Not able to access NSMutableArray from another class - ios

Question

I've read through many posts here but I can't seem to make my array available in another class.
I want to access the array plusTransactions in CPPHistoryViewController (a table controller, in a container as a child of CPPSecondViewController) from class CPPSecondViewController.
CPPSecondViewController.h
#import <UIKit/UIKit.h>
#interface CPPSecondViewController : UIViewController <UIWebViewDelegate>
#property (weak, nonatomic) IBOutlet UIWebView *webView;
#property (weak, nonatomic) IBOutlet UISegmentedControl *segmentedController;
#property (weak, nonatomic) NSMutableArray *plustransactions;
#property (weak, nonatomic) NSMutableArray *campustransactions;
#property (weak, nonatomic) NSMutableArray *mealtransactions;
#end
CPPSecondViewController.m
#import "CPPSecondViewController.h"
#interface CPPSecondViewController ()
#implementation CPPSecondViewController
#end
#synthesize plustransactions = _plustransactions;
#synthesize campustransactions = _campustransactions;
#synthesize mealtransactions = _mealtransactions;
...
_plustransactions = newPlustransactions;
NSLog(#"%#", newPlustransactions);
NSLog(#"%#%lu", #"That's how many: ", (unsigned long)_plustransactions.count);
CPPHistoryViewController *historyView = [[CPPHistoryViewController alloc]init];
[historyView.tableView reloadData];
This is good, returns all of my array items and count is 7.
CPPHistoryViewController.h
#import <UIKit/UIKit.h>
#interface CPPHistoryViewController : UITableViewController <UITableViewDelegate, UITableViewDataSource>
#end
CPPHistoryViewController.m
#import "CPPHistoryViewController.h"
#import "CPPSecondViewController.h"
#import "CPPPlusTransaction.h"
#import "CPPCampusTransaction.h"
#import "CPPMealTransaction.h"
#import "CPPHistoryCell.h"
#interface CPPHistoryViewController ()
#end
#implementation CPPHistoryViewController
...
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
CPPSecondViewController *secondView = [[CPPSecondViewController alloc] init];
NSMutableArray *plusTransactions = [[NSMutableArray alloc]init];
plusTransactions = secondView.plustransactions;
NSMutableArray *campusTransactions = [[NSMutableArray alloc]init];
campusTransactions = secondView.campustransactions;
NSMutableArray *mealTransactions = [[NSMutableArray alloc]init];
mealTransactions = secondView.mealtransactions;
NSLog(#"Table formatting called");
NSLog(#"%ld", (long)secondView.segmentedController.selectedSegmentIndex);
switch (secondView.segmentedController.selectedSegmentIndex) {
case 0:
NSLog(#"%#%lu", #"PlusTransactions", (unsigned long)plusTransactions.count);
return plusTransactions.count;
break;
case 1:
NSLog(#"%#%lu", #"CampusTransactions", (unsigned long)campusTransactions.count);
return campusTransactions.count;
break;
case 2:
NSLog(#"%#%lu", #"MealTransactions", (unsigned long)mealTransactions.count);
return mealTransactions.count;
break;
}
return 1;
}
...
#end
Here's where things get weird. Any array I call from here returns with a count of 0. Any ideas?

Answer 1

I assume what you want is to get the array data stored in CPPSecondViewController to be availalbe in CPPHistoryViewController. But as per the code you posted,
CPPHistoryViewController *historyView = [[CPPHistoryViewController alloc]init];
[historyView.tableView reloadData];
This just create new instance and the tableView inside the view is reloaded. But in cellForRowAtIndexPath, you are creating new instance of CPPSecondViewController, thats wrong.
What you can do is, simply pass the CPPSecondViewController instance before reloading tableView.
In CPPHistoryViewController.h, create a property for keeping secondView like this
#property (strong, nonatomic) CPPSecondViewController *secondView;
then, change your code in CPPSecondViewController like below:
CPPHistoryViewController *historyView = [[CPPHistoryViewController alloc]init];
historyView.secondView = self;
[historyView.tableView reloadData];
Also, remove alloc init statements from cellForRowAtIndexPath, just use secondView.plustransactions here.
Hope this helps!

Answer 2

CPPSecondViewController *secondView = [[CPPSecondViewController alloc] init];
Here you are creating a new object, So all values are nill.
Here you can only set values in to second view controller.
in your History class, you nedd to create a property of a second class they you can set value in to Second class
#property (nonatomic, retain) Secondclass* secondclass;
[secondClass setAry: ary];

Answer 3

CPPSecondViewController *secondView = [[CPPSecondViewController alloc] init];
in this code, the view controller is just init, the properties is all nil, it's a new view controller instance.
setup properties in init method, or access the second view's view property, to load view, to trigger the property initialize.
if you want reference the second view controller from history view controller, you can add a property in history view controller refer to second view controller.
in CPPHistoryViewController.h
#property (weak, nonatomic) CPPSecondViewController *secondViewController;
and set this property in your show code.
in CPPSecondViewController.m
_plustransactions = newPlustransactions;
NSLog(#"%#", newPlustransactions);
NSLog(#"%#%lu", #"That's how many: ", (unsigned long)_plustransactions.count);
CPPHistoryViewController *historyView = [[CPPHistoryViewController alloc]init];
historyView.secondViewController = self;
[historyView.tableView reloadData];