wkwebview 代理介绍

iOS 8引入了一个新的框架——WebKit，之后变得好起来了。在WebKit框架中，有WKWebView可以替换UIKit的UIWebView和AppKit的WebView，而且提供了在两个平台可以一致使用的接口。

WebKit框架使得开发者可以在原生App中使用Nitro来提高网页的性能和表现，Nitro就是Safari的JavaScript引擎。

WebKit 介绍

下面举个??

代码中有详细的注释

//
//  ViewController.m
//  WKWebView01
//
//  Created by njdby on 16/7/8.
//  Copyright © 2016年 njdby. All rights reserved.
//

#import "ViewController.h"
#import <WebKit/WebKit.h>
@interface ViewController ()<WKUIDelegate, WKNavigationDelegate,WKScriptMessageHandler>
@property (nonatomic, strong) WKWebView *webView;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];
    // 设置偏好设置
    config.preferences = [[WKPreferences alloc] init];
    // 默认为0
    config.preferences.minimumFontSize = 10;
    // 默认认为YES
    config.preferences.javaScriptEnabled = YES;
    // 在iOS上默认为NO，表示不能自动通过窗口打开
    config.preferences.javaScriptCanOpenWindowsAutomatically = NO;

    // web内容处理池，由于没有属性可以设置，也没有方法可以调用，不用手动创建
    config.processPool = [[WKProcessPool alloc] init];

    // 通过JS与webview内容交互
    config.userContentController = [[WKUserContentController alloc] init];

    // 注入JS对象名称AppModel，当JS通过AppModel来调用时，
    // 我们可以在WKScriptMessageHandler代理中接收到
    [config.userContentController addScriptMessageHandler:self name:@"AppModel"];

    self.webView = [[WKWebView alloc] initWithFrame:self.view.bounds
                                      configuration:config];
    [self.view addSubview:self.webView];

    // 导航代理
    self.webView.navigationDelegate = self;
    // 与webview UI交互代理
    self.webView.UIDelegate = self;

//    [self.webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"https://www.baidu.com"]]];

    NSURL *path = [[NSBundle mainBundle] URLForResource:@"test" withExtension:@"html"];
    [self.webView loadRequest:[NSURLRequest requestWithURL:path]];

    // 添加KVO监听
    [self.webView addObserver:self
                   forKeyPath:@"loading"
                      options:NSKeyValueObservingOptionNew
                      context:nil];
    [self.webView addObserver:self
                   forKeyPath:@"title"
                      options:NSKeyValueObservingOptionNew
                      context:nil];
    [self.webView addObserver:self
                   forKeyPath:@"estimatedProgress"
                      options:NSKeyValueObservingOptionNew
                      context:nil];

}

#pragma mark - WKUIDelegate
#if __IPHONE_OS_VERSION_MAX_ALLOWED > __IPHONE_9_0
- (void)webViewDidClose:(WKWebView *)webView {
    NSLog(@"%s", __FUNCTION__);
}
#endif

// 创建一个新的WebView（标签带有 target=‘_blank‘ 时，导致WKWebView无法加载点击后的网页的问题。）
- (WKWebView *)webView:(WKWebView *)webView createWebViewWithConfiguration:(WKWebViewConfiguration *)configuration forNavigationAction:(WKNavigationAction *)navigationAction windowFeatures:(WKWindowFeatures *)windowFeatures {
    // 接口的作用是打开新窗口委托
    WKFrameInfo *frameInfo = navigationAction.targetFrame;
    if (![frameInfo isMainFrame]) {
        [webView loadRequest:navigationAction.request];
    }
    return nil;
}

// 在JS端调用alert函数时，会触发此代理方法。
// JS端调用alert时所传的数据可以通过message拿到
// 在原生得到结果后，需要回调JS，是通过completionHandler回调
- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(void))completionHandler {
    NSLog(@"%s", __FUNCTION__);
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"alert" message:@"JS调用alert" preferredStyle:UIAlertControllerStyleAlert];
    [alert addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        completionHandler();
    }]];

    [self presentViewController:alert animated:YES completion:NULL];
    NSLog(@"%@", message);
}

// JS端调用confirm函数时，会触发此方法
// 通过message可以拿到JS端所传的数据
// 在iOS端显示原生alert得到YES/NO后
// 通过completionHandler回调给JS端
- (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(BOOL result))completionHandler {
    NSLog(@"%s", __FUNCTION__);

