js与native交互

UIWebView

Native调用JS,使用stringByEvaluatingJavaScriptFromString来解释执行js脚本。

//script即为要执行的js方法名称

- (NSString *)stringByEvaluatingJavaScriptFromString:(NSString *)script;

PS：苹果推荐iOS8之后的app使用WKWebView来代替UIWebView，同时也使用方法 evaluateJavaScript:completionHandler:来替代stringByEvaluatingJavaScriptFromString，因为会一直等待stringByEvaluatingJavaScriptFromString方法执行完毕

JS调用Native，需要通过UIWebView拦截跳转请求并判断请求头是否是协商好的协议头来判断是否是JS发起调用Native的请求。

- webView:shouldStartLoadWithRequest:navigationType:

function callNative{

    var url = ”callNative://nslogHelloWord“

     window.location.href = url;

}

- (BOOL)webView:(UIWebView*)webView shouldStartLoadWithRequest:(NSURLRequest*)request navigationType:(UIWebViewNavigationType)navigationType{

    //callNative 为约定好的协议头，如果是，则页面不进行跳转

    if ([request.URL.scheme isEqualToString:@"callNative"]) {

        NSlog(@"Hello World");

        return NO;

    }

    //不是自定义协议头，跳转页面

    return YES;

}

WKWebView

苹果自iOS8、OS X 10.10推荐使用WKWebView来代替原先的UIWebView，WKWebView拥有更快的加载速度和性能，更低的内存占用，同时更细致的代理分类来满足不同需要的调用。

Native调用JS,使用方法evaluateJavaScript:completionHandler:来解释执行脚本。

//javaScriptString要执行的js方法

//completionHandler执行结束回调或者发生错误时回调

- (void)evaluateJavaScript:(NSString *)javaScriptString completionHandler:(void (^)(id, NSError *error))completionHandler;

JS调用Native，通过代理WKScriptMessageHandler来实现调用。

#import "WKWVController.h"

#import <WebKit/WebKit.h>

@interface WKWVController ()<WKUIDelegate,WKScriptMessageHandler>

@property (strong, nonatomic) WKWebView *webView;

@end

@implementation WKWVController

- (void)viewDidLoad {

    [super viewDidLoad];

    // js配置

    WKUserContentController *userContentController = [[WKUserContentController alloc] init];

    //监听方法名

    [userContentController addScriptMessageHandler:self name:@"jsCallOC"];

    // WKWebView的配置

    WKWebViewConfiguration *configuration = [[WKWebViewConfiguration alloc] init];

    configuration.userContentController = userContentController;

    // 显示WKWebView

    _webView = [[WKWebView alloc] initWithFrame:[UIScreen mainScreen].bounds configuration:configuration];

    _webView.UIDelegate = self; // 设置WKUIDelegate代理

    [self.view addSubview:_webView];

    NSURL *url = [[NSBundle mainBundle] URLForResource:@"index" withExtension:@"html"];

    NSURLRequest *urlRequest = [NSURLRequest requestWithURL:url];

    [_webView loadRequest:urlRequest];

}

// WKScriptMessageHandler protocol?

- (void)userContentController:(WKUserContentController *)userContentController

      didReceiveScriptMessage:(WKScriptMessage *)message

{

    NSLog(@"方法名:%@", message.name);

    NSLog(@"参数:%@", message.body);

    // 方法名

    NSString *methods = [NSString stringWithFormat:@"%@", message.name];

    SEL selector = NSSelectorFromString(methods);

    // 调用方法

    if ([self respondsToSelector:selector]) {

        [self performSelector:selector withObject:message.body];

    } else {

        NSLog(@"未实行方法：%@", methods);

    }

}

- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

}

- (void)jsCallOC{

    [self.webView evaluateJavaScript:@"wkNativeCallJS('嘿嘿')" completionHandler:^(id _Nullable data, NSError * _Nullable error) {

        NSLog(@"我执行完毕");

    }];

}

<!DOCTYPE html>

<html lang="en">

    <head>

        <meta charset="UTF-8">

            <title>网页</title>

    </head>

    <body>

        <button onclick="wkWebViewTestClick()" style="height: 100px;width: 200px;">点我调用native方法</button>

        function wkNativeCallJS(info){

            //wkwebview 不直接使用js的alert 显示不了

            //http://stackoverflow.com/questions/34185339/wkwebview-javascript-confirm-and-alert-not-working

            console.log(info);

        }

      function wkWebViewTestClick(){

            // 复杂数据

            var list = [1,2,3];

            var dict = {"name":"阳君", "qq":"937447974"};

            // JS通知WKWebView，jsCallOC即为在controller中注册的方法名称

            window.webkit.messageHandlers.jsCallOC.postMessage(dict);

        }

        </script>

    </body>

</html>

JavaScriptCore方式相互调用

在iOS7.0中苹果公司增加了JS利器JavaScriptCore框架，JavaScriptCore提供了很多灵活的本地OC与JS的交互方式，通过JSContext和JSValue来完成的，JSContext是一个WebView中js代码运行环境，js可以通过JSContext以block和通过继承JSExport代理，自定义实现代理方法。

#import "WVController.h"

#import <JavaScriptCore/JavaScriptCore.h>

@protocol JSObjcDelegate <JSExport>

-(void)logInfo:(NSString*)info;

@end

@interface WVController ()<JSObjcDelegate>

@property (weak, nonatomic) IBOutlet UIWebView *wv;

@property (nonatomic, strong) JSContext *jsContext;

@end

@implementation WVController

- (void)viewDidLoad {

    [super viewDidLoad];

    NSString* path = [[NSBundle mainBundle]pathForResource:@"index" ofType:@"html"];

    NSURL* url = [NSURL URLWithString:path];

    NSURLRequest* request = [NSURLRequest requestWithURL:url];

    [self.wv loadRequest:request];

}

//oc调用js

- (IBAction)callJSMethod:(id)sender {

    [self.wv stringByEvaluatingJavaScriptFromString:@"wvNativeCallJS()"];

}

//使用url拦截

-(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{

    if ([request.URL.scheme isEqualToString:@"callnative"]) {

        NSLog(@"hello world");

        return false;

    }

    return true;

}

- (void)webViewDidFinishLoad:(UIWebView *)webView {

    //获取上下文对象

    self.jsContext = [webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];

    self.jsContext[@"Objc"] = self;

    self.jsContext.exceptionHandler = ^(JSContext *context, JSValue *exceptionValue) {

        context.exception = exceptionValue;

        NSLog(@"异常信息：%@", exceptionValue);

    };

    //直接使用block方式执行oc方法

    self.jsContext[@"logHello"] = ^(){

        NSLog(@"hello");

    };

}

//使用代理接口方式执行native方法

-(void)logInfo:(NSString *)info{

    NSLog(@"js传来的参数%@",info);

    JSValue* callback = self.jsContext[@"wvNativeCallJS"];

    [callback callWithArguments:nil];

}

@end

<!DOCTYPE html>

<html lang="en">

    <head>

        <meta charset="UTF-8">

            <title>网页</title>

    </head>

    <body>

//1

      <button onclick="Objc.logInfo('哈哈')" style="height: 100px;width: 200px;">点我调用native方法</button>

//2

<!--        <button onclick="logHello()" style="height: 100px;width: 200px;">点我调用native方法</button>-->

        <script type="text/javascript">

            function wvNativeCallJS(){

                alert("wvController");

            }

        </script>

    </body>

</html>

DEMO：下载Demo

参考：