = [self.music objectAtIndex:indexPath.row];
cell.textLabel.text = song.title;
cell.detailTextLabel.text = song.artist;
return cell;
I don't use Interface Builder. How I can make this cell to have a subtitle? All I get is a standard cell.
There are two approaches:
The old style approach is to not register any class, NIB or cell prototype, call dequeueReusableCellWithIdentifier without forIndexPath:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell"];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"Cell"];
}
Song *song = self.music[indexPath.row];
cell.textLabel.text = song.title;
cell.detailTextLabel.text = song.artist;
return cell;
}
As we discussed elsewhere, this assumes that you do not register a class for that reuse identifier.
The alternative is to register your own class in viewDidLoad:
[self.tableView registerClass:[MyCell class] forCellReuseIdentifier:#"Cell"];
and then call dequeueReusableCellWithIdentifier with forIndexPath option, but lose the code that manually tests if it is nil (because it never will be nil):
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MyCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
Song *song = self.music[indexPath.row];
cell.textLabel.text = song.title;
cell.detailTextLabel.text = song.artist;
NSLog(#"title=%#; artist=%#", song.title, song.artist); // for diagnostic reasons, make sure both are not nil
return cell;
}
This obviously assumes that you've implemented a UITableViewCell subclass that includes the subtitle (note I'm overriding the style):
#interface MyCell : UITableViewCell
#end
#implementation MyCell
- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
return [super initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:reuseIdentifier];
}
#end
Personally, I think designing a cell prototype (which automatically registers the reuse identifier and takes care of all of this other stuff) is much easier. Even the old technique of registering a NIB is easier than the above. But if you want to do it entirely programmatically, those are the two approaches.
Try this in your cellForRowAtIndexPath method
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
Hope it helps.
Try this code :
UITableViewCell *cell= [self.tableView dequeueReusableCellWithIdentifier:#"Cell"];
if (cell==nil) {
// Using this way you can set the subtitle
cell=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"Cell"];
}
Song *song = [self.music objectAtIndex:indexPath.row];
cell.textLabel.text = song.title;
cell.detailTextLabel.text = song.artist;
return cell;

UITableViewCell disclosure indicator disappears on scrolling

I have a custom tableViewCell with some subviews defined in a prototype cell in a storyboard. In the storyboard I set the Accessory to Disclosure Indicator, but when scrolling (when cells are reused) the indicator disappears.
I tried to set it in code:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
...
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
It did not work as well. But I found a working solution, a very weird solution:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
...
cell.accessoryType = UITableViewCellAccessoryNone;
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
I don't know why this can fix anything, but it works for me. Can anyone tell me why or if there is an other problem/fix?
UPDATE:
How i get the reusable cell:
ActivityWeekCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
I also tried:
ActivityWeekCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
if (cell == nil) {
cell = [[ActivityWeekCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"Cell"];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
}
Try to use this variant:
ActivityWeekCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
if (cell == nil) {
cell = [[ActivityWeekCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"Cell"];
}
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

UITableViewCell subtitle not appearing on load

I have a table with cells where the subtitle only appears after something has been searched. This is the code for cellForRowAtIndexPath:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(!cell)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
}
if(tableView == self.tableView)
{
// Configure the cell...
cell.textLabel.text = self.objects[indexPath.row];
cell.detailTextLabel.text = #"test2";
}
else{
// Configure the cell...
cell.textLabel.text = self.results[indexPath.row];
cell.detailTextLabel.text = #"test1";
}
return cell;
}
EDIT: ArtOfWarfare's answer was correct. it was a problem in the storyboard. See image below:
Your code suggests that you have two separate tables... I would suggest that your problem lies within the differences in how the tables have been configured, possibly in your Storyboard.
Do you, perchance, have one of them set with a prototype with an identifier of "Cell" but a style that isn't UITableViewCellStyleSubtitle? That would make it so that your cell creation method isn't called in one, but only in the other.

