JavaScript与OC交互

[[[UIWebView alloc] init] stringByEvaluatingJavaScriptFromString:@"alert(100);"];//oc直接运行js代码

• html代码

Call

• OC代码

  -(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
  {
    // url == JavaScript://sendMessage_?200
    NSString *url = request.URL.absoluteString;
    NSString *scheme = @"JavaScript://";
    if ([url hasPrefix:scheme]) {
        // 获得协议后面的路径  path == sendMessage_number2_?200&300
        NSString *path = [url substringFromIndex:scheme.length];
        // 利用?切割路径
        NSArray *subpaths = [path componentsSeparatedByString:@"?"];
        // 方法名 methodName == sendMessage:number2:
        NSString *methodName = [[subpaths firstObject] stringByReplacingOccurrencesOfString:@"_" withString:@":"];
        // 参数  200&300
        NSArray *params = nil;
        if (subpaths.count == 2) {
            params = [[subpaths lastObject] componentsSeparatedByString:@"&"];
        }
        // 调用
        [self performSelector:NSSelectorFromString(methodName) withObjects:params];
        
        return NO;
    }
    
    NSLog(@"想加载其他请求，不是想调用OC的方法");
    
    return YES;
  }
  
  - (id)performSelector:(SEL)selector withObjects:(NSArray *)objects
  {
    // 方法签名(方法的描述)
    NSMethodSignature *signature = [[self class] instanceMethodSignatureForSelector:selector];
    if (signature == nil) {
        [NSException raise:@"错误" format:@"%@方法找不到", NSStringFromSelector(selector)];
    }
    
    // NSInvocation : 利用一个NSInvocation对象包装一次方法调用（方法调用者、方法名、方法参数、方法返回值）
    NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature];
    invocation.target = self;
    invocation.selector = selector;
    
    // 设置参数
    NSInteger paramsCount = signature.numberOfArguments - 2; // 除self、_cmd以外的参数个数
    paramsCount = MIN(paramsCount, objects.count);
    for (NSInteger i = 0; i < paramsCount; i++) {
        id object = objects[i];
        if ([object isKindOfClass:[NSNull class]]) continue;
        [invocation setArgument:&object atIndex:i + 2];
    }
    
    // 调用方法
    [invocation invoke];
    
    // 获取返回值
    id returnValue = nil;
    if (signature.methodReturnLength) { // 有返回值类型，才去获得返回值
        [invocation getReturnValue:&returnValue];
    }
    
    return returnValue;
  }
  - (void)sendMessage:(NSString *)number number2:(NSString *)number2 number3:(NSString *)number3
   {
   NSLog(@"%s %@ %@ %@", __func__, number, number2, number3);
   }