attempt to insert nil object from objects[0] in objective-c - ios

Question

I am trying to create a dynamic top menu.
I have to get some data from a json request and display this data in one of the sections of the top menu. I'm new in Objective-C. I also tried with NSMutableArrays and I had an error. Only one MutableArray and I can show the top menu. I am following this third party framework for top menu “https://github.com/dopcn/DOPNavbarMenu”.
- (DOPNavbarMenu *)menu {
if (_menu == nil) {
[strArray objectAtIndex:0];
NSLog(#"Random Selection is:%#",strArray);
_menu = [[DOPNavbarMenu alloc] initWithItems:#[strArray] width:self.view.dop_width maximumNumberInRow:_numberOfItemsInRow];
_menu.backgroundColor = [UIColor blackColor];
_menu.separatarColor = [UIColor whiteColor];
_menu.delegate = self;
}
return _menu;
}
-(void)loadData
{
strResponse=[dictionary objectForKey:#"data"];
strMsg=[strResponse valueForKey:#"Text"];
NSLog(#“string message is :%#",strMsg);
NSLog(#"String Response is :%#",strResponse);
NSLog(#"Text Response is: %#",strMsg);
strArray = [[NSMutableArray alloc] init];
[strArray addObject:strMsg];
NSLog(#"Array values are - %#", strArray);
}
Array values are: Life Style,Care Plans,Trackers/Diaries,Questionnaires/Assessments.
but i got exception like this:
* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[__NSPlaceholderArray initWithObjects:count:]: attempt to insert nil object from objects[0]'

Answer 1

Ok, per your comment
but i want to call menu method before loadData finishes
the issue lies here :
_menu = [[DOPNavbarMenu alloc] initWithItems:#[strArray] width:self.view.dop_width maximumNumberInRow:_numberOfItemsInRow];
Before loadData is run, I assume that strArray is nil. This causes this part #[strArray] to fail - this creates a new array with strArray as its only element, which cannot be nil.
I also assume that you wanted to rather pass strArray itself there, not wrap it in another array.
Now, if you call menu before populating strArray in loadData, there will likely be no items present in the menu, unless you have a way to update it with new items after loadData finishes.
To summarise : to fix your immediate issue, you should change the above line to this :
_menu = [[DOPNavbarMenu alloc] initWithItems:strArray width:self.view.dop_width maximumNumberInRow:_numberOfItemsInRow];
which should work, but there won't be any items present in the menu, because of reasons explained above.