How to display updated multiple NStimer value in Tableview cell iOS?

Question

I want to set multiple running timer value in tableview so user easily checked how many time is remaining and stop any specific timer.

Multiple Timer Start and updated value display in NSLog perfectly. User set NSTimer for particular recipe. Now suppose user set timer for recipe1 in recipedetail and now back from that recipedetail. Then again set timer for recipe2 in recipedetail and back from that recipedetail. and i want to All timer value display in UITableView. And tableview placed on recipedetail screen.

So my point is TimerUpdated value display in NSLog but not display in tableview because every Recipedetails screen generate new object of UITableView So value is not updated perfactly

 -(IBAction)okBtn:(id)sender
    {
       [self countdownTimer];
    }
-(void)countdownTimer {

        [[NSUserDefaults standardUserDefaults]setObject:recipeboxId forKey:[NSString stringWithFormat:@"timer_%@",recipeboxId]];
        [[NSUserDefaults standardUserDefaults]synchronize];
        // set timer

        [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:nil];
        (theAppDelegate).timer = [NSTimer scheduledTimerWithTimeInterval:0.6f
                                                 target:self
                                               selector:@selector(updateCounter:)
                                               userInfo:recipeboxId
                                                repeats:YES];
        [(theAppDelegate).timer fire];
    //    [[NSRunLoop currentRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];//Timer run in background

        [self CreateLocalNotification];
    }


    -(void)calculateTimeFromPicker
    {
        NSString *hoursStr = [NSString stringWithFormat:@"%@",[hoursArray objectAtIndex:[self.picker_timer selectedRowInComponent:0]]];
        NSString *minsStr = [NSString stringWithFormat:@"%@",[minsArray objectAtIndex:[self.picker_timer selectedRowInComponent:1]]];
        NSString *secsStr = [NSString stringWithFormat:@"%@",[secsArray objectAtIndex:[self.picker_timer selectedRowInComponent:2]]];

        int hoursInt = [hoursStr intValue];
        int minsInt = [minsStr intValue];
        int secsInt = [secsStr intValue];

        interval = secsInt + (minsInt*60) + (hoursInt*3600);
        secondsLeft=interval;
    }
    - (void)updateCounter:(NSTimer *)theTimer {
        if(secondsLeft > 0 )
        {
            secondsLeft -- ;
            hours = secondsLeft / 3600;
            minutes = (secondsLeft % 3600) / 60;
            seconds = (secondsLeft %3600) % 60;

            [[NSUserDefaults standardUserDefaults]setInteger:secondsLeft forKey:[NSString stringWithFormat:@"secondsLeft_%@",recipeboxId]];
            [[NSUserDefaults standardUserDefaults]synchronize];

            NSLog(@"timer :%@",[NSString stringWithFormat:@"%02d:%02d:%02d", hours, minutes, seconds]);
            NSString *timer_updated_value=[NSString stringWithFormat:@"%02d:%02d:%02d", hours, minutes, seconds];
            [[NSUserDefaults standardUserDefaults]setObject:timer_updated_value forKey:[NSString stringWithFormat:@"updated_timer_%@",[(theAppDelegate).timer userInfo]]];
            [[NSUserDefaults standardUserDefaults]synchronize];
             recipeArr = [[(theAppDelegate).Timer_recipeIdArr reverseObjectEnumerator] allObjects];
            for (int section = 0; section < [recipeArr count]; section++)
                for (int section = 0; section < [recipeArr count]; section++)
                {

                    for (int row = 0; row < (int)[self.timerWindowTbl numberOfRowsInSection:section]; row++)
                    {

                        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:row inSection:section];

                        UITableViewCell *cell = [self.timerWindowTbl cellForRowAtIndexPath:indexPath];

                                for(UILabel *lbl in [cell.contentView subviews])
                                {
                                    if([lbl isKindOfClass:[UILabel class]])
                                    {

                                        if(lbl.tag == 1)
                                        {
                                            NSString *timer_desc= [[NSUserDefaults standardUserDefaults]objectForKey:[NSString stringWithFormat:@"timerDescString_%@",recipeArr[indexPath.row]]];
                                            NSString *recipe_title=[[NSUserDefaults standardUserDefaults] objectForKey:[NSString stringWithFormat:@"timerRecipeTitle_%@",recipeArr[indexPath.row]]];
                                            NSString *updated_timer=[[NSUserDefaults standardUserDefaults] objectForKey:[NSString stringWithFormat:@"updated_timer_%@",recipeArr[indexPath.row]]];

                                            NSString *desc=[NSString stringWithFormat:@"%@\n'%@\' %@ %@.",recipe_title,timer_desc,NSLocalizedString(@"is done in",nil),updated_timer];
                                             lbl.text=updated_timer;
                                            [lbl setNeedsDisplay];

