Check if url is cached webview android

问题:

I use webview to load html pages and urls.

I want to load url only if internet is available or if the url content is cached by the web view.

How can I check if a url is cached without having to create my own cache on some external path.

   WebSettings ws = wv.getSettings();                                                                             
   ws.setJavaScriptEnabled(true);                                                                                 
   ws.setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);                                                          
     wv.setOnTouchListener