Load DataController before ViewController iOS - ios

Question

I have 2 Controllers, 1 is to load data from JSON, the other is a simple UITableViewController. My problem is that the view is loaded before the data. How can I make the data load before my table? I'm new to Objective-C OOP :/
the code
#import "MasterViewController.h"
#import "DetailViewController.h"
#import "DealsDataController.h"
#import "Deals.h"
#implementation MasterViewController
- (void)awakeFromNib
{
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
self.clearsSelectionOnViewWillAppear = NO;
self.contentSizeForViewInPopover = CGSizeMake(320.0, 600.0);
}
[super awakeFromNib];
self.dataController = [[DealsDataController alloc] init];
NSLog(#"this is the awake from nib count %i",[self.dataController countOfList]);
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - Table View
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSLog(#"did this count the list %i",[self.dataController countOfList]);
return [self.dataController countOfList];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"DealCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
Deals *dealAtIndex = [self.dataController objectInListAtIndex:indexPath.row];
[[cell textLabel] setText:dealAtIndex.name];
return cell;
}
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the specified item to be editable.
return NO;
}
/*
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
if (editingStyle == UITableViewCellEditingStyleDelete) {
[_objects removeObjectAtIndex:indexPath.row];
[tableView deleteRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationFade];
} else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view.
}
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad) {
NSDate *object = _objects[indexPath.row];
self.detailViewController.detailItem = object;
}
}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([[segue identifier] isEqualToString:#"showDetail"]) {
NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
NSDate *object = _objects[indexPath.row];
[[segue destinationViewController] setDetailItem:object];
}
}
*/
#end
and the Data Controller
#import "DealsDataController.h"
#import "Deals.h"
#implementation DealsDataController
#synthesize masterDealsList = _masterDealsList;
-(id)init {
if (self = [super init]) {
[self initializeDataList];
return self;
}
return nil;
}
-(NSMutableArray *)masterDealsList {
if (!_masterDealsList) {
_masterDealsList = [[NSMutableArray alloc] init];
}
return _masterDealsList;
}
-(void)setMasterDealsList:(NSMutableArray *)newList {
if (_masterDealsList != newList) {
_masterDealsList = newList;
}
}
- (void)fetchedData:(NSData *)responseData {
//parse out the json data
NSError* error;
NSDictionary *json = [NSJSONSerialization
JSONObjectWithData:responseData //1
options:kNilOptions
error:&error];
_deals = [json objectForKey:#"deals"]; //2
NSLog(#"deals: %#", _deals);
NSArray *dealName = [_deals valueForKey:#"deal_name"];
NSLog(#"deals Name: %#", dealName);
for (int i = 1;i <= [_deals count]; i++) {
NSDictionary* dict = [_deals objectAtIndex:i-1];
Deals *deal =[[Deals alloc] initWithProdID:1 name:[dict valueForKey:#"deal_name"] description:[dict objectForKey:#"deal_description"] price:10.00 specs:#"specs" terms:#"terms"];
[self addDealWithDeal:deal];
NSLog (#"masterListCount %i ", [self countOfList]);
}
}
-(void)initializeDataList {
//NSDate *today = [NSDate date];
dispatch_async(sweetDealsQueue, ^{
NSData* data = [NSData dataWithContentsOfURL:sweetDealsURL];
[self performSelectorOnMainThread:#selector(fetchedData:)
withObject:data waitUntilDone:YES];
});
}
-(NSUInteger)countOfList {
return [self.masterDealsList count];
}
-(Deals *)objectInListAtIndex:(NSUInteger)theIndex {
return [self.masterDealsList objectAtIndex:theIndex];
}
-(void)addDealWithDeal:(Deals *)deal {
[self.masterDealsList addObject:deal];
}
#end

Answer 1

In MVC, you'd typically have one view controller per view. So a single view controller would be responsible for everything display on one view. Of course, you can have helper classes, or use sub view controllers (e.g. widgets), or if you're developing for iPad, you might have two view controllers (one for the side menu, one for the main view).
I'd suggest you do the following
Make your DataController a subclass of NSObject instead of UIViewController. From what I understand, it is a data access class, not responsible for UI.
In the viewDidLoad method of your MasterViewController, allocate and initialise a DataController object and trigger its data load method.
Either set a callback so when data is fetched, a method on the MasterViewController is called with the data. Or set your MasterViewController as a delegate for your DataController and when it's done, assign the data to a property of the MasterViewController.

Answer 2

i guess you need to perform Data loading before initialising your TableViewController and as you get response Data load the TableViewController. for that refer this post how to wait until some method complete execution, perform data loading in that method.

Answer 3

Its okay to display a blank tableview with an activity indicator overlay while the data is loading. When the data has finished loading, you can just reload the tableview with the data and remove the activity indicator. [tableview reloaddata] would call all of the datasource delegate methods which would then have your data in it.