Android WebView onPageFinished BUG

Question

After update API (27) in Android OREO this code is no longer working:

 public void onPageFinished(WebView view, String url) {
     super.onPageFinished(view, url);
     view.loadUrl("javascript:(function() {document.getElementById(\"imPage\").style.display='none';})()");
 }

I have also tried with:

webView.loadUrl(
                    "javascript:(function() { " +

                            "document.addEventListener(\"DOMContentLoaded\", function(event) {" +

                            "document.getElementById(\"imPage\").style.display='none';" +

                            "});" +

                            "})()");

Element not hiding and debug return:

I/chromium: [INFO:CONSOLE(1)] "Uncaught TypeError: Cannot read property 'style' of null", source: mywebsite/ (1)

So I think the javascript is injected before loading page, this explains why the line is 1, because I have other code called after loading page is finished but this code is called when page is white, not loaded.

Answer 1

In my own project I have been using evaluateJavascript(script,null) in onPageFinished to hide html elements. view.loadUrl() Should work the same way.

If you don't need the function be called at later time you could simplify your JS string and instead of \\" try using ' .

public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
view.loadUrl("javascript:document.getElementById('imPage').style.display='none';");}

Answer 2

document.getElementById(\\"imPage\\") must be returning null .

So there is either no imPage element or you haven't loaded the page at the time.

I would suggest moving your entire js code into

document.addEventListener("DOMContentLoaded", function(event) { 
  //insert here
});

Answer 3

你必须启用如下的Javascript Seetings： -

view.getSettings().setJavaScriptEnabled(true); //Yes you have to do it