JavaScriptCore与WebView

Html中JS 与 Native交互情况

• Native调用JS
• JS调用Native

一. 获取WebView的JSContext

    func webViewDidFinishLoad(_ webView: UIWebView) {
        
        self.context = webView.value(forKeyPath: "documentView.webView.mainFrame.javaScriptContext") as? JSContext
    }

不同网页JSContext不同,只有在 webViewDidFinishLoad() 方法中获取,才能获取当前网页的JSContext

二. Native调用JS

Html中JS提供的接口

Native调用方法

     //本地调用JS方法
    @objc func nativeCallJS() {

        //方法一 (直接执行JS脚本)
        let scriptStr = "handler({'name':'小明', 'age':'18','job':'学生'})"
        let _ = self.context?.evaluateScript(scriptStr)
        
        //方法二 (获取函数,然后调用函数传参)
        let handleFunc = self.context?.objectForKeyedSubscript("handler")
        let paraDic = ["name":"小明", "age": 18, "job":"学生"] as [String : Any]
        let _ = handleFunc?.call(withArguments: [paraDic])

    }

三. JS调用Native

方式一: 使用Block(Swift 用闭包)

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

    //获取JS运行环境
    _context = [webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];
    //html调用无参数OC
    _context[@"test1"] = ^(){
        [self method1];
    };
    
    _context[@"test2"] = ^(){
        
        NSArray *args = [JSContext currentArguments];//传过来的参数
        NSString *name = args[0];
        NSString *str = args[1];
        [self method2:name and:str];
    };

}

方式二: 使用JSExport

@objc protocol SwiftBridgeProtocol: JSExport{
   
    //JS调用本地方法(无参数)
    func method1()
    func method2(_ title: String, _ message: String)
    func method3(_ handlerName: String)
}

@objc class SwiftBrige: NSObject, SwiftBridgeProtocol{
    
    weak var controller: UIViewController?
    weak var context   : JSContext?
    
    //JS调用本地方法(无参数)
    func method1()  {
        
        let controller = UIAlertController.init(title: "测试", message: "JS调用本地方法", preferredStyle: .alert)
        controller.addAction(UIAlertAction(title: "取消", style: .cancel, handler: nil))
        self.controller?.present(controller, animated: true, completion: nil)
    }
    
    //JS调用本地方法(传参数)
    func method2(_ title: String, _ message: String) {
        
        let controller = UIAlertController.init(title: title, message: message, preferredStyle: .alert)
        controller.addAction(UIAlertAction(title: "取消", style: .cancel, handler: nil))
        self.controller?.present(controller, animated: true, completion: nil)
    }
    
    //JS调用本地方法  本地方法回调JS方法
    func method3(_ handlerName: String){
        
        //回调参数
        let paraDic = ["name":"小明", "age": 18, "job":"学生"] as [String : Any]
        
        //获取JS回调函数
        let handleFunc = self.context?.objectForKeyedSubscript("\(handlerName)")
        
        //调用该函数
        let _ = handleFunc?.call(withArguments: [paraDic])
    }
}

项目代码Swift
项目代码OC