How to return a NSMutableArray from a method

Question

I have a method in a NSObject Class that I am executing from another ViewController Class, I would like to reutrn a NSMutableArray however I am not sure how to pass that into a variable in the ViewController class.

Updated Code:

NSObject Class is called Axis

Axis.h // declare my method here with return type of NSMutableArray

- (NSMutableArray *)assignAxes:(NSArray*)axesData;

Axis.m

- (NSMutableArray *)assignAxes:(NSArray*)axesData {
//..

//pass some NSDictionaries into a MutableArray called myMutableArray

return myMutableArray;
}

Now I have a View Controller called FinalViewViewController and I want to call assignAxes method from this viewController, and I would like to put the returning myMutableArray into a mutableArray variable in FinalViewViewController but am not sure how... I only know how to call the method not pass the returning value into a variable to be used.

FinalViewViewController.m

Axis *axis = [[Axis alloc] init];
    NSMutableArray *tempGetSeriesObjArray = [[NSMutableArray alloc] init]; // create holder variable for returning mutableArray
    tempGetSeriesObjArray = [axis assignAxes:series]; // gives an error

This is the error I am getting from that last line of code

Incompatible pointer types assigning to 'NSMutableArray *__strong' from 'Axis *'

any help would be appreciated.

**Incompatible pointer types assigning to 'NSMutableArray *__strong' from 'NSObjectClass *' ** — HurkNburkS
– HurkNburkS, Commented Apr 8, 2013 at 3:25
Maybe if you want to pass an NSMutableArray you should pass an NSMutableArray. — Hot Licks
– Hot Licks, Commented Apr 8, 2013 at 3:26
Note that you don't pass anything into a class, you pass stuff to an instance of a class. And the two most popular ways to do that are to make the thing being passed a parameter on init, or pass the value via a property. — Hot Licks
– Hot Licks, Commented Apr 8, 2013 at 3:29
Note that you should never name one of your classes "NS...". That prefix is reserved for Apple. Also avoid "UI", "CF", et al. — Hot Licks
– Hot Licks, Commented Apr 8, 2013 at 19:55

Christian 'fuzi' Orgler · Accepted Answer · 2013-04-08 03:55:22Z

1

In your NSObject Class, first go in your .h file and make the declaration of the array and set the property

@interface YourNSObjectClass : NSObject {
    NSMutableArray *_myArray;
}

@property (nonatomic, retain) NSMutableArray *_myArray;

- (NSMutableArray *) getMyArray; // declare method

@end

So now, you have to sync your variable and initialize it in the initMethod - if you have a custom init-method you have to declare it too and make it inside of there.

@synthesize _myArray;

- (id) init {
     if(self = [super init]) {
           _myArray = [[NSMutableArray alloc] init];
     }
     return self;
}

And the getter-method should work too

- (NSMutableArray *) getMyArray {
    return _myArray;
}

edited Apr 8, 2013 at 3:55

answered Apr 8, 2013 at 3:26

Christian 'fuzi' Orgler

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5 Comments

HurkNburkS Over a year ago

yup this is what I have done this bit I am not too sure on what to do is how to pass that returning MutableArray into a MutableArray in the Viewcontroller I call it from.. I hope that makes sense.

Christian 'fuzi' Orgler Over a year ago

a little bit more clean code would be great.. what's this NSObjectClass?

Christian 'fuzi' Orgler Over a year ago

@HurkNburkS did you implemented your variable like in my answer?

HurkNburkS Over a year ago

Sorry just been updating the question. It shows you I have implemented everything.

Christian 'fuzi' Orgler Over a year ago

@HurkNburkS you can upload your .h & .m file to some file server & I will try it in my xcode by myself to solve it..

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