iOS 成员变量和属性的关系

#import <UIKit/UIKit.h>

//Public: is available an accessible from anywhere

//Protected: is available only to subclasses

//Private: is available to the class only

//Package: is available from that package only aka Framework or Library

@interface ViewController :
UIViewController {

    

    //成员变量

    

   
//如果一个变量是public，我觉得不需要写在这里，直接写成property就可以，因为写成property，会自动生成一个
_ + 属性名的成员变量

    // 例如，如果有一个属性是 propertyName，则会生成成员变量_propertyName，如果此处有_propertyName，则不生成

//    @public

//        NSString *_publicString;

    

    @protected

        NSString *protectedString;

    

//    @private

//        NSString* privateString;

    

//    @package

//        BOOL packageVar;

}

//属性变量

@property(nonatomic,
copy) NSString *propertyString;

@property(nonatomic,
copy) NSString *publicString;

@property(nonatomic,
copy) NSString *foo;

@end

#import "ViewController.h"

@interface
ViewController ()

//如果自己内部需要setter和getter来实现一些东西，就在.m文件的类目里用property来声明

//写在这里的property不会生成成员变量

@property(nonatomic,
strong) UIButton *loginButton;

@end

@implementation ViewController {

   
//私有变量一般写在这里

    @private

        NSString* privateString;

}

@synthesize foo;

//@dynamic foo;

- (void)viewDidLoad {

    [super
viewDidLoad];

    // Do any additional setup after loading the view, typically from a nib.

    

//    privateString = @"私有变量";

//    

//    NSLog(@"%@", privateString);   

}

- (void)setLoginButton:(UIButton *)loginButton {

    self.loginButton = loginButton;

}

- (UIButton *)loginButton {

    return
self.loginButton;

}

- (void)didReceiveMemoryWarning {

    [super
didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

@end

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

    // Override point for customization after application launch.

    

    ViewController *newViewController = [[ViewController
alloc] init];

    

    newViewController.propertyString =
@"这是属性字符串";

    

    unsigned
int count = 0;
//count记录变量的数量

    

   
// 获取类的所有成员变量

    Ivar *members =
class_copyIvarList([ViewController
class], &count);

    for (int i =
0; i < count; i++) {

        Ivar ivar = members[i];

       
// 取得变量名并转成字符串类型

        const
char *memberName =
ivar_getName(ivar);

        NSLog(@"变量名 = %s",memberName);

    }

   
// 获取类的所有成员属性

    objc_property_t *properties =class_copyPropertyList([ViewController
class], &count);

    for (int i =
0; i<count; i++)

    {

        objc_property_t property = properties[i];

        const
char* char_f =property_getName(property);

        NSString *propertyName = [NSString
stringWithUTF8String:char_f];

        NSLog(@"属性名 = %@",propertyName);

    }

    

    return
YES;

}