我有一个针对移动设备进行了优化的Web应用程序,可用于getUserMedia访问网络摄像头和麦克风资源。
getUserMedia
我WKWebView要将这个应用包装为A,因为我想提供本机应用体验。我知道,iOS不允许通过浏览器访问摄像机- 但有什么办法来获得权限的网络摄像头/麦克风与本机代码(沿着封装)和饲料这对Web应用程序-也许在某种程度上指向getUserMedia一个本地流源?
WKWebView
是的,看看cordova-plugin-iosrtc和cordova-plugin-wkwebview- engine。插件背后的想法如下:
1. 创建一个定义各种WebRTC类和函数的JavaScript文件(WebRTC.js),并将调用传递给WKWebView,例如:
(function() { if (!window.navigator) window.navigator = {}; window.navigator.getUserMedia = function() { webkit.messageHandlers.callbackHandler.postMessage(arguments); } })();
2. 在WKWebView中,在文档开始处插入脚本:
let contentController = WKUserContentController(); contentController.add(self, name: "callbackHandler") let script = try! String(contentsOf: Bundle.main.url(forResource: "WebRTC", withExtension: "js")!, encoding: String.Encoding.utf8) contentController.addUserScript(WKUserScript(source: script, injectionTime: WKUserScriptInjectionTime.atDocumentStart, forMainFrameOnly: true)) let config = WKWebViewConfiguration() config.userContentController = contentController webView = WKWebView(frame: CGRect.zero, configuration: config)
3. 收听从JavaScript发送的消息:
class ViewController: UIViewController, WKUIDelegate, WKNavigationDelegate, WKScriptMessageHandler { var webView: WKWebView! func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) { if message.name == "callbackHandler" { print(message.body) // make native calls to the WebRTC framework here } } }
4. 如果需要在JavaScript领域中执行成功或失败回调,请直接在WKWebView中评估函数调用:
webView.evaluateJavaScript("callback({id: \(id), status: 'success', args: ...})", completionHandler: nil)
这些回调需要 在 调用 _之前_存储在JavaScript中的哈希中postMessage,然后必须将哈希键发送到WKWebView。这是commandId插件中的。
postMessage
commandId
int exec_id = 0; function exec(success, failure, ...) { // store the callbacks for later if (typeof success == 'function' || typeof failure == 'function') { exec_id++; exec_callbacks[exec_id] = { success: success, failure: failure }; var commandId = exec_id; } webkit.messageHandlers.callbackHandler.postMessage({id: commandId, args: ...}) } // the native code calls this directly with the same commandId, so the callbacks can be performed and released function callback(opts) { if (opts.status == "success") { if (typeof exec_callbacks[opts.id].success == 'function') exec_callbacks[opts.id].success(opts.args); } else { if (typeof exec_callbacks[opts.id].failure == 'function') exec_callbacks[opts.id].failure(opts.args); } // some WebRTC functions invoke the callbacks multiple times // the native Cordova plugin uses setKeepCallbackAs(true) if (!opts.keepalive) delete exec_callbacks[opts.id]; }
5. 当然,为您的项目添加NSCameraUsageDescription和NSMicrophoneUsageDescription权限Info.plist。
NSCameraUsageDescription
NSMicrophoneUsageDescription
Info.plist
请记住,这是一项艰巨的任务,但这是将JavaScript,WKWebView和本机框架代码与异步回调桥接在一起的基本思路。