在上一篇文章中,我總結(jié)了UIWebView與Native進(jìn)行交互的三種常用方式. 今天繼續(xù)總結(jié)WKWebView與Native進(jìn)行交互的方式.

蘋果在iOS8以后推出了WebKit框架, WKWebView用來負(fù)責(zé)網(wǎng)頁的渲染、展示. 與UIWebView相比, WKWebView更加快捷, 內(nèi)存占用更小, 也支持更多的HTML特性.

一、協(xié)議攔截

(1)絮姆、JSToNative

• 邏輯: 點(diǎn)擊HTML中的按鈕, 傳遞參數(shù)到Native, Native展示接收到的數(shù)據(jù)

• 實(shí)現(xiàn):
  JS調(diào)用OC并傳遞參數(shù)

• JS代碼:

<div style="margin-top: 20px">
        <button onclick = "buttonClick()" style = "font-size: 30px; width: 300px; height: 100px" >
            點(diǎn)我~
        </button>
    </div>

function buttonClick() {
            var message = '獲取到html按鈕點(diǎn)擊事件';
            clickSuccess(message);
        }
        function clickSuccess(message) {
            var param = 'JS傳遞過來了參數(shù):1234';
            JSTransferOC(message, param);
        }
    
        function JSTransferOC(message, param) {
            var url = 'JSTransferOC://' + message +'?'+ param;
            window.location.href = url;
        }

• OC代碼:

#import <WebKit/WebKit.h>

#pragma mark - WKNavigationDelegate

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {
    
    //!< 判斷是否是約定好的scheme
    if ([navigationAction.request.URL.scheme caseInsensitiveCompare:@"JSTransferOC"] == NSOrderedSame) {
        [self presentAlertWithTitle:navigationAction.request.URL.host message:navigationAction.request.URL.query handler:^(UIAlertAction * _Nonnull action) {
            decisionHandler(WKNavigationActionPolicyCancel);
        }];
    } else {
        decisionHandler(WKNavigationActionPolicyAllow);
    }
    //!< 注意這里的 decisionHandler()必須調(diào)用, 否則會(huì)崩潰. 相當(dāng)于UIWebView中的 - shouldStartLoadWithRequest 方法中 返回YES Or NO 是否允許跳轉(zhuǎn)
}

• 原理:
  • JS與Native定義好入口函數(shù)- JSTransferOC();
  • OC遵循< WKNavigationDelegate >協(xié)議, 實(shí)現(xiàn)- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler代理方法, 這個(gè)代理方法在webView每次load前都會(huì)調(diào)用;
  • 在代理方法中, 攔截每次請求, 判斷request.url.scheme是否是約定好的scheme;
  • 如果是約定好的scheme, 那么Native解讀url, 讀取參數(shù);

(2)崔赌、Native調(diào)用JS, 并傳遞參數(shù)

• 邏輯: 點(diǎn)擊Native登錄按鈕, 登錄成功后, 將數(shù)據(jù)傳遞給JS, JS展示獲取的數(shù)據(jù).

• 實(shí)現(xiàn):
  Native將獲取的數(shù)據(jù)傳遞給JS

• JS代碼:

 <div style = "font-size: 30px;margin-top: 20px">
        回調(diào)數(shù)據(jù)展示:
    </div>

    <div id = "returnValue" style = "font-size: 30px; border: 1px dotted; height: 100px;margin-top: 20px">

    </div>

//!< OC調(diào)用JS, 并回傳給JS參數(shù), JS展示
        function OCTransferJS(message, param) {
            document.getElementById('returnValue').innerHTML = message + param;
        }

• OC代碼:

- (void)login:(UIButton *)sender {
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        //!< 注意: evaluateJavaScript 只有在webView全部load完成后才能執(zhí)行
        [self.webView evaluateJavaScript:[NSString stringWithFormat:@"OCTransferJS('OC調(diào)用JS代碼, 并傳遞參數(shù);', 'OC傳遞來了參數(shù):12345678')"] completionHandler:^(id _Nullable response, NSError * _Nullable error) {
        }];
    });
}

• 原理:
  • JS和Native定義好函數(shù)OCTransferJS, 作為入口函數(shù);
  • Native通過-evaluateJavaScript: completionHandler:方法, 執(zhí)行一段JS代碼, 傳遞參數(shù),
  • JS展示傳遞來的參數(shù);

二、WKScriptMessageHandler協(xié)議

WKScriptMessageHandler, 官方釋義為: A class conforming to the WKScriptMessageHandler protocol provides a method for receiving messages from JavaScript running in a webpage, 為遵循了WKScriptMessageHandler協(xié)議的類, 提供了一個(gè)用于從webpage網(wǎng)頁中運(yùn)行的JavaScript接收消息的方法

(1)木西、JSToNative

• 邏輯: 點(diǎn)擊HTML中的按鈕, 傳遞參數(shù)到Native, Native接收參數(shù)并展示;

• 實(shí)現(xiàn):
  JSToNative

• JS代碼:

<div style="margin-top: 20px">
        <button onclick = "WKScriptMessageHandlerBtnClick()" style = "font-size: 30px; width: 500px; height: 100px" >
            WKScriptMessageHandlerBtn
        </button>
    </div>

//!< 通過WKScriptMessageHandler的方式進(jìn)行交互
        function WKScriptMessageHandlerBtnClick() {
            var message = '獲取到HTML按鈕點(diǎn)擊事件';
            clickComplete(message);
        }
        function clickComplete(message) {
            var param = 'JS傳遞來了參數(shù):12345';
            //!< 與webKit進(jìn)行交互時(shí), JS代碼中要這樣調(diào)用
            window.webkit.messageHandlers.JSToOC.postMessage(message + '     ' + param);
        }

