@synthesize, @dynamic
·1 分钟
OC
@synthesize是给属性添加别名，并生成get、set方法（默认使用）
@interface ViewController : UIViewController
@property (assign, nonatomic) int age;
@end
@implementation ViewController
// 此时在.m文件中属性age的引用方式就是__age, 或self.age;
@synthesize age = __age;
{
NSLog(@"age is %d", __age);
}
// set
- (void)setAge:(int)age {
__age = age;
}
// get
- (int)getAge {
return __age;
}
// 不添加该语句，则系统默认生成
@synthesize age = _age;
// 提示 等同于 @synthesize age = age; 也就是该默认的 _age 为 age；
@synthesize age;
@end
@dynamic是告诉编译器不要生成getter、setter方法。
@interface ViewController : UIViewController
@property (assign, nonatomic) int height;
@end
@implementation ViewController
@dynamic height;
{
self.height = 20;
NSLog(@"height is %d", self.height);
}
@end
// 运行，直接报错
2021-06-01 14:11:01.503408+0800 Unit[3654:233676] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[ViewController setHeight:]: unrecognized selector sent to instance 0x7fd827105730'
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[ViewController height]: unrecognized selector sent to instance 0x7ff842309b40'