caching - Android Webview - Completely Clear the Cache

Question

I have a WebView in one of my Activities, and when it loads a webpage, the page gathers some background data from Facebook.

What I'm seeing though, is the page displayed in the application is the same on each time the app is opened and refreshed.

I've tried setting the WebView not to use cache and clear the cache and history of the WebView.

I've also followed the suggestion here: How to empty cache for WebView?

But none of this works, does anyone have any ideas of I can overcome this problem because it is a vital part of my application.

    mWebView.setWebChromeClient(new WebChromeClient()
    {
           public void onProgressChanged(WebView view, int progress)
           {
               if(progress >= 100)
               {
                   mProgressBar.setVisibility(ProgressBar.INVISIBLE);
               }
               else
               {
                   mProgressBar.setVisibility(ProgressBar.VISIBLE);
               }
           }
    });
    mWebView.setWebViewClient(new SignInFBWebViewClient(mUIHandler));
    mWebView.getSettings().setJavaScriptEnabled(true);
    mWebView.clearHistory();
    mWebView.clearFormData();
    mWebView.clearCache(true);

    WebSettings webSettings = mWebView.getSettings();
    webSettings.setCacheMode(WebSettings.LOAD_NO_CACHE);

    Time time = new Time();
    time.setToNow();

    mWebView.loadUrl(mSocialProxy.getSignInURL()+"?time="+time.format("%Y%m%d%H%M%S"));

So I implemented the first suggestion (Although changed the code to be recursive)

private void clearApplicationCache() {
    File dir = getCacheDir();

    if (dir != null && dir.isDirectory()) {
        try {
            ArrayList<File> stack = new ArrayList<File>();

            // Initialise the list
            File[] children = dir.listFiles();
            for (File child : children) {
                stack.add(child);
            }

            while (stack.size() > 0) {
                Log.v(TAG, LOG_START + "Clearing the stack - " + stack.size());
                File f = stack.get(stack.size() - 1);
                if (f.isDirectory() == true) {
                    boolean empty = f.delete();

                    if (empty == false) {
                        File[] files = f.listFiles();
                        if (files.length != 0) {
                            for (File tmp : files) {
                                stack.add(tmp);
                            }
                        }
                    } else {
                        stack.remove(stack.size() - 1);
                    }
                } else {
                    f.delete();
                    stack.remove(stack.size() - 1);
                }
            }
        } catch (Exception e) {
            Log.e(TAG, LOG_START + "Failed to clean the cache");
        }
    }
}

However this still hasn't changed what the page is displaying. On my desktop browser I am getting different html code to the web page produced in the WebView so I know the WebView must be caching somewhere.

On the IRC channel I was pointed to a fix to remove caching from a URL Connection but can't see how to apply it to a WebView yet.

http://www.androidsnippets.org/snippets/45/

If I delete my application and re-install it, I can get the webpage back up to date, i.e. a non-cached version. The main problem is the changes are made to links in the webpage, so the front end of the webpage is completely unchanged.

Answer 1

I found an even elegant and simple solution to clearing cache

WebView obj;
obj.clearCache(true);

http://developer.android.com/reference/android/webkit/WebView.html#clearCache%28boolean%29

I have been trying to figure out the way to clear the cache, but all we could do from the above mentioned methods was remove the local files, but it never clean the RAM.

The API clearCache, frees up the RAM used by the webview and hence mandates that the webpage be loaded again.