    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"confirm" message:@"JS调用confirm" preferredStyle:UIAlertControllerStyleAlert];
    [alert addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        completionHandler(YES);
    }]];
    [alert addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
        completionHandler(NO);
    }]];
    [self presentViewController:alert animated:YES completion:NULL];

    NSLog(@"%@", message);
}

// JS端调用prompt函数时，会触发此方法
// 要求输入一段文本
// 在原生输入得到文本内容后，通过completionHandler回调给JS
- (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(nullable NSString *)defaultText initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSString * __nullable result))completionHandler {
    NSLog(@"%s", __FUNCTION__);

    NSLog(@"%@", prompt);
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"textinput" message:@"JS调用输入框" preferredStyle:UIAlertControllerStyleAlert];
    [alert addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
        textField.textColor = [UIColor redColor];
    }];

    [alert addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        completionHandler([[alert.textFields lastObject] text]);
    }]];

    [self presentViewController:alert animated:YES completion:NULL];
}
#pragma mark - WKNavigationDelegate

#pragma mark - WKNavigationDelegate
/**
 *  在发送请求之前，决定是否跳转
 *
 *  @param webView          实现该代理的
 *  @param navigationAction 当前navigation
 *  @param decisionHandler  是否调转block
 */
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {
    NSString *hostname = navigationAction.request.URL.host.lowercaseString;
    if (navigationAction.navigationType == WKNavigationTypeLinkActivated
        && ![hostname containsString:@".baidu.com"]) {
        // 对于跨域，需要手动跳转
        [[UIApplication sharedApplication] openURL:navigationAction.request.URL];

        // 不允许web内跳转
        decisionHandler(WKNavigationActionPolicyCancel);
    } else {
       self.progressView.alpha = 1.0;
        decisionHandler(WKNavigationActionPolicyAllow);
    }

    NSLog(@"%s", __FUNCTION__);
}

/**
 *  在收到响应后，决定是否跳转
 *
 *  @param webView            实现该代理的webview
 *  @param navigationResponse 当前navigation
 *  @param decisionHandler    是否跳转block
 */
- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler {

    //    NSLog(@"%@",navigationResponse.response);

    // 如果响应的地址是百度，则允许跳转
    //    if ([navigationResponse.response.URL.host.lowercaseString isEqual:@"www.baidu.com"]) {
    //
    //        // 允许跳转
    //        decisionHandler(WKNavigationResponsePolicyAllow);
    //        return;
    //    }
    //    // 不允许跳转
    //    decisionHandler(WKNavigationResponsePolicyCancel);
    decisionHandler(WKNavigationResponsePolicyAllow);
}

/**
 *  页面开始加载时调用
 *
 *  @param webView    实现该代理的webview
 *  @param navigation 当前navigation
 */
- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(null_unspecified WKNavigation *)navigation {
    NSLog(@"%s", __FUNCTION__);
}

/**
 *  接收到服务器跳转请求之后调用
 *
 *  @param webView      实现该代理的webview
 *  @param navigation   当前navigation
 */
- (void)webView:(WKWebView *)webView didReceiveServerRedirectForProvisionalNavigation:(null_unspecified WKNavigation *)navigation {
    NSLog(@"%s", __FUNCTION__);
}

/**
 *  加载失败时调用
 *
 *  @param webView    实现该代理的webview
 *  @param navigation 当前navigation
 *  @param error      错误
 */
- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(null_unspecified WKNavigation *)navigation withError:(NSError *)error {
    NSLog(@"%s", __FUNCTION__);
}

/**
 *  当内容开始返回时调用
 *
 *  @param webView    实现该代理的webview
 *  @param navigation 当前navigation
 */
- (void)webView:(WKWebView *)webView didCommitNavigation:(null_unspecified WKNavigation *)navigation {
    NSLog(@"%s", __FUNCTION__);
}

/**
 *  页面加载完成之后调用
 *
 *  @param webView    实现该代理的webview
 *  @param navigation 当前navigation
 */
- (void)webView:(WKWebView *)webView didFinishNavigation:(null_unspecified WKNavigation *)navigation {
    NSLog(@"%s", __FUNCTION__);
}

// 导航失败时会回调
- (void)webView:(WKWebView *)webView didFailNavigation:(null_unspecified WKNavigation *)navigation withError:(NSError *)error {

}

// 对于HTTPS的都会触发此代理，如果不要求验证，传默认就行
// 如果需要证书验证，与使用AFN进行HTTPS证书验证是一样的
- (void)webView:(WKWebView *)webView didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *__nullable credential))completionHandler {
    NSLog(@"%s", __FUNCTION__);
    completionHandler(NSURLSessionAuthChallengePerformDefaultHandling, nil);
}