Tableview subtitles on IOS7

I'm trying to add a subtitle to my tableview cells, but they are not displayed.
Where is the mistake?
Is the row
[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle]
up-to-date, also with iOS 7?
Best regards
Frank
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
if (!cell)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
cell.textLabel.text = #"TestA";
cell.detailTextLabel.text = #"TestB";
return cell;
}
This code:
if (!cell)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
will never execute because dequeueReusableCellWithIdentifier: forIndexPath: is guaranteed to allocate a new cell.
Unfortunately, registerClass:forCellReuseIdentifier: doesn't let you specify a UITableViewCellStyle.
Change dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath to simply dequeueReusableCellWithIdentifier:CellIdentifier. This method does not guarantee a cell will be returned.* When it's not, your code will then create a new cell with the style you want.
* - (It will if you're using a storyboard, as rdelmar points out, but that's not the case here.)
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = nil;
cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"cell"];
}
cell.textLabel.text = #"Title1";
cell.detailTextLabel.text = #"Subtitle 1";
return cell;
}
I had a similar problem and no solution on the internet worked for me. Turns out I was being an idiot. I'll post my solution just incase someone else experience a similar scenario.
I am assuming that you are using storyboard, have created a prototype and set the style to subtitle
In your storyboards document outline, make sure you select the protoptype cell and select the subtitle. See image:
Now ensure that the label font colour is of a nature that us visible on your background!
Simply subclass UITableViewCell and override
- (instancetype)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier;
with the first line being
[super initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:reuseIdentifier];
And register your cell class with the table view
[tableView registerClass:[YourCellSubclass class] forCellReuseIdentifier:#"YourCellID"];

UITableViewCell initWithStyle:UITableViewCellStyleSubtitle is not working

I'm having an issue in trying to display info in a cell, one on the left and one on the right. I'm aware using initWithStyle with UITableViewCellStyleSubtitle. I use this but it doesn't seem to work.
Here is some sample code:
- (UITableViewCell *)tableView:(UITableView *)ltableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Account Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:Cellidentifier];
}
Accounts *account = [self.fetchedResultsController objectAtIndexPath];
cell.textLabel.text = account.name;
cell.detailTextLabel.text = #"Price";
return cell;
}
I can display cell.textLabel.text just fine, however I cannot get the simple "Price" to be displayed. I've tried different things, such as setting the font size of cell.detailTextLabel.
I've also tried UITableViewCellStyleValue1 as some had suggested in older posts.
Threw NSLog after setting to "Price", shows cell.detailTextLabel as null.
Not sure what I'm doing wrong.
Edit: I found this: cell.detailTextLabel.text is NULL
If I remove if (cell == nil) it works...
That check should be in place, so how do you make it work when using the different styles?
When using storyboards and prototype cells, a cell is always returned from the dequeue method (assuming a prototype with that identifier exists). This means you never get into the (cell == nil) block.
In your case the prototype cell is not defined in the storyboard with the subtitle style, so a subtitled cell is never used, and the detail text label does not exist. Change the prototype in the storyboard to have the subtitle style.
Remove all your code just once you try these lines only and check this will work or not.
-(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];
}
cell.textLabel.text=[Array objectAtIndex:indexPath.row];
cell.detailTextLabel.text=#"Price";
return cell;
}
I see the problem: in your method name, the UITableView variable is named ltableView, not tableView. Change it to tableView.
cell.detailTextLable.text should be cell.detailTextLabel.text. It looks like a simple mis-spelling of label.
All the answers mentioned here are really a workaround i.e. using storyboard.
Here is a way to do it only in code.
Basically instead of registering the identifier for the cell in viewDidLoad do it only once in cellForRowAtIndexPath: method. Also reset cell registered in viewDidLoad __sCellRegistered = 0;
static int _sCellRegistered = 0;
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = nil;
if (__sCellRegistered == 0) {
__sCellRegistered = 1;
NSLog(#"register cell");
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:#"CellIdentifier"];
[self.tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:#"CellIdentifier"];
};
if (!cell) {
NSLog(#"dequeue");
cell = [tableView dequeueReusableCellWithIdentifier:#"CellIdentifier" forIndexPath:indexPath];
}

Resources