更新
他们说来自Docs
Fetch API 提供了一个用于获取资源的接口（包括
通过网络）。用过的人都会觉得很熟悉
XMLHttpRequest
您也可以使用以下字符串从 WKWebview 中获取 base64 字符串
let s = "path = document.getElementById(\"plugin\").src\n" +
"\n" +
"fetch(path).then(function (response) {\n" +
" response.body.getReader().read().then(function(result) {\n" +
" return btoa(String.fromCharCode.apply(null, result.value));\n" +
" }).then(function(b64) {\n" +
" window.webkit.messageHandlers.myInterface.postMessage(b64);\n" +
" });\n" +
"});"
fetch 和 xmlhttp 都是异步工作的。您需要做的就是等待处理完成后使用 javascript 到 ios 的桥 (WKScriptMessageHandler) 将其传递给 Swift
使用以下代码将 base64 字符串从 javascript 获取到 Swift。
我正在使用WKScriptMessageHandler 从Javascript 当base64 字符串准备好使用时获取回调。在 String 中，您只需传递 pdf 的 url，它会执行 ajax 请求来获取 pdf 文件，然后将其转换为 base64 字符串。
import UIKit
import WebKit
class ViewController: UIViewController {
@IBOutlet weak var btnPDF: UIButton!
@IBOutlet weak var webViewParentView: UIView!
var activityIndicator: UIActivityIndicatorView?
var webView: WKWebView!
@objc func didSelect(_ sender: UIView){
let s="var xhr = new XMLHttpRequest();\n" +
"xhr.open(\'GET\', \"https://codingexceptions.com/wkwebview/dummy.pdf\", true);\n" +
"\n" +
"xhr.responseType = \'arraybuffer\';\n" +
"\n" +
"xhr.onload = function(e) {\n" +
" if (this.status == 200) {\n" +
" var uInt8Array = new Uint8Array(this.response);\n" +
" var i = uInt8Array.length;\n" +
" var binaryString = new Array(i);\n" +
" while (i--)\n" +
" {\n" +
" binaryString[i] = String.fromCharCode(uInt8Array[i]);\n" +
" }\n" +
" var data = binaryString.join(\'\');\n" +
"\n" +
" var base64 = window.btoa(data);\n" +
"\n" +
"window.webkit.messageHandlers.myInterface.postMessage(base64);" +
"\n" +
" }\n" +
"};\n" +
"\n" +
"xhr.send();\n"
webView.configuration.userContentController.add(self, name: "myInterface")
webView?.evaluateJavaScript(s, completionHandler: {(string,error) in
print(error ?? "no error")
})
}
func setupWebView(){
webView = WKWebView.init(frame: CGRect(x: 0, y: 0, width: webViewParentView.frame.width, height: webViewParentView.frame.height))
webView.navigationDelegate = self
webViewParentView.addSubview(webView)
activityIndicator = UIActivityIndicatorView(activityIndicatorStyle: .gray)
activityIndicator?.center = self.view.center
self.view.addSubview(activityIndicator!)
webView.load(URLRequest(url: URL(string: "https://codingexceptions.com/wkwebview/index.php")!))
activityIndicator?.startAnimating()
}
override func viewDidLoad() {
super.viewDidLoad()
btnPDF.addTarget(self, action: #selector(self.didSelect(_:)), for: .touchUpInside)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
setupWebView()
}
}
extension ViewController: WKScriptMessageHandler{
func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
print("Message received: \(message.name) with body: \(message.body)")
}
}
extension ViewController: WKNavigationDelegate{
func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
self.activityIndicator?.stopAnimating()
self.activityIndicator?.removeFromSuperview()
self.activityIndicator = nil
}
}
更新：从 @Tarun 的答案中指出的 embed 标记获取源代码
只需将下面的 行放在字符串变量 s 的开头 并在 xhr.open 中传递 url
var url = document.getElementById("plugin").src