oc调用js方法

evaluateJavaScript: completionHandler:

h5页面中有如下js方法

function sayHello(name){
  let message = 'hello,'+name+'!!!'
  alert(message)
  console.log(message)
  return message
}

在WKWebView中通过oc调用这个js方法:

-(void)runJSFunction{
    NSString *name = @"tom";
    NSString *jsFunctionStr = [NSString stringWithFormat:@"sayHello('%@');",name]; //@"sayHello('tom');"
    [self.webView evaluateJavaScript:jsFunctionStr completionHandler:^(id _Nullable result, NSError * _Nullable error) {
        NSLog(@"%@ - %@",result, [result class]);  //打印结果:hello,tom!!! - __NSCFString
    }];
}

js调用oc方法

假设 原生端向前端提供了一个方法名为ocTestFunction的方法, 前端与原生端的通信过程如下.

原生端
// handler 为实现了 WKScriptMessageHandler协议的对象
ScriptMessageHandler *handler = [ScriptMessageHandler new];
[self.webView.configuration.userContentController addScriptMessageHandler:handler name: ocTestFunction];

注意需要在浏览器释放时移除WKScriptMessageHandler

-(void)dealloc{    
    // 移除js交互引用
    [self.webView.configuration.userContentController removeScriptMessageHandlerForName:ocTestFunction];
}

前端js调用的格式:
window.webkit.messageHandlers.nativeFunctionName.postMessage

function jsToOcWithPrams(message) {
  window.webkit.messageHandlers.ocTestFunction.postMessage({
    body:{
      "func" : "sayHello",
      "data" : {"message" : message}
    }
  })
}

实现了 WKScriptMessageHandler协议的对象需要实现以下方法:
- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message;

-(void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message{
    //jsToOcNoPrams/jsToOcWithPrams
    
    // message.name  message.body
    NSLog(@"name:%@\n body:%@\n frameInfo:%@\n",message.name,message.body,message.frameInfo);
    
    //用message.body获得JS传出的参数体
    NSDictionary *parameter = message.body;
    NSString *functionName = parameter[@"func"];
    NSDictionary *functionPrams = parameter[@"data"];
    
    if ([functionName isEqualToString:@"sayHello"]) {
        [self alertMessage:[NSString stringWithFormat:@"hello, %@",functionPrams[@"message"]]];
    }
}

js注入

在webview初始化时, 向webView注入一个js方法, 这样前端页面都可以访问这个js方法了

NSString *jSString = @"function  testFunction() { console.log('hello 2'); alert('this si test function'); }";
WKUserScript *wkUScript = [[WKUserScript alloc] initWithSource:jSString injectionTime:WKUserScriptInjectionTimeAtDocumentEnd forMainFrameOnly:YES];
[config.userContentController addUserScript:wkUScript];