//前一个界面

//注册通知

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(notification:) name:@"notification" object:nil];

    // Do any additional setup after loading the view.

}

//执行通知方法

- (void) notification:(NSNotification *)notifi{

    NSLog(@"++++++");

    NSLog(@"%@",notifi.userInfo);

}

//移除通知

-(void) dealloc{

    //第一种 移除该控制器所有的通知

    [[NSNotificationCenter defaultCenter] removeObserver:self];

    //第二种 移除该控制器下名为"notification"的通知

  //  [[NSNotificationCenter defaultCenter] removeObserver:self name:@"notification" object:nil];

}

//后一个界面

 //创建传值信息

    NSDictionary *dict=[[NSDictionary alloc]initWithObjectsAndKeys:@"val1",@"key1",@"val2",@"key2", nil];

    //创建通知

    NSNotification *notification=[NSNotification notificationWithName:@"notification" object:nil userInfo:dict];

    //通过通知中心发送通知

    [[NSNotificationCenter defaultCenter] postNotification:notification];
    

//后一个界面

.h文件

@interface jViewController : UIViewController

//定义block

@property (nonatomic,copy) void (^NextViewControllerBlock)(NSString *tfText);

@end

.m文件

-(void) btnClick:(UIButton *)btn{

    //判断block是否为空

    if (self.NextViewControllerBlock) {

        self.NextViewControllerBlock(@"我是后一个界面传的值");

    }

    [self.navigationController popViewControllerAnimated:YES];

}

//前一个界面

//.m文件

-(void) btnClick:(UIButton *)btn{

    jViewController *nextVC = [[jViewController alloc]init];

    nextVC.NextViewControllerBlock = ^(NSString *tfText){

        NSLog(@"++++%@",tfText);

    };

    [self.navigationController pushViewController:nextVC animated:YES];

}

//后一个界面

//首先在.h定义获值属性（就是要有接收传值过来的属性）

@interface jViewController : UIViewController

@property( copy,nonatomic)NSString *str;

@end

//.m

-(void) btnClick:(UIButton *)btn{

    NSLog(@"++++%@",_str);

}

//前一个界面

-(void) btnClick:(UIButton *)btn{

    //跳转到后一个界面，也把值传过去

    jViewController *nextVC = [[jViewController alloc]init];

    nextVC.str=@"我是第一个界面传给第二个界面的值";

    [self.navigationController pushViewController:nextVC animated:YES];

}

 NSUserDefaults *userDefaults=[NSUserDefaults standardUserDefaults];

    //存储数据

    [userDefaults setObject:<#(nullable id)#> forKey:<#(nonnull NSString *)#>];

    [userDefaults setInteger:<#(NSInteger)#> forKey:<#(nonnull NSString *)#>];

    [userDefaults setBool:<#(BOOL)#> forKey:<#(nonnull NSString *)#>];

    [userDefaults setURL:<#(nullable NSURL *)#> forKey:<#(nonnull NSString *)#>];

    [userDefaults setFloat:<#(float)#> forKey:<#(nonnull NSString *)#>];

    [userDefaults setDouble:<#(double)#> forKey:<#(nonnull NSString *)#>];

    [userDefaults setValue:<#(nullable id)#> forKey:<#(nonnull NSString *)#>];

    //读取数据

    [userDefaults objectForKey:<#(nonnull NSString *)#>];

    [userDefaults integerForKey:<#(nonnull NSString *)#>];

    [userDefaults boolForKey:<#(nonnull NSString *)#>];

    [userDefaults URLForKey:<#(nonnull NSString *)#>];

    [userDefaults floatForKey:<#(nonnull NSString *)#>];

    [userDefaults doubleForKey:<#(nonnull NSString *)#>];

    [userDefaults valueForKey:<#(nonnull NSString *)#>];