IOS 进阶之 WKWebView

来源：互联网发布：js删除指定class 编辑：程序博客网时间：2024/05/16 11:51

来源：o翻滚的牛宝宝o

链接：http://www.jianshu.com/p/4fa8c4eb1316

前言

Xcode8发布以后，编译器开始不支持IOS7，所以很多应用在适配IOS10之后都不在适配IOS7了，其中包括了很多大公司，网易新闻，滴滴出行等。因此，我们公司的应用也打算淘汰IOS7。

支持到IOS8，第一个要改的自然是用WKWebView替换原来的UIWebView。WKWebView有很多明显优势:

更多的支持HTML5的特性
官方宣称的高达60fps的滚动刷新率以及内置手势
将UIWebViewDelegate与UIWebView拆分成了14类与3个协议,以前很多不方便实现的功能得以实现。
https://developer.apple.com/library/mac/documentation/Cocoa/Reference/WebKit/ObjC_classic/index.html
Safari相同的JavaScript引擎
占用更少的内存

UIWebView

WKWebView

因此，使用WkWebview替换UIWebView还是很有必要的。

基本使用方法

WKWebView有两个delegate,WKUIDelegate 和 WKNavigationDelegate。WKNavigationDelegate主要处理一些跳转、加载处理操作，WKUIDelegate主要处理JS脚本，确认框，警告框等。因此WKNavigationDelegate更加常用。

比较常用的方法：

#pragma mark - lifeCircle
-(void)viewDidLoad{
    [superviewDidLoad];
    webView = [[WKWebViewalloc]init];
    [self.viewaddSubview:webView];
    [webViewmas_makeConstraints:^(MASConstraintMaker *make){
        make.left.equalTo(self.view);
        make.right.equalTo(self.view);
        make.top.equalTo(self.view);
        make.bottom.equalTo(self.view);
    }];
    webView.UIDelegate = self;
    webView.navigationDelegate = self;
    [webViewloadRequest:[NSURLRequestrequestWithURL:[NSURLURLWithString:@"http://www.baidu.com"]]];

}

#pragma mark - WKNavigationDelegate
// 页面开始加载时调用
-(void)webView:(WKWebView *)webViewdidStartProvisionalNavigation:(WKNavigation *)navigation{

}
// 当内容开始返回时调用
-(void)webView:(WKWebView *)webViewdidCommitNavigation:(WKNavigation *)navigation{

}
// 页面加载完成之后调用
-(void)webView:(WKWebView *)webViewdidFinishNavigation:(WKNavigation *)navigation{

}
// 页面加载失败时调用
-(void)webView:(WKWebView *)webViewdidFailProvisionalNavigation:(WKNavigation *)navigation{

}
// 接收到服务器跳转请求之后调用
-(void)webView:(WKWebView *)webViewdidReceiveServerRedirectForProvisionalNavigation:(WKNavigation *)navigation{

}
// 在收到响应后，决定是否跳转
-(void)webView:(WKWebView *)webViewdecidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponsedecisionHandler:(void(^)(WKNavigationResponsePolicy))decisionHandler{

    NSLog(@"%@",navigationResponse.response.URL.absoluteString);
    //允许跳转
    decisionHandler(WKNavigationResponsePolicyAllow);
    //不允许跳转
    //decisionHandler(WKNavigationResponsePolicyCancel);
}
// 在发送请求之前，决定是否跳转
-(void)webView:(WKWebView *)webViewdecidePolicyForNavigationAction:(WKNavigationAction *)navigationActiondecisionHandler:(void(^)(WKNavigationActionPolicy))decisionHandler{

