_tableView reloadData not working when i called method from another class - ios

Question

This table view is working fine when tableview is firstly loaded
but when I tried to reload data using [_tableView reloadData], suddenly list won't reload at all.
Here's code:
-(void)loadListLoop{
AppDelegate* delegate = [[UIApplication sharedApplication] delegate];
shuffleLbl.hidden=false;
[self.view bringSubviewToFront:shuffleLbl];
NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
NSString*playlistID=delegate.gPlaylistID;
NSString*token=[ud stringForKey:#"youtube_token"];
NSString *origin = [NSString stringWithFormat: #"https://www.googleapis.com/youtube/v3/playlistItems?part=snippet&maxResults=50&playlistId=%#&key=AIzaSyBeFK_llQHRl7TyXoQxGkLDmIfKGzOPezM&access_token=%#",playlistID,token];
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:origin]];
NSData *json = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];
NSArray *array = [NSJSONSerialization JSONObjectWithData:json options:NSJSONReadingAllowFragments error:nil];
_titleList=[array valueForKeyPath:#"items.snippet.title"];
_thumbnailList=[array valueForKeyPath:#"items.snippet.thumbnails.default.url"];
_idList=[array valueForKeyPath:#"items.snippet.resourceId.videoId"];
NSLog(#"%#",_titleList);
[[NSRunLoop currentRunLoop]runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0.5]];
dispatch_sync(dispatch_get_main_queue(), ^{
[_tableView reloadData];
});
}
The method loadListLoop is called from another class using:
PlaylistDetailViewController *playlistDetail = [[PlaylistDetailViewController alloc] init];
[playlistDetail loadList];
Looks like loadListLoop is successfully called and everything before [_tableView reloadData]; is also successfully loaded.
I put NSLog inside - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
to see is app is at least trying to reload data but it seems its not working at all.
EDIT:
first,view controller that contains "-(void)loadListLoop" is container view.so target view controller should be on screen
EDIT2:
i defined outlet at .h file below
#import <UIKit/UIKit.h>
#interface PlaylistDetailViewController : UIViewController<UITableViewDelegate, UITableViewDataSource>{
//IBOutlet UITableView *tableView;
IBOutlet UIButton *shuffleLbl;
}
-(void)exitLoopVoid;
-(void)loadListLoop;
#property (nonatomic,strong) IBOutlet UITableView *tableView;
#property (nonatomic,retain) NSMutableArray *titleList;
#property (nonatomic,retain) NSMutableArray *authorList;
#property (nonatomic,retain) NSMutableArray *thumbnailList;
#property (nonatomic,retain) NSMutableArray *idList;
-(IBAction)shuffle;
#end
IMPORTANT
EDIT3:
looks like some thing very weird is happening to NSMutableArray.
overwrite NSMutableArray at loadListLoop method(works fine and checked content with NSLog)
reload table(seems this is working fine too)
content inside NSMutableArray will rollback to old content
anyone has idea about this issue?
EDIT4:
1.overwrite NSMutableArray at loadListLoop method(success)
2.reload table and NSMutableArray will be null only at this method
3.rollback to data that i overwrites data at loadListLoop

Answer 1

I see a couple of problems.
First, the code you posted is a method loadListLoop. But the code that you posted is calling a different method loadList. The two are not connected.
Second, you say:
the method "loadListLoop" is called from another class using
PlaylistDetailViewController *playlistDetail =
[[PlaylistDetailViewController alloc] init];
[playlistDetail loadList];
That code is very wrong. It is creating a brand new instance of PlaylistDetailViewController that is not on-screen, and invoking the loadList method on that newly created view controller.
The view controller hasn't had a chance to display itself yet, so it's view properties will be nil. Plus, the view controller probably doesn't have any data in the model structure it uses to populate it's table view, so it won't have anything to display.
Further, if your view controller's view structure is defined in a storyboard, you can't use alloc/init to create new view controller instances.
At the point where you're trying to call loadList/loadListLoop, is the target view controller on screen? You need to explain your calling sequence.

Answer 2

use NSNotificationCenter for Update the table from one class to another class
1.do this in from where you have to call.
[[NSNotificationCenter defaultCenter] postNotificationName: #"UpdateTable" object:nil userInfo:userInfo];
2.And use this one for table view class. Write this in ViewDidLoad method.
[[NSNotificationCenter defaultCenter]addObserver:self
selector:#selector(refresh_method)
name:#"UpdateTable"
object:nil];
3.
-(void)refresh_method
{
//reload table here.
}