Question

我正在尝试使用我的应用程序从WKWebView捕获window.print（）javascript调用，以实际显示打印对话框并允许它们从页面上显示的按钮打印（而不是我的应用程序内的按钮）。有谁知道实现这个目标的最佳方法？

目前，对我来说，单击一个调用window.print（）的链接只会触发decisionPolicyForNavigationAction委托方法，但我找不到任何相关内容。

Answer 1

在发布之后（显然）想出来......希望这有助于其他人。

创建网络视图时......

let configuration = WKWebViewConfiguration()
let script = WKUserScript(source: "window.print = function() { window.webkit.messageHandlers.print.postMessage('print') }", injectionTime: WKUserScriptInjectionTime.AtDocumentEnd, forMainFrameOnly: true)
configuration.userContentController.addUserScript(script)
configuration.userContentController.addScriptMessageHandler(self, name: "print")
self.webView = WKWebView(frame: CGRectZero, configuration: configuration)

然后在视图控制器中采用WKScriptMessageHandler协议并添加所需的方法......

func userContentController(userContentController: WKUserContentController, didReceiveScriptMessage message: WKScriptMessage) {
    if message.name == "print" {
        printCurrentPage()
    } else {
        println("Some other message sent from web page...")
    }
}

func printCurrentPage() {
    let printController = UIPrintInteractionController.sharedPrintController()
    let printFormatter = self.webView.viewPrintFormatter()
    printController?.printFormatter = printFormatter

    let completionHandler: UIPrintInteractionCompletionHandler = { (printController, completed, error) in
        if !completed {
            if let e = error? {
                println("[PRINT] Failed: \(e.domain) (\(e.code))")
            } else {
                println("[PRINT] Canceled")
            }
        }
    }

    if let controller = printController? {
        if UIDevice.currentDevice().userInterfaceIdiom == .Pad {
            controller.presentFromBarButtonItem(someBarButtonItem, animated: true, completionHandler: completionHandler)
        } else {
            controller.presentAnimated(true, completionHandler: completionHandler)
        }
    }
}

Answer 2

有一个undocumented委托用于挂钩window.print（）s

class MyApp: WKUIDelegate {
  func makeWebview() {
      ...
      self.webview.UIDelegate = self
  }
  func _webView(webView: WKWebView!, printFrame: WKFrameInfo) {
      println("JS: window.print()")
      printCurrentPage()
  }     
}

从WKWebView捕获window.print（）

2 个答案: