WebView cache doesn't work

Question

I'm trying to implement a cache for my webView loaded in one of my activity in my app. But I can't load my webview when I turn off my current wifi network.

My webView:

        progDialog = ProgressDialog.show(activity, "Loading", "Please wait...", true);
        progDialog.setCancelable(false);

        webView = (WebView) findViewById(R.id.my_web_view);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.getSettings().setAppCacheEnabled(true);
        webView.getSettings().setAppCachePath(getApplicationContext().getCacheDir().getAbsolutePath());
        webView.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                progDialog.show();

                if(isNetworkAvailable()){
                    view.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT);
                    view.loadUrl(url);
                }
                else{
                    view.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ONLY/*LOAD_CACHE_ELSE_NETWORK*/);
                    view.loadUrl(url);
                }

                return true;
            }

            @Override
            public void onPageFinished(WebView view, final String url) {
                progDialog.dismiss();
            }
        });
        webView.loadUrl("http://www.google.com/");

I tried to use this method to be able to know if my webView content was saved in cache (don't sure if it's very correct, just a test):

private void isCacheFileCreated(){
        String uri = "http://www.google.com/";
        String hashCode = String.format("%08x", uri.hashCode());
        File cacheFile = new File(new File(getCacheDir(), "webviewCache"), hashCode);

        if (cacheFile.exists()){
            // cache ok
        } else {
            // no cache
        }
    }

But when my network is off, file.exist() is always false.

My basic flow is: start my app > go to my activity with the webView and show the url content > turn off wifi > go back into my app > go back into the webview activity > and here I got an error message "Webpage not available".

Permissions in Manifest:

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>

isNetworkAvailable() method:

private boolean isNetworkAvailable() {
        ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo();
        return activeNetworkInfo != null && activeNetworkInfo.isConnected();
    }

Answer 1

Google sets cache-control:no-cache header, so its content is not cached by WebView. Try using a server where you can control the responses.

A few other notes:

• AppCache is not a general web cache, your web app must explicitly use it (see the docs); thus turning it on would not help;

• doing loadUrl from inside shouldOverrideUrlLoading is not necessary (and can sometimes lead to surprising results), you can just return false instead;

• not sure why you are assuming that web cache uses the particular scheme for naming files -- it's an implementation detail.