Michael Svit Michael Svit - 3 months ago 15
Android Question

WebView loads URL 10 times slower than phone's Chrome browser

I've been trying to figure this one out for quite a while, and yet haven't found a solution.

Inside my app I'm extracting a website's HTML through an invisible WebView component. I do not need to view the website, just get the html it loads. The website uses JavaScript to load all of its content, and therefore I need a full web renderer in order to execute that JavaScript. In its current form, I'm overriding the WebViewClient's onPageFinished method to inject JavaScript that dumps the html into a JavaScriptInterface which then processes it.

My main issue here is that when I load this URL inside my app it would take about 8 seconds, whereas loading the exact same URL in the phone's chrome browser it takes less than a second. Any suggestions as to what might be the problem?

If it could be of any help, the JavaScript that gets executed stores a cookie inside the WebView, and then tries to retrieve it, and only if it finds said cookie (which has a short expiration time) it would load the site's HTML. In this case it actually loads data formatted with JSON (about 370k characters).

Relevant WebView code:

private void initWebView(View view) {
class JSInterface{
@JavascriptInterface
public void processHTML(String scheduleJSONResponse){
if(scheduleJSONResponse.length() > 10000){
Log.d(LOG_TAG, "Finished loading JSON");
}
}
}
webView = (WebView) view.findViewById(R.id.fragment_movies_web_view);
webView.getSettings().setJavaScriptEnabled(true);
webView.addJavascriptInterface(new JSInterface(), "Android");
webView.setWebViewClient(new WebViewClient(){
@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
Log.d(LOG_TAG, "Page finished loading");
webView.loadUrl("javascript:window.Android.processHTML(document.getElementsByTagName('html')[0].textContent);");
}
});
webView.loadUrl(url);
}


As for why I check that the length is more than 10k characters: Sometimes onPageFinished would get called more than once, with the first call being before the JavaScript is executed, and so I get HTML containing the script to be executed which isn't what I need.

Thanks in advance for any help!




A logcat to demonstrate the issue:

08-18 22:32:23.623 26238-26238/com.michaelsvit.kolnoa I/Timeline: Timeline: Activity_idle id: android.os.BinderProxy@1e4dc08f time:502735009
08-18 22:32:23.638 26238-26238/com.michaelsvit.kolnoa W/cr_BindingManager: Cannot call determinedVisibility() - never saw a connection for the pid: 26238
08-18 22:32:31.336 26238-26238/com.michaelsvit.kolnoa D/MovieGridFragment: Page finished loading


Current code after simplifying it:

private void initWebView(View view) {
class JSInterface{
@JavascriptInterface
public void processHTML(String scheduleJSONResponse){
if(scheduleJSONResponse.length() > 10000){
Log.d(LOG_TAG, "Finished loading JSON");
}
}
}
webView = (WebView) view.findViewById(R.id.fragment_movies_web_view);
webView.getSettings().setJavaScriptEnabled(true);
//webView.addJavascriptInterface(new JSInterface(), "Android");
webView.setWebViewClient(new WebViewClient(){
@Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
Log.d(LOG_TAG, "Page finished loading");
//webView.loadUrl("javascript:window.Android.processHTML(document.getElementsByTagName('html')[0].textContent);");
}
});
}

Answer
  through an invisible WebView component.. 

What when it is visible?

Try it!