KVC && KVO 初見，kvckvo

KVC && KVO 初見，kvckvo

#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

很普通很簡單。。。

下面在ViewControler中調用該類，完成對這個人的年齡的增加

#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];//添加對keith keyPath的監視    }}-(void)dealloc{    [keith removeObserver:self forKeyPath:@"age"];//不用的時候移除註冊}@end

可以看出如果通過這樣的模式有個好處是能減少模型和視圖的耦合關鍵，模型只管運算，視圖的變化通過KVO監視索引值的變化，自動更新。