如何从视图控制器访问NSObject类/实例变量？

Question

I want to pass a NSString value to a class method of a NSObject class: +(void)loadTableData:(myCompletion) compblock; . So I can only use a class variable NSString *categoryID for use in the class method. I declare it in the .h file trying to let it also be used for public access. But I tried many ways, and can only declare it like below. Other positions will give me warning.

#import <Foundation/Foundation.h>

typedef void(^myCompletion)(NSArray *);
NSString *categoryID;

@interface ThirdVCLoadTable : NSObject
+ (void)loadTableData:(myCompletion) compblock;
@end

Then the problem is I am still not able to access it in my view controller class . The error message is always: Property "categoryID" not found on object of type "ThirdVCLoadTable" , no matter what I try in order to access the NSString *categoryID .

For example,

ThirdVCLoadTable *load = [[ThirdVCLoadTable alloc] init];
load.categoryID = [NSString stringWithFormat:@"%li", (long)indexPath.row + 1];

Answer 1

It's not a property of the class. Try putting

@property (copy, nonatomic) NSString * categoryID;

below @interface

Answer 2

Declare a property in that class which you will call later from another view.

Suppose, in viewcontrollerA , in .h

@property (copy, nonatomic) NSString * StrName;

In viewcontrollerB, implement it like :

viewcontrollerA *vc = [[viewcontrollerA alloc]    initWithNib:@"viewcontrollerA" bundle:nil];
vc.StrName = @"XYZ";
[self pushViewController:vc animated:YES];

Get more help from this :

How to use NSString from NSObject class in multiple Classes (View Controllers)

Passing Data between View Controllers

Answer 3

Step 1: suppose my ClassName is Info.

Info.h file

@interface Info : NSObject
typedef void(^myCompletion)(NSArray *);

@end
@interface ThirdVCLoadTable : NSObject

@property (strong, nonatomic) NSString * categoryID;

+ (void)loadTableData:(myCompletion) compblock;

Info.m file

+ (void)loadTableData:(myCompletion) compblock {

}

if you want to access Class Method in viewControllers than you can use like

ThirdVCLoadTable* load = [[ThirdVCLoadTable alloc] init];
load.categoryID = [NSString stringWithFormat:@"%li", (long)indexPath.row + 1];