                                            NSLog(@"*******************************lbl.text:%@",lbl.text);
                                            lbl.numberOfLines=0;
                                            [lbl sizeToFit];
                                            for(UIButton *btn in [cell.contentView subviews])
                                            {
                                                if([btn isKindOfClass:[UIButton class]])
                                                {
                                                    if(btn.tag==2)
                                                    {
                                                        btn.titleLabel.text=[NSString stringWithFormat:@"%@",recipeArr[indexPath.row]];
                                                    }
                                                }
                                            }
                                            break;

                                        }
                                    }

                                }
                         }
                }
        }
        else
        {
            secondsLeft = hours = minutes = seconds = 0;
            [self TimerInvalidate];
            NSLog(@"Time out :");
        }
    }

Answer 1

Put UI related changes in main queue for better understanding show given below code. You can also put other UI related changes in Main_queue

dispatch_async(dispatch_get_main_queue(), ^{

           lbl.text=updated_timer;

});

Answer 2

i think u need to refractor your code, u need reload the tableview cell each time when recipe timer stared for particular recipe

this is sample demo u can try with separate project, first create a Recipe class subclass of NSObject like below,

in Recipe .h file

#import <Foundation/Foundation.h>
@class Recipe;
@protocol RecipeDelegate <NSObject> //we need to notify which recipe time changing
- (void)timerChangedInRecipe:(Recipe *)recipe;
@end


@interface Recipe : NSObject
@property (nonatomic, assign) NSInteger recipeboxId;
@property (nonatomic, strong) NSString *recipeName;
@property (nonatomic, strong) NSString *countTimer;

@property (nonatomic, assign) NSTimeInterval secondsLeft;
@property (nonatomic, assign) NSTimeInterval interval;

@property (nonatomic, assign) int hours;
@property (nonatomic, assign) int minutes;
@property (nonatomic, assign) int seconds;
@property (nonatomic, strong) NSTimer *timer;
@property (nonatomic, assign) id<RecipeDelegate>delegate;

- (id)initWithRecipieId:(NSInteger)recipeId recipeName:(NSString *)name;
- (void )currentTimerString;
- (void)startTimer; //use to start the timer
- (void)stopTimer;  //stop the timer

@end

in Recipe.m file

#import "Recipe.h"

@implementation Recipe
- (id)init
{
  self = [super init];
  if(self)
  {

  }
  return self;
}

- (id)initWithRecipieId:(NSInteger)recipeId recipeName:(NSString *)name
{
   self = [super init];
   if(self)
   {
      self.recipeboxId = recipeId;
      self.recipeName =  name;
   }
   return self;
}

- (void)currentTimerString //this is similar to your method updateCounter:
{
   self.secondsLeft -- ;
   if(self.secondsLeft > 0 )
   {
     _hours = (int)self.secondsLeft / 3600;
     _minutes = ((int)self.secondsLeft % 3600) / 60;
     _seconds = ((int)self.secondsLeft %3600) % 60;
     self.countTimer = [NSString stringWithFormat:@"%02d:%02d:%02d", self.hours, self.minutes, self.seconds];
      if([self.delegate respondsToSelector:@selector(timerChangedInRecipe:)]) 
         [self.delegate timerChangedInRecipe:self]; //notifying the tableview to reload the particular cell 
  }
  else
  {
     _hours = _minutes = _seconds = 0;
     [self stopTimer]; //timer finished stop the timer
  }
}

- (void)startTimer
 {
    if(_timer == nil)
      _timer =  [NSTimer scheduledTimerWithTimeInterval:0.6f target:self selector:@selector(currentTimerString) userInfo:nil repeats:YES];
   else
       [_timer fire];
 }

 - (void)stopTimer
 {
    if(_timer)
      [self.timer invalidate];
    self.timer = nil;
 }
 @end

we are created the recipe object, this will handle the timer and notification to tableview, starting the timer and stoping the timer you can add some other functionalities if u want to.. :)

in ViewController.h file

 #import <UIKit/UIKit.h>
 #import "Recipe.h" //import the recipe class
 @interface ViewController : UIViewController <UITableViewDataSource,UITableViewDelegate,RecipeDelegate>
 @property (weak, nonatomic) IBOutlet UITableView *timerWindowTbl;
 @property (nonatomic, strong) NSMutableArray *recipeArr; //array to hold the recipes
 @end

in ViewController.m file

#import "ViewController.h"
#import "RecipeDetailViewController.h"

@interface ViewController ()

@end

@implementation ViewController

 - (void)viewDidLoad
 {
   [super viewDidLoad];
   // Do any additional setup after loading the view, typically from a nib.
   _recipeArr = [[NSMutableArray alloc] init];
   [self populateRecipe]; //i am simply creating the recipes hear for testing
 }