// 9.0才能使用，web内容处理中断时会触发
- (void)webViewWebContentProcessDidTerminate:(WKWebView *)webView {
    NSLog(@"%s", __FUNCTION__);
}

// 从web界面中接收到一个脚本时调用
#pragma mark - WKScriptMessageHandler
- (void)userContentController:(WKUserContentController *)userContentController
      didReceiveScriptMessage:(WKScriptMessage *)message {
    if ([message.name isEqualToString:@"AppModel"]) {
        // 打印所传过来的参数，只支持NSNumber, NSString, NSDate, NSArray,
        // NSDictionary, and NSNull类型
        NSLog(@"======>%@", message.body);
    }
}
#pragma mark - KVO
- (void)observeValueForKeyPath:(NSString *)keyPath
                      ofObject:(id)object
                        change:(NSDictionary<NSString *,id> *)change
                       context:(void *)context {
    if ([keyPath isEqualToString:@"loading"]) {
        NSLog(@"loading");
    } else if ([keyPath isEqualToString:@"title"]) {
        self.title = self.webView.title;
    } else if ([keyPath isEqualToString:@"estimatedProgress"]) {
        NSLog(@"progress: %f", self.webView.estimatedProgress);
        self.progressView.progress = self.webView.estimatedProgress;
    }

    // 加载完成
    if (!self.webView.loading) {
        // 手动调用JS代码
        // 每次页面完成都弹出来，大家可以在测试时再打开
        NSString *js = @"callJsAlert()";
        [self.webView evaluateJavaScript:js completionHandler:^(id _Nullable response, NSError * _Nullable error) {
            NSLog(@"response: %@ error: %@", response, error);
            NSLog(@"call js alert by native");
        }];

        NSString *jsData = @"calltoValue(‘参数‘)";
        [self.webView evaluateJavaScript:jsData completionHandler:^(id _Nullable response, NSError * _Nullable error) {
            NSLog(@"response: %@ error: %@", response, error);
            NSLog(@"------->call js alert by native");
        }];

        [UIView animateWithDuration:0.5 animations:^{
          self.progressView.alpha = 0;
        }];
    }
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

<!DOCTYPE html>
<html>
    <head>
        <title>iOS and Js</title>
        <style type="text/css">
            * {
                font-size: 40px;
            }
        </style>
    </head>

    <body>

        <div style="margin-top: 100px">
            <h1>Test how to use objective-c call js</h1><br/>
            <div><input type="button" value="call js alert" onclick="callJsAlert()"></div>
            <br/>
            <div><input type="button" value="Call js confirm" onclick="callJsConfirm()"></div><br/>
        </div>
        <br/>
        <div>
            <div><input type="button" value="Call Js prompt " onclick="callJsInput()"></div><br/>
            <div>Click me here: <a href="http://www.baidu.com">Jump to Baidu</a></div>
        </div>

        <br/>
        <div id="SwiftDiv">
            <span id="jsParamFuncSpan" style="color: red; font-size: 50px;"></span>
        </div>

        <script type="text/javascript">
            function callJsAlert() {
                alert(‘Objective-C call js to show alert‘);

                window.webkit.messageHandlers.AppModel.postMessage({body: ‘call js alert in js‘});
            }

        function callJsConfirm() {
            if (confirm(‘confirm‘, ‘Objective-C call js to show confirm‘)) {
                document.getElementById(‘jsParamFuncSpan‘).innerHTML
                = ‘true‘;
            } else {
                document.getElementById(‘jsParamFuncSpan‘).innerHTML
                = ‘false‘;
            }

            // AppModel是我们所注入的对象
            window.webkit.messageHandlers.AppModel.postMessage({body: ‘call js confirm in js‘});
        }

        function calltoValue(data){

            window.webkit.messageHandlers.AppModel.postMessage({body:data})
        }

        function callJsInput() {
            var response = prompt(‘Hello‘, ‘Please input your name:‘);
            document.getElementById(‘jsParamFuncSpan‘).innerHTML = response;

            // AppModel是我们所注入的对象
            window.webkit.messageHandlers.AppModel.postMessage({body: response});
        }
        </script>
    </body>
</html>

文／Ylang（简书作者）
原文链接：http://www.jianshu.com/p/b9728204e5f9
著作权归作者所有，转载请联系作者获得授权，并标注“简书作者”。