从WKWebView捕获window.print（） [英] Capturing window.print() from a WKWebView

问题描述

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） 。有没有人知道实现这个目标的最佳方法？

I'm trying to capture the window.print() javascript call from a WKWebView with my app to actually show a print dialog and allow them to print from a button presented on the page (instead of a button inside my app). Does anyone know the best way to accomplish this?

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，我在那里找不到任何相关内容。

Currently, for me, clicking a link that calls window.print() just does nothing but fire the decidePolicyForNavigationAction delegate method and I couldn't find anything relevant in there.

推荐答案

在发布之后想出来（显然）......希望这有助于别人。

Figured it out just after posting (obviously)... Hopefully this helps someone else.

创建网络视图时......

When creating your web view...

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)

然后只是采用WKScriptMessageHandler协议在您的视图控制器和添加所需的方法...

Then just adopt the WKScriptMessageHandler protocol in your view controller and add the required method...

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)
        }
    }
}

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