 - (void)viewWillAppear:(BOOL)animated
 {
   [super viewWillAppear:animated];
 }

 - (void)populateRecipe
 {
    for(NSInteger k = 0 ; k < 10 ; k++)
    {
      Recipe *recipe = [[Recipe alloc] initWithRecipieId:k recipe eName:[NSString stringWithFormat:@"recipe_%ld",(long)k]];

     [self.recipeArr addObject:recipe];
   }
}

 - (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
 }

 //just configure your tableview
 - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
 {
    return 1;
 }


 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
  {
    return self.recipeArr.count;
 }

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
 {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"RECIPEE_CELL"];
   if(cell == nil)
   {
      cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:@"RECIPEE_CELL"];
   }
   Recipe *recipe = self.recipeArr[indexPath.row];
   recipe.delegate = self;
   cell.textLabel.text = recipe.recipeName;
   cell.detailTextLabel.text = recipe.countTimer;
   return cell;
 }

 //hear go to recipe detail controller and set timer
 - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
 {
    Recipe *selRecipe = self.recipeArr[indexPath.row];
    RecipeDetailViewController *recipeDetailController = [[RecipeDetailViewController alloc] initWithNibName:@"RecipeDetailViewController" bundle:nil];
   recipeDetailController.selectedRecipe = selRecipe;
   [self.navigationController pushViewController:recipeDetailController animated:YES];
 }

 //this is the delegate method from recipe class
 //this method is responsible for reloading the particular cell 
 - (void)timerChangedInRecipe:(Recipe *)recipe
 {
   NSInteger index = recipe.recipeboxId;
   NSIndexPath *rowPath = [NSIndexPath indexPathForRow:index inSection:0];
   [self.timerWindowTbl reloadRowsAtIndexPaths:@[rowPath] withRowAnimation:UITableViewRowAnimationNone]; 
 } 
 @end

and in detail controller same as your recipe detail controller RecipeDetailViewController.h file

#import <UIKit/UIKit.h>
#import "Recipe.h"

@interface RecipeDetailViewController : UIViewController
@property (weak, nonatomic) IBOutlet UIDatePicker *timePicker;
@property (weak, nonatomic) IBOutlet UIButton *okButton;
@property (weak, nonatomic) IBOutlet UILabel *timerLabel;
@property (nonatomic, strong) Recipe *selectedRecipe;  
- (IBAction)okBtn:(id)sender;
@end

and in RecipeDetailViewController .m file,

 #import "RecipeDetailViewController.h"

 @interface RecipeDetailViewController ()

 @end

 @implementation RecipeDetailViewController

 - (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    [_timePicker addTarget:self action:@selector(timerChanged:) forControlEvents:UIControlEventValueChanged]; //i am setting a sample picker
  }

  - (void)didReceiveMemoryWarning {
   [super didReceiveMemoryWarning];
   // Dispose of any resources that can be recreated.
 }

 - (void)timerChanged:(UIDatePicker *)datePickerView
 {
    NSTimeInterval duration = datePickerView.countDownDuration;
    int hours = (int)(duration/3600.0f);
    int minutes = ((int)duration - (hours * 3600))/60;
    int seconds = minutes/60;
    _selectedRecipe.interval    = seconds + (minutes*60) + (hours*3600);
    _selectedRecipe.secondsLeft =_selectedRecipe.interval;
    _timerLabel.text = [NSString stringWithFormat:@"%02d:%02d:%02d", hours, minutes, seconds];
   _selectedRecipe.interval = duration;
 }

 - (IBAction)okBtn:(id)sender //hear start the timer particular recipe
 {
   [_selectedRecipe startTimer];
 }
 @end

Edit in the source code u are shared the problem in the cell type i think, if you want u can subclass the tableview cell and place the timer labels in the required position,

so in your code, ViewController.m file replace below method

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
 {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"RECIPEE_CELL"];
    if(cell == nil)
    {
       cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"RECIPEE_CELL"];
    }
    Recipe *recipe = self.recipeArr[indexPath.row];
    recipe.delegate = self;
    cell.textLabel.text = recipe.recipeName;
    cell.detailTextLabel.text = recipe.countTimer;
    NSLog(@"timer in cell :%@",cell.detailTextLabel.text);
    return cell;
 }

and in the RecipeDetailViewController.m file replace,

 //no need to wait for value change 
- (IBAction)okBtn:(id)sender //hear start the timer particular recipe
 {
    NSTimeInterval duration = _timePicker.countDownDuration;
   _selectedRecipe.interval = duration;
   [_selectedRecipe startTimer];
 }

and also change the timePicker mode to Count Down Timer in attribute inspector

u can download the edited code hear