how to pass data from a UIVIewController to a TableView subview? - ios

Question

I am new to ios programming, and I am trying to write a view controller that will display a question (via a label) at the top of the view and then a list of answers in a tableview subview below. The view is set up with interface builder, but I add the tableview programmatically.
I am able to load the data from a JSON source and print it out with a swipe gesture, but the data cannot be accessed inside my table view. I know from putting NSLog's that the numberOfRowsInSection runs once at the beginning to return 0 but does not run again when I invoke [self.tableView reloadData], which means the table still thinks it has 0 rows even though it should have about 20. I do set the UIViewController as the table view delegate and data source. What else do I need to do?
MAIN QUESTION: How can I access the view controller's NSMutablearray property inside my table view functions when that table view is a subview of my view controller? Thank you!
Here's my initial declarations and setup:
#interface BNRJudgeViewController () <UITextFieldDelegate, UINavigationControllerDelegate, UIGestureRecognizerDelegate, UITableViewDataSource, UITableViewDelegate >
#property (nonatomic, strong) NSURLSession *session;
#property (weak, nonatomic) IBOutlet UILabel *question;
#property (weak, nonatomic) UITableView *tableView;
#property (nonatomic) NSMutableArray *answerArray;
#end
#implementation BNRJudgeViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if ([self isKindOfClass:[UIViewController class]]) {
if(self){
// Custom initialization
self.title=#"Judge";
self.navigationController.navigationItem.title = #"Judge";
self.answerArray = [[NSMutableArray alloc] init];
NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
_session = [NSURLSession sessionWithConfiguration:config delegate:nil delegateQueue:nil];
CGRect frame = CGRectMake(61, 252, 200, 225);
UITableView *tableView = [[UITableView alloc] initWithFrame:frame];
tableView.delegate = self;
tableView.dataSource = self;
[self.view addSubview:tableView];
}
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
if ([self isKindOfClass:[UIViewController class]]) {
[self fetchFeed];
}
UISwipeGestureRecognizer *rightSwipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(swipeRight:)];
rightSwipe.direction = UISwipeGestureRecognizerDirectionRight;
rightSwipe.numberOfTouchesRequired = 1;
[self.view addGestureRecognizer:rightSwipe];
UISwipeGestureRecognizer *leftSwipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:#selector(swipeLeft:)];
leftSwipe.direction = UISwipeGestureRecognizerDirectionLeft;
leftSwipe.numberOfTouchesRequired = 1;
[self.view addGestureRecognizer:leftSwipe];
}
Here's where I fetch the JSON data and assign it to an NSMutableArray property of my view controller:
- (void)fetchFeed
{
NSString *requestString = #"http://wsomeurl";
NSURL *url = [NSURL URLWithString:requestString];
NSURLRequest *req = [NSURLRequest requestWithURL:url];
NSURLSessionDataTask *dataTask =
[self.session dataTaskWithRequest:req completionHandler:
^(NSData *data, NSURLResponse *response, NSError *error){
NSMutableArray *jsonObject = [NSJSONSerialization JSONObjectWithData:data
options:0
error:nil];
self.answerArray = jsonObject;
// NSLog(#"%#", self.answerArray);
dispatch_async(dispatch_get_main_queue(), ^{
[self.tableView reloadData];
});
}];
[self.tableView reloadData];
[dataTask resume];
[self.tableView reloadData];
}
Here are my tableview required functions, implemented in my view controller:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSLog(#"recent integer count is %d", [self.answerArray count]);
return [self.answerArray count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"UITableViewCell"];
// NSDictionary *cellD = self.answerArray[indexPath.row];
NSLog(#"%#", self.answerArray);
NSLog(#"hi hi!");
// NSLog(#"%#", [cellD objectForKey:#"username"]);
// cell.textLabel.text = [cellD objectForKey:#"username"];
return cell;
}
And finally here are some swipe functions showing that those functions can see the array - it's just the table view functions that aren't.
- (void)swipeRight:(UISwipeGestureRecognizer *) gr
{
NSLog(#"right swipe worked");
NSLog(#"right swipe array count is %d", [self.answerArray count]);
}
- (void)swipeLeft:(UISwipeGestureRecognizer *) gr
{
NSLog(#"left swipe worked");
NSLog(#"left swipe array count is %d", [self.answerArray count]);
}
Sorry for the long post. Again, MAIN QUESTION: How can I access the view controller's NSMutablearray property inside my table view functions? Thank you!
Extra technique related questions/comments...I recoded this making a custom tableviewcontroller class to load this data and have the right size and location and then initialize this tableview controller class within my view controller and put its view as a subview. But I don't want to be passing data between two view controllers because I'd like to update both the view and the subview with a swipe on the view as cleanly as possible...but might this be the better way to go?
Two related technique questions as well. First would it make more sense to stuff this information into a singleton class that I can access from any view controller? Second, would it make more sense to write some protocol (haven't done this, just know of it) to pass the information force reload in the right place?) As a newbie, I see both of these as sloppier than just sticking with one view controller as I'm trying to do, but I might just not understand objective c very well yet. Thanks in advance.

Answer 1

You have UITableView *tableView = [[UITableView alloc] initWithFrame:frame]; in your init method, so tableView is a local variable. Elsewhere you have [self.tableView reloadData], but you've never assigned your property to the table view, so self.tableView is nil. You should change the code in your init method to,
_tableView = [[UITableView alloc] initWithFrame:frame];
_tableView.delegate = self;
_tableView.dataSource = self;
[self.view addSubview:_tableView];