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I do a custom Class ,but I can not Declaring Custom Attributes for Properties to set value into the Class

Custom Class dog.h Only had a property named" kind" @interface dog : NSObject

@property(nonatomic,strong)NSString* kind;


//Declare Custom Attributes named "dg"

import "dog.h"

@interface HungAppDelegate : UIResponder <UIApplicationDelegate>

@property(strong,nonatomic) dog * dg; @end

@implementation HungAppDelegate

  • (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    self.dg.kind = @"abc"; // is this line Right ???????????

    NSLog(@"---%@----",self.dg.kind); return YES; }


result is : -------NULL------

I hope it will show abc , but do not , how can I solve it ??

1 Answer

You need to alloc init your Class before you can start using it.

self.dg = [dog alloc]init];

self.dg.kind = @"abc"; 

NSLog(@"---%@----",self.dg.kind); return YES;  // this will print abc