Issue 559665 in chromium: Content in webview is not rendering on scroll on Android L and M

[chro...@googlecode.com]

Status: Unconfirmed
Owner: ----
Labels: Pri-2 Via-Wizard Type-Compat OS-Android

New issue 559665 by pardeep....@gmail.com: Content in webview is not
rendering on scroll on Android L and M
https://code.google.com/p/chromium/issues/detail?id=559665

Example URL:

Steps to reproduce the problem:
Steps:

1. Loading an website in WebView control.

Issue:
1. After load complete, I can see content rendered in view port. But once I
scroll down (or right), content doesn't render, I see only empty white/grey
area. Though I know that content is there.

This bug is seen on Android OS with version >= 5.0. On KitKat, it working
perfectly fine.

Also, in uiautomatorviewer I can see that there are VIEW elements with
non-zero co-ordinates. These VIEW elements are the one which were in View
port before scroll. Along with such VIEW elements I see other VIEW elements
which have co-ordinates (hence height, width) = 0.

Below is the code snippet:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
WebView.enableSlowWholeDocumentDraw();
setContentView(R.layout.activity_main);
mWebView = (WebView) findViewById(R.id.myWebView);
mWebView.getSettings().setJavaScriptEnabled(true);
mWebView.addJavascriptInterface(new WebAppInterface(), "external");
mWebView.setWebViewClient(new MyWebViewClient());
mWebView.setWebChromeClient(new MyWebChromeClient());
mWebView.loadUrl(myServiceUrl);
}

Enabling/disabling hardware rendering also didn't help.

Is this a known issue? Any fix/word around?

What is the expected behavior?

Issue:
1. After load complete, I can see content rendered in view port. But once I
scroll down (or right), content doesn't render, I see only empty white/grey
area. Though I know that content is there.

What went wrong?
Content should render on scroll

Does it occur on multiple sites: N/A

Is it a problem with a plugin? N/A

Did this work before? N/A

Does this work in other browsers? N/A

Chrome version: 46.0.2490.76 Channel: stable
OS Version: 5.1
Flash Version:

It is working fine on Android OS version < 5



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[chro...@googlecode.com]

Updates:
Owner: gsenn...@chromium.org

Comment #2 on issue 559665 by paulmil...@chromium.org: Content in webview

is not rendering on scroll on Android L and M
https://code.google.com/p/chromium/issues/detail?id=559665

passing to Gustav. If this only happens in a particular app, we'll need
that app to debug it. Source code would be best.

[chro...@googlecode.com]

Updates:
Labels: Needs-Feedback

Comment #3 on issue 559665 by gsenn...@chromium.org: Content in webview is

not rendering on scroll on Android L and M
https://code.google.com/p/chromium/issues/detail?id=559665

I can't reproduce this, @pardeep.itbhu do you have a minimal example
application we could use to test this?

[chro...@googlecode.com]

Comment #6 on issue 559665 by waldo.ga...@gmail.com: Content in webview is

not rendering on scroll on Android L and M
https://code.google.com/p/chromium/issues/detail?id=559665

I can reproduce this with http://4pda.ru/2016/02/12/276107/ , but only in
the landscape mode.

In the portrait mode there's a delay, but in the landscape mode it waits
until the line between rendered and not rendered goes out of the screen,
and only then renders. The grey gap appears to be exactly 1 screen tall.
When the grey gap occupies the full screen, it disappears. The problem is
that the parts separated by the grey gap cannot be shown together on the
same screen.

Philips S337, Android 5.1
Kernel 3.10.65-svn451 ateam1@ateam #1 Wed Nov 18 10:50:42 CST 2015



Attachments:
device-2016-02-13-081714.png 98.4 KB
device-2016-02-13-081944.png 204 KB
device-2016-02-13-082310.png 685 KB

[chro...@googlecode.com]

Comment #7 on issue 559665 by waldo.ga...@gmail.com: Content in webview is

not rendering on scroll on Android L and M
https://code.google.com/p/chromium/issues/detail?id=559665

As to the application, load the front page http://4pda.ru/page/1/

Document doc = Jsoup.connect(url).get(); // Jsoup

and then open a WebView on the first link. I suspect the glitch shows only
when there is not enough memory.

[chro...@googlecode.com]

Comment #8 on issue 559665 by waldo.ga...@gmail.com: Content in webview is

not rendering on scroll on Android L and M
https://code.google.com/p/chromium/issues/detail?id=559665

I also confirm that it sometimes does not render after modification.

rootView.getSettings().setJavaScriptEnabled(true);
rootView.setWebViewClient(new WebViewClient() {
@Override
public void onPageFinished(WebView view, String url) {
// remove the ads and navigation, they are not usable on
the phone

view.loadUrl("javascript:(function(){document.getElementById('topadbox').style.display='none';
})()");

view.loadUrl("javascript:(function(){document.getElementById('header').style.display='none';
})()");

view.loadUrl("javascript:(function(){document.getElementsByClassName('slider-news')[0].style.display='none';
})()");

and depending on the time required to render you either see grayish nothing
or the page of interest. It gets better after scrolling.