[WebView] callback methods of onPageStarted & onPageFinished

[Callia]

HI, 

I'd like to discuss the calling method for page loading & page finished on WebView.

For a page loading, chromium uses UI main thread to run 2 important callbacks in order to notify WebView that page loading timing change.

1. onPageStarted (notify page is staring to load)

    - InterceptNavigationDelegate::ShouldIgnoreNavigation --> AwContents$InterceptNavigationDelegateImpl.shouldIgnoreNavigation -->post a message(async call) do to WebViewContentsClientAdapter.onPageStarted

2. onPageFinished (notify page loading done)

    - WebContentsObserverProxy.didFinishLoad --> blocking call WebViewContentsClientAdapter.onPageFinished

 

Because it’s a async call to run WebViewContentsClientAdapter.onPageStarted, it dose not gurantee that WebViewContentsClientAdapter.onPageStarted executing before WebViewContentsClientAdapter.onPageFinished.

Sometimes, page loading callback is out of order, like this issue.

 

 

In order to consistent callback sequence, onPageStartedd and onPageFinished should BOTH are blocking or BOTH are async call. How about changing to use post message (async call) to trigger onPageFinished?

Thanks you.

 

Example:

/android_webview/java/src/org/chromium/android_webview/AwWebContentObserver.java

    @Override

    public void didFinishLoad(long frameId, String validatedUrl, boolean isMainFrame) {

        AwContentsClient client = mAwContentsClient.get();

        if (client == null) return;

        String unreachableWebDataUrl = AwContentsStatics.getUnreachableWebDataUrl();

        boolean isErrorUrl =

                unreachableWebDataUrl != null && unreachableWebDataUrl.equals(validatedUrl);

        if (isMainFrame && !isErrorUrl) {

            //

            //client.onPageFinished(validatedUrl);

            //

            client.getCallbackHelper().postOnPageFinished(validatedUrl);

        }

    }

[Mikhail Naganov]

Hi Callia,

Thanks for your interest in WebView! What version are you referring to? I think we might have something like that in older versions, but in the current code onPageFinished is always posted. You can check the latest version of AwWebContentsObserver here: https://code.google.com/p/chromium/codesearch#chromium/src/android_webview/java/src/org/chromium/android_webview/AwWebContentsObserver.java

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