    NSLog(@"%@",navigationAction.request.URL.absoluteString);
    //允许跳转
    decisionHandler(WKNavigationActionPolicyAllow);
    //不允许跳转
    //decisionHandler(WKNavigationActionPolicyCancel);
}
#pragma mark - WKUIDelegate
// 创建一个新的WebView
-(WKWebView *)webView:(WKWebView *)webViewcreateWebViewWithConfiguration:(WKWebViewConfiguration *)configurationforNavigationAction:(WKNavigationAction *)navigationActionwindowFeatures:(WKWindowFeatures *)windowFeatures{
    return[[WKWebViewalloc]init];
}
// 输入框
-(void)webView:(WKWebView *)webViewrunJavaScriptTextInputPanelWithPrompt:(NSString *)promptdefaultText:(nullable NSString *)defaultTextinitiatedByFrame:(WKFrameInfo *)framecompletionHandler:(void(^)(NSString *__nullableresult))completionHandler{
    completionHandler(@"http");
}
// 确认框
-(void)webView:(WKWebView *)webViewrunJavaScriptConfirmPanelWithMessage:(NSString *)messageinitiatedByFrame:(WKFrameInfo *)framecompletionHandler:(void(^)(BOOLresult))completionHandler{
    completionHandler(YES);
}
// 警告框
-(void)webView:(WKWebView *)webViewrunJavaScriptAlertPanelWithMessage:(NSString *)messageinitiatedByFrame:(WKFrameInfo *)framecompletionHandler:(void(^)(void))completionHandler{
    NSLog(@"%@",message);
    completionHandler();
}

OC与JS交互

WKWebview提供了API实现js交互不需要借助JavaScriptCore或者webJavaScriptBridge。使用WKUserContentController实现js native交互。简单的说就是先注册约定好的方法，然后再调用。

JS调用OC方法

oc代码(有误，内存不释放):

@interfaceViewController(){
    WKWebView *webView;
    WKUserContentController*userContentController;
}
@end
@implementationViewController
#pragma mark - lifeCircle
-(void)viewDidLoad{
    [superviewDidLoad];
    //配置环境
    WKWebViewConfiguration *configuration = [[WKWebViewConfigurationalloc]init];
    userContentController =[[WKUserContentControlleralloc]init];
    configuration.userContentController = userContentController;
    webView = [[WKWebViewalloc]initWithFrame:CGRectMake(0,0,100,100)configuration:configuration];
    //注册方法
    [userContentControlleraddScriptMessageHandler:self  name:@"sayhello"];//注册一个name为sayhello的js方法

    [self.viewaddSubview:webView];
    [webViewmas_makeConstraints:^(MASConstraintMaker *make){
        make.left.equalTo(self.view);
        make.right.equalTo(self.view);
        make.top.equalTo(self.view);
        make.bottom.equalTo(self.view);
    }];
    webView.UIDelegate = self;
    webView.navigationDelegate = self;
    [webViewloadRequest:[NSURLRequestrequestWithURL:[NSURLURLWithString:@"http://www.test.com"]]];
}
-(void)dealloc{
    //这里需要注意，前面增加过的方法一定要remove掉。
    [userContentControllerremoveScriptMessageHandlerForName:@"sayhello"];
}
#pragma mark - WKScriptMessageHandler
-(void)userContentController:(WKUserContentController *)userContentControllerdidReceiveScriptMessage:(WKScriptMessage *)message{
    NSLog(@"name:%@\\\\n body:%@\\\\n frameInfo:%@\\\\n",message.name,message.body,message.frameInfo);
}
@end

上面的OC代码如果认证测试一下就会发现dealloc并不会执行，这样肯定是不行的，会造成内存泄漏。原因是[userContentController addScriptMessageHandler:self name:@"sayhello"];这句代码造成无法释放内存。（ps:试了下用weak指针还是不能释放，不知道是什么原因。）因此还需要进一步改进，正确的写法是用一个新的controller来处理,新的controller再绕用delegate绕回来。

oc代码(正确写法):

@interfaceViewController(){
    WKWebView *webView;
    WKUserContentController*userContentController;
}
@end
@implementationViewController
#pragma mark - lifeCircle
-(void)viewDidLoad{
    [superviewDidLoad];
    //配置环境
    WKWebViewConfiguration *configuration = [[WKWebViewConfigurationalloc]init];
    userContentController =[[WKUserContentControlleralloc]init];
    configuration.userContentController = userContentController;
    webView = [[WKWebViewalloc]initWithFrame:CGRectMake(0,0,100,100)configuration:configuration];
    //注册方法
    WKDelegateController *delegateController = [[WKDelegateControlleralloc]init];
    delegateController.delegate = self;

    [userContentControlleraddScriptMessageHandler:delegateController  name:@"sayhello"];

