WebView、网络操作相关及键盘相关的几个关键类

UIWebview的本地调用

• 注入js:[webview stringByEvaluatingJavaScriptFromString:]
• 本地调用，使用WebViewJavascriptBridge：- (void)registerHandler:(NSString *)handlerName handler:(WVJBHandler)handler

WKWebView的本地调用

• 注入js:[wkwebview evaluateJavaScript:]
• 首先通过WKUserContentController -> addScriptMessageHandler: 以及 addUserScript: ,实现WKScriptMessageHandler响应脚本消息:- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message 和 js的注入；
• WKNavigationDelegate：跟踪网页加载进度，以及决定采取什么的处理策略；
• WKUIDelegate:根据网页的行为展示本地的UI视图；

自定义NSURLProtocol

• NSURLProtocol能够让你去重新定义苹果的URL加载系统 (URL Loading System)的行为，URL Loading System里有许多类用于处理URL请求，比如NSURL，NSURLRequest，NSURLConnection和NSURLSession等，当URL Loading System使用NSURLRequest去获取资源的时候，它会创建一个NSURLProtocol子类的实例，你不应该直接实例化一个NSURLProtocol，NSURLProtocol看起来像是一个协议，但其实这是一个类，而且必须使用该类的子类，并且需要被注册。
• 不管你是通过UIWebView, NSURLConnection 或者第三方库 (AFNetworking, MKNetworkKit等)，他们都是基于NSURLConnection或者 NSURLSession实现的，因此你可以通过NSURLProtocol做自定义的操作。
  • 重定向网络请求
  • 忽略网络请求，使用本地缓存
  • 自定义网络请求的返回结果
  • 一些全局的网络请求设置

• 子类化NSURLProtocol并注册

   //子类化
   @interface CustomURLProtocol : NSURLProtocol
   @end
     
   //注册
   - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
       //注册protocol
       [NSURLProtocol registerClass:[CustomURLProtocol class]];
       return YES;
   }
  

• 实现Custom URLProtocol

  • +canInitWithRequest:这个方法主要是说明你是否打算处理对应的request，如果不打算处理，返回NO，URL Loading System会使用系统默认的行为去处理；如果打算处理，返回YES，然后你就需要处理该请求的所有东西，包括获取请求数据并返回给 URL Loading System。

      + (BOOL)canInitWithRequest:(NSURLRequest *)request
      {
        //只处理http和https请求
          NSString *scheme = [[request URL] scheme];
          if ( ([scheme caseInsensitiveCompare:@"http"] == NSOrderedSame ||
           [scheme caseInsensitiveCompare:@"https"] == NSOrderedSame))
          {
              //看看是否已经处理过了，防止无限循环
              if ([NSURLProtocol propertyForKey:URLProtocolHandledKey inRequest:request]) {
                  return NO;
              }
           
              return YES;
          }
          return NO;
      }
    

• +canonicalRequestForRequest:通常该方法你可以简单的直接返回request，但也可以在这里修改request，比如添加header，修改host等，并返回一个新的request，这是一个抽象方法，子类必须实现。

   + (NSURLRequest *) canonicalRequestForRequest:(NSURLRequest *)request {
       NSMutableURLRequest *mutableReqeust = [request mutableCopy];
       mutableReqeust = [self redirectHostInRequset:mutableReqeust];
       return mutableReqeust;
   }
     
   +(NSMutableURLRequest*)redirectHostInRequset:(NSMutableURLRequest*)request{
       if ([request.URL host].length == 0) {
           return request;
       }
     
       NSString *originUrlString = [request.URL absoluteString];
       NSString *originHostString = [request.URL host];
       NSRange hostRange = [originUrlString rangeOfString:originHostString];
       if (hostRange.location == NSNotFound) {
           return request;
       }
       //定向到bing搜索主页
       NSString *ip = @"cn.bing.com";
     
       // 替换域名
       NSString *urlString = [originUrlString stringByReplacingCharactersInRange:hostRange withString:ip];
       NSURL *url = [NSURL URLWithString:urlString];
       request.URL = url;
     
       return request;
   }
  

• +requestIsCacheEquivalent:toRequest:主要判断两个request是否相同，如果相同的话可以使用缓存数据，通常只需要调用父类的实现。

   + (BOOL)requestIsCacheEquivalent:(NSURLRequest *)a toRequest:(NSURLRequest *)b{
       return [super requestIsCacheEquivalent:a toRequest:b];
   }
  

• -startLoading -stopLoading : 这两个方法主要是开始和取消相应的request，而且需要标示那些已经处理过的request。

   - (void)startLoading {
       NSMutableURLRequest *mutableReqeust = [[self request] mutableCopy];
       //标示改request已经处理过了，防止无限循环
       [NSURLProtocol setProperty:@YES forKey:URLProtocolHandledKey inRequest:mutableReqeust];
       self.connection = [NSURLConnection connectionWithRequest:mutableReqeust delegate:self];
   }
     
   - (void)stopLoading {
       [self.connection cancel];
   }
  

• NSURLConnectionDataDelegate方法,在处理网络请求的时候会调用到该代理方法，我们需要将收到的消息通过client返回给URL Loading System。

   - (void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
       [self.client URLProtocol:self didReceiveResponse:response cacheStoragePolicy:NSURLCacheStorageNotAllowed];
   }
     
   - (void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
       [self.client URLProtocol:self didLoadData:data];
   }
     
   - (void) connectionDidFinishLoading:(NSURLConnection *)connection {
       [self.client URLProtocolDidFinishLoading:self];
   }
     
   - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
       [self.client URLProtocol:self didFailWithError:error];
   }
  

自定义键盘 UITextInputDelegate 方法定义

- (void)selectionWillChange:(nullable id <UITextInput>)textInput;
- (void)selectionDidChange:(nullable id <UITextInput>)textInput;
- (void)textWillChange:(nullable id <UITextInput>)textInput;
- (void)textDidChange:(nullable id <UITextInput>)textInput;

自定义键盘UIInputViewController的textDocumentProxy定义

@protocol UITextDocumentProxy <UIKeyInput>
    
@property (nullable, nonatomic, readonly) NSString *documentContextBeforeInput;
@property (nullable, nonatomic, readonly) NSString *documentContextAfterInput;
    
// An app can store UITextInputMode in its document context, when user switches to the document, the host will pass the inputMode as documentInputMode to the UIInputViewController,
// which can switch to the inputMode and set primaryLanguage if it supports it.
@property (nullable, nonatomic, readonly) UITextInputMode *documentInputMode NS_AVAILABLE_IOS(10_0);
    
- (void)adjustTextPositionByCharacterOffset:(NSInteger)offset;
    
@end
    
//-----------------
    
@protocol UIKeyInput <UITextInputTraits>
    
#if UIKIT_DEFINE_AS_PROPERTIES
@property(nonatomic, readonly) BOOL hasText;
#else
- (BOOL)hasText;
#endif
- (void)insertText:(NSString *)text;
- (void)deleteBackward;
    
@end
    

参考以上：

iOS开发之— NSURLProtocol