CellForRowAtIndexPath not called - UITableViewCells disappear/are blank - ios

Question

Posting a specific question/answer to a specific problem (unlike the general problems with this method I've seen elsewhere):
I have a UITableView, which is a part of a custom UITableViewController, which I setup and then add to a different view controller.
My UITableView is being loaded, calls all the appropriate setup methods (e.g. numberOfRowsInSection, numberOfSectionsInTableView, etc), but cellForRowAtIndexPath is never called.
I've confirmed that the dataset is being loaded - numberOfRowsInSection is not always zero.
What gives??

Answer 1

The goal appears to be the reuse of a table view's datasource. This can be accomplished by separating the datasource from the view controller. In outline, as follows:
// MyTableViewDatasource.h
#interface MyTableViewDatasource : NSObject <UITableViewDatasource>
#property(strong,nonatomic) NSMutableArray *array;
#end
// MyTableViewDatasource.m
#import "MyTableViewDatasource.h"
#implementation MyTableViewDatasource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)s {
return self.array.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
// your cell config logic from the original view controller
// replace any mention of that vc's model array with self.array
}
#end
Now, say ViewControllerA has a tableView, and we want its datasource to be our newly defined datasource...
// ViewControllerA.m
#import "ViewControllerA.h"
#import "MyTableViewDatasource.h"
#interface ViewControllerA ()
#property(strong,nonatomic) MyTableViewDatasource *datasource;
#end
-(void)viewDidLoad {
// create our data and our datasource
// don't have to do this in viewDidLoad, but it needs to be done
// before the table can be seen, anytime after the model is ready
// this "model" in your case is whatever array that holds the data for the table
NSMutableArray *model = [#[#"Moe", #"Larry", #"Curly"] mutableCopy];
MyTableViewDatasource *datasource = [[MyTableViewDatasource alloc] init];
datasource.array = model;
self.tableView.datasource = datasource;
}
Now ViewControllerA, wherever it once modified its model array, should do the same this way...
[self.datasource.array addObject:#"Shemp"];
[self.tableView reloadData];
Hopefully it's clear that ViewControllerB and C and so on can do the same thing, replacing the code that you posted in your answer.

Answer 2

If you are using ARC, then it's very likely that your custom view controller, which is the ultimate owner of your UITableView, it being trashed as soon as you add the tableView to another view.
Try adding the UITableView's view controller to the master/other view controller's, either via a property or through the view hierarchy.
In my case, I simply created a new property for it in the view controller that wanted its table:
#property (strong, nonatomic) MyTableViewController *tvc;
and later assigned it to self when creating it:
self.tvc = [[MyTableViewController alloc] init];
[self.someOtherView addSubview:tvc.tableView];