通知做的真夜间模式

 //注册通知

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

    

    //判断模式

    NSString *str = [[NSUserDefaults standardUserDefaults]objectForKey:@"night"];

    if ([str isEqualToString:@"yes"]) {

        self.view.backgroundColor = [UIColor lightGrayColor];

        self.navigationController.navigationBar.barTintColor = [UIColor blackColor];

    }

    

    

    

}

//接受通知触发的方法

-(void)changeColor:(NSNotification *)notification

{

    

    NSString *str = [[NSUserDefaults standardUserDefaults]objectForKey:@"night"];

    if ([str isEqualToString:@"yes"]) {

        self.view.backgroundColor = [UIColor lightGrayColor];

        self.navigationController.navigationBar.barTintColor = [UIColor blackColor];

    }else

    {

        self.view.backgroundColor = [UIColor redColor];

        self.navigationController.navigationBar.barTintColor = [UIColor greenColor];

    }

    

}