Objective-C 属性 成员变量

属性声明

@property (nonatomic, copy) NSString *name;

系统帮我们做了三件事:

-(void)setName:(NSString *)name;
-(NSString *)name;
_name;

setter，getter ，成员变量

属性 = setter + getter + 成员变量; (ps: setter/getter的调用只能通过点语法)

//getter 成员变量
@property (nonatomic, copy , readonly) NSString *name;

// setter getter 成员变量 readwrite是默认
@property (nonatomic, copy , readwrite) NSString *name;

//setter/getter 重命名
@property (nonatomic, copy , getter=getterName, setter=setterName:) NSString *name;

如果我们自己重写了setter和getter,系统就不会为我们创建成员变量：

-(void)test{
    //Use of undeclared identifier '_name'
    _name = @"";
}

-(void)setName:(NSString *)name{
    
}

-(NSString *)name{
    return @"";
}

就不能直接使用成员变量。解决方案通过下面方法:

@synthesize

@synthesize name = _name; 属性名 = 成员变量名

-(void)test{
    _name = @"";
}

-(void)setName:(NSString *)name{
    _name = name;
}

-(NSString *)name{
    return @"";
}

@synthesize是如果没有自定义setter和getter，编译器会帮你生成成员变量；

@dynamic 是告诉编译器我自己实现setter和getter ，不用帮我加setter和getter, 如果没有自己实现setter和getter则不能使用点语法访问该属性。

@dynamic 修饰属性编译器不生成setter，getter和成员变量。

@interface CPerson ()

@property (nonatomic, copy) NSString *name;

@end


@implementation CPerson

@dynamic name;


@end


    Class personClass = NSClassFromString(@"CPerson");
    unsigned int ivarCount = 0;
    Ivar *ivarList = class_copyIvarList(personClass, &ivarCount);
    for (int i = 0; i < ivarCount; i++) {
        NSString *ivarName = [NSString stringWithUTF8String:ivar_getName(ivarList[i])];
        NSLog(@"ivarName : %@", ivarName);
    }

    unsigned int methodCount = 0;
    Method *methodList = class_copyMethodList(personClass, &methodCount);
    for (int i = 0; i < methodCount; i++) {
        NSString *methodName = NSStringFromSelector(method_getName(methodList[i]));
        NSLog(@"methodName : %@", methodName);
    }