ios设计模式—kvo观察者模式

//
//  ViewController.m
//  strategyDemo
//
//  Created by 樊星 on 16/2/8.
//  Copyright © 2016年 樊星. All rights reserved.
//

#import "ViewController.h"
#import "strategyClass.h"

@interface ViewController ()
{
    UITextField * text ;
}
@end

@implementation ViewController
- (void)viewWillAppear:(BOOL)animated
{
    [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(postBeginMyNotification:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(postBeginMyNotification:) name:UIKeyboardWillHideNotification object:nil];
}
- (void)viewWillDisappear:(BOOL)animated
{
    [[NSNotificationCenter defaultCenter]removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter]removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}
- (void)viewDidLoad {
    [super viewDidLoad];
    text = [[UITextField alloc]initWithFrame:CGRectMake(0,[UIScreen mainScreen].bounds.size.height-50 , [UIScreen mainScreen].bounds.size.width,30 )];
    [text setBackgroundColor:[UIColor redColor]];
    [self.view addSubview:text];
}
- (void)postBeginMyNotification:(NSNotification*)notification
{
    NSValue* endrect = [notification.userInfo valueForKey:@"UIKeyboardFrameEndUserInfoKey"];
    NSNumber* animationDuaring = [notification.userInfo valueForKey:@"UIKeyboardAnimationDurationUserInfoKey"];
    //动画持续时间
    CGFloat animationDuaringValue = [animationDuaring floatValue];
    //键盘动画结束时键盘的frame
    CGRect endRext = [endrect CGRectValue];
    [UIView animateWithDuration:animationDuaringValue animations:^{
        self.view.frame = CGRectMake(0, endRext.origin.y-[UIScreen mainScreen].bounds.size.height, self.view.frame.size.width, self.view.frame.size.height);
    }];
}

@end

//核心代码如下：
- (void)viewDidLoad {
    [super viewDidLoad];
    MyAnnotation = [[BMKPointAnnotation alloc]init];
    if (!locationService) {
        locationService = [[BMKLocationService alloc]init];
        locationService.delegate = self;
    }
    [self startGetSelfLocation];
    [__APPDELEGATE addObserver:self
                   forKeyPath:@"IsShare"
                      options:NSKeyValueObservingOptionNew
                      context:nil];
    [self addMapView];
    [self addShareBtn];
}
//KVO返回检测Delegate中isShare的变化
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    shareBtn.selected = ([[change valueForKey:@"new"] isEqualToString:@"1"])? YES:NO;
}
-(void)dealloc
{
    // 移除KVO
    [__APPDELEGATE removeObserver:self forKeyPath:@"IsShare"];
}