• OC代碼:

#import <WebKit/WebKit.h>
@interface WKWebViewVC ()<WKUIDelegate, WKNavigationDelegate, WKScriptMessageHandler>

//!< 為WKUserContentController添加name為'JSToOC'的 ScriptMessageHandler;
    WKUserContentController *userC = [[WKUserContentController alloc] init];
    [userC addScriptMessageHandler:self name:@"JSToOC"];
    
    //!< 配置WKWebViewConfiguration;
    WKWebViewConfiguration *configuretion = [[WKWebViewConfiguration alloc] init];
    configuretion.userContentController = userC;
    
    //!< 使用WKWebViewConfiguration初始化
    self.webView = [[WKWebView alloc] initWithFrame:self.view.frame configuration:configuretion];

#pragma mark - WKScriptMessageHandler

- (void)userContentController:(WKUserContentController *)userContentController didReceiveScriptMessage:(WKScriptMessage *)message {
    if ([message.name caseInsensitiveCompare:@"JSToOC"] == NSOrderedSame) {
        [self presentAlertWithTitle:message.name message:message.body handler:nil];
    }
}

• 原理:
  • JS和Native約定好入口函數(shù):JSToOC;
  • JS中通過window.webkit.messageHandlers.JSToOC.postMessage(message + ' ' + param)的方式, 調(diào)用JSToOC函數(shù);
  • OC通過- addScriptMessageHandler: name:方法來監(jiān)聽name為JSToOC的方法;
  • OC類遵循WKScriptMessageHandler協(xié)議, 并實(shí)現(xiàn)代理方法- userContentController: didReceiveScriptMessage:, 在代理方法中獲取數(shù)據(jù)message.body;

注: - addScriptMessageHandler: name:會(huì)引起循環(huán)引用, 應(yīng)該在合適的時(shí)間去-removeScriptMessageHandlerForName:;

(2)、NativeToJS:

和上述方法相同, 都是通過-evaluateJavaScript:completionHandler:來執(zhí)行一段JS字符串;

三、WKUIDelegate協(xié)議

經(jīng)常有在群里看到朋友抱怨, WKWebView中, JS調(diào)用alert()君珠、confirm()和prompt()函數(shù)沒有反應(yīng)。 這是由于WKWebView的特性, native必須實(shí)現(xiàn)WKUIDelegate的三個(gè)代理方法, 才能正常彈出提示框.

(1)赁项、提示框的彈出

• 邏輯: 點(diǎn)擊html中的相應(yīng)按鈕, 在native中彈出提示框;

• 實(shí)現(xiàn):
  JS通過WKWebView調(diào)用彈窗

• JS代碼:

<div id = "returnValue" style = "font-size: 30px; border: 1px dotted; height: 100px;margin-top: 20px">
    </div>

<div style="margin-top: 20px">
        <button onclick = "alertButtonClick()" style = "font-size: 30px; width: 300px; height: 100px" >
            alertButton
        </button>
    </div>

    <div style="margin-top: 20px">
        <button onclick = "confirmButtonClick()" style = "font-size: 30px; width: 300px; height: 100px" >
            confirmButton
        </button>
    </div>

    <div style="margin-top: 20px">
        <button onclick = "promptButtonClick()" style = "font-size: 30px; width: 300px; height: 100px" >
            promptButton
        </button>
    </div>

function alertButtonClick() {
           var result = alert('點(diǎn)擊了HTML中的alertButton');
           document.getElementById('returnValue').innerHTML = result;
        }
    
        function confirmButtonClick() {
           var result = confirm('點(diǎn)擊了HTML中的confirmButton');
           document.getElementById('returnValue').innerHTML = result;
        }
    
        function promptButtonClick() {
           var result = prompt('點(diǎn)擊了HTML中的promptButton', '確定');
           document.getElementById('returnValue').innerHTML = result;
           
        }

• OC代碼:
  • alert:

#pragma mark - WKUIDelegate

- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(void))completionHandler {
    [self presentAlertWithTitle:@"title" message:message handler:^(UIAlertAction * _Nonnull action) {
        completionHandler();
    }];
    
}

• confirm:

- (void)webView:(WKWebView *)webView runJavaScriptConfirmPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(BOOL))completionHandler {
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Confirm" message:message preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
        completionHandler(NO);
    }];
    UIAlertAction *confirmAction = [UIAlertAction actionWithTitle:@"確認(rèn)" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        completionHandler(YES);
    }];
    [alertController addAction:cancelAction];
    [alertController addAction:confirmAction];
    [self presentViewController:alertController animated:YES completion:nil];
}

• TextInputPanel:

- (void)webView:(WKWebView *)webView runJavaScriptTextInputPanelWithPrompt:(NSString *)prompt defaultText:(NSString *)defaultText initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)(NSString * _Nullable))completionHandler {
    
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:prompt message:nil preferredStyle:UIAlertControllerStyleAlert];
    [alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
        textField.placeholder = defaultText;
    }];
    UIAlertAction *confirmAction = [UIAlertAction actionWithTitle:@"確認(rèn)" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        completionHandler(alertController.textFields[0].text);
    }];
    [alertController addAction:confirmAction];
    [self presentViewController:alertController animated:YES completion:nil];
    
}

• 原理:
  • html中創(chuàng)建各個(gè)彈窗需要的按鈕, 并調(diào)用彈窗的方法;
  • native中實(shí)現(xiàn)WKUIDelegate中的代理方法, 調(diào)用原生彈窗;