KVC&&KVO初见

2019-11-14 19:49:48

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Look，这是一个很简单的要求，点击Add me，age +1.

想一想的话很简单的，设置一个属性Nsinteger age，点击button add me，直接加1在重新显示Lable就好啦，不过，我们今天是来练习KVC和KVO的，苹果的键值编程哈哈

首先我们定义一个Human的类，并且完成了它的初始化方法

#import <Foundation/Foundation.h>@interface human : NSObject@PRoperty (nonatomic,assign) NSString *name;@property (nonatomic,assign) NSInteger age;-(id)initHuman:(NSString *)Initname hisage:(NSInteger) Initage;@end

#import "human.h"@implementation human-(id)initHuman:(NSString *)Initname hisage:(NSInteger)Initage{    if(self=[super init]){        _name=Initname;        _age=Initage;           }    return self;}@end

很普通很简单。。。

下面在ViewControler中调用该类，完成对这个人的年龄的增加

#import <UIKit/UIKit.h>#import "human.h"@interface ViewController : UIViewController<UIWebViewDelegate>{    human *keith;}@property (weak, nonatomic) IBOutlet UILabel *Infoshow;- (IBAction)Addme:(id)sender;@end

#import "ViewController.h"@interface ViewController ()@end@implementation ViewController-(void)viewWillAppear:(BOOL)animated{    [super viewWillAppear:animated];       keith=[[human alloc]initHuman:@"keith" hisage:26];    self.Infoshow.text=[NSString stringWithFormat:@"name is %@,age is %ld",keith.name,keith.age];    [keith addObserver:self forKeyPath:@"age" options:NSKeyValueObservingOptionOld|NSKeyValueObservingOptionNew context:nil];//}- (IBAction)Addme:(id)sender {    keith.age+=1;      }-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context{    if ([keyPath isEqualToString:@"age"] && object==keith) {          self.Infoshow.text=[NSString stringWithFormat:@"name is %@,age is %ld",keith.name,keith.age];//添加对keith keyPath的监视    }}-(void)dealloc{    [keith removeObserver:self forKeyPath:@"age"];//不用的时候移除注册}@end