    [self.viewaddSubview:webView];
    [webViewmas_makeConstraints:^(MASConstraintMaker *make){
        make.left.equalTo(self.view);
        make.right.equalTo(self.view);
        make.top.equalTo(self.view);
        make.bottom.equalTo(self.view);
    }];
    webView.UIDelegate = self;
    webView.navigationDelegate = self;
    [webViewloadRequest:[NSURLRequestrequestWithURL:[NSURLURLWithString:@"http://www.test.com"]]];
}
-(void)dealloc{
    //这里需要注意，前面增加过的方法一定要remove掉。
    [userContentControllerremoveScriptMessageHandlerForName:@"sayhello"];
}
#pragma mark - WKScriptMessageHandler
-(void)userContentController:(WKUserContentController *)userContentControllerdidReceiveScriptMessage:(WKScriptMessage *)message{
    NSLog(@"name:%@\\\\n body:%@\\\\n frameInfo:%@\\\\n",message.name,message.body,message.frameInfo);
}
@end

WKDelegateController代码：

#import
#import
@protocolWKDelegate

-(void)userContentController:(WKUserContentController *)userContentControllerdidReceiveScriptMessage:(WKScriptMessage *)message;

@end

@interfaceWKDelegateController : UIViewController

@property(weak,nonatomic)iddelegate;

@end

.m代码：

#import "WKDelegateController.h"

@interfaceWKDelegateController()

@end

@implementationWKDelegateController

-(void)viewDidLoad{
    [superviewDidLoad];
}

-(void)userContentController:(WKUserContentController *)userContentControllerdidReceiveScriptMessage:(WKScriptMessage *)message{
    if([self.delegaterespondsToSelector:@selector(userContentController:didReceiveScriptMessage:)]){
        [self.delegateuserContentController:userContentControllerdidReceiveScriptMessage:message];
    }
}

@end

h5代码:

<html>
<head>
    <script>
functionsay()
{
//前端需要用 window.webkit.messageHandlers.注册的方法名.postMessage({body:传输的数据} 来给native发送消息
    window.webkit.messageHandlers.sayhello.postMessage({body:'hello world!'});
}
</script>
</head>
    <body>
        <h1>helloworld</h1>
        <buttononclick="say()">sayhello</button>
    </body>

</html>

打印出的log：

name:sayhello
body:{
body = "hello world!";
}
frameInfo:{URL:http://www.test.com/ }>

注意点

addScriptMessageHandler要和removeScriptMessageHandlerForName配套出现，否则会造成内存泄漏。
h5只能传一个参数，如果需要多个参数就需要用字典或者json组装。

oc调用JS方法

代码如下：

-(void)webView:(WKWebView *)tmpWebViewdidFinishNavigation:(WKNavigation *)navigation{

    //say()是JS方法名，completionHandler是异步回调block
    [webViewevaluateJavaScript:@"say()"completionHandler:^(id _Nullable result,NSError *_Nullableerror){
        NSLog(@"%@",result);
    }];

}

h5代码同上。

WebViewJavascriptBridge

一般来说，一个好的UI总有一个大神会开发出一个好的第三方封装框架。WebViewJavascriptBridge的作者也做了一套支持WKWebView与JS交互的第三方框架:WKWebViewJavascriptBridge。

cocoaPods: pod ‘WebViewJavascriptBridge’, ‘~> 5.0.5’
github地址：https://github.com/marcuswestin/WebViewJavascriptBridge

主要方法如下：

//初始化方法
+(instancetype)bridgeForWebView:(WKWebView*)webView;
+(void)enableLogging;

//注册函数名
-(void)registerHandler:(NSString*)handlerNamehandler:(WVJBHandler)handler;

//调用函数名
-(void)callHandler:(NSString*)handlerName;
-(void)callHandler:(NSString*)handlerNamedata:(id)data;
-(void)callHandler:(NSString*)handlerNamedata:(id)dataresponseCallback:(WVJBResponseCallback)responseCallback;

//重置
-(void)reset;

//设置WKNavigationDelegate
-(void)setWebViewDelegate:(id)webViewDelegate;

基本的实现方法和上面写的差不多，就是封装了一下，有兴趣的童鞋可以自己pod下来使用。

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