自学知识(三)

1.设置状态栏的样式:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
     [UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleLightContent;
    return YES;
}

2.数组的遍历：

- (NSEnumerator *)objectEnumerator;从前向后

- (NSEnumerator *)reverseObjectEnumerator;从后向前

        NSArray* reversedArray = [[_myArray reverseObjectEnumerator] allObjects];

3. 设置导航栏的标题样式：

 NSDictionary *dic = @{NSFontAttributeName:[UIFont systemFontOfSize:40],NSForegroundColorAttributeName:[UIColor redColor]};
    
//    self.navigationBar.titleTextAttributes = [NSDictionary dictionaryWithObject:[UIColor blackColor] forKey:NSForegroundColorAttributeName];
    self.navigationBar.titleTextAttributes = dic;
    

4.复写pushViewController方法，隐藏标签栏：

#pragma mark 隐藏tabbar
-(void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    
    if (self.viewControllers.count > 0) {
        viewController.hidesBottomBarWhenPushed = YES;
    }
    [super pushViewController:viewController animated:YES];
}

5.

IOS7之后   self.edgesForExtendedLayout=UIRectEdgeNone;

self.automaticallyAdjustsScrollViewInsets=NO;

只要设置了 self.edgesForExtendedLayout ，UIRectEdgeAll的时候会让tableView从导航栏下移44px，设置为UIRectEdgeNone的时候，刚刚在导航栏下面。

self.edgesForExtendedLayout=UIRectEdgeNone or UIRectEdgeAll;
self.automaticallyAdjustsScrollViewInsets=YES;

有的时候只要automaticallyAdjustsScrollViewInsets设置了YES，不管其他任何值tableView都会在导航栏下面， 
手动改self.tableView.contentInset=UIEdgeInsetsMake(64, 0, 0, 0);也不影响tableView在导航栏下面。

6.设置选中TabBarItem的样式和正常状态样式:

[[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIColor grayColor], NSForegroundColorAttributeName, nil] forState:UIControlStateNormal];
    
[[UITabBarItem appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIColor blackColor], NSForegroundColorAttributeName, nil] forState:UIControlStateSelected];
    

7.不设置渲染,会是系统默认的蓝色效果:

if (iOS7) {
        childController.tabBarItem.image = [normal imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
        childController.tabBarItem.selectedImage = [selected imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    }else{
        childController.tabBarItem.selectedImage = selected;
    }
    

设置UIImage的渲染模式：UIImage.renderingMode

着色（Tint Color）是iOS7界面中的一个.设置UIImage的渲染模式：UIImage.renderingMode重大改变，你可以设置一个UIImage在渲染时是否使用当前视图的Tint Color。UIImage新增了一个只读属性：renderingMode，对应的还有一个新增方法：imageWithRenderingMode:，它使用UIImageRenderingMode枚举值来设置图片的renderingMode属性。该枚举中包含下列值：

1. UIImageRenderingModeAutomatic  // 根据图片的使用环境和所处的绘图上下文自动调整渲染模式。  
2. UIImageRenderingModeAlwaysOriginal   // 始终绘制图片原始状态，不使用Tint Color。  
3. UIImageRenderingModeAlwaysTemplate   // 始终根据Tint Color绘制图片，忽略图片的颜色信息。  

8.

//不设置此处会导致View上移

    if(iOS7) {

        self.edgesForExtendedLayout = UIRectEdgeNone;

        self.extendedLayoutIncludesOpaqueBars = NO;

        self.modalPresentationCapturesStatusBarAppearance = NO;

    }

 

9.网络请求注意点:

+ (void)getWithURL:(NSString *)url params:(NSDictionary *)params success:(HttpSuccess)success failure:(HttpFailure)failure{
    //1.使用 NSURLConnection版本的AFNetworking
    //1.1创建一个AFN管理对象
    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
    //1.2告诉manager只下载原始数据, 不要解析数据(一定要写)
    //AFN即可以下载网络数据, 又可以解析json数据,如果不写下面的  自动就解析json
    //由于做服务器的人返回json数据往往不规范, 凡是AFN又检查很严格,导致json解析往往失败
    //下面这句话的意思是 告诉AFN千万别解析, 只需要给我裸数据就可以
    manager.responseSerializer = [AFHTTPResponseSerializer serializer];
    [manager GET:url parameters:params success:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSData *data = operation.responseData;
        NSDictionary *dict = [NSJSONSerialization  JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];
        if (success) {
            success(dict);
        }
    }failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        if (failure) {
            failure(error);
        }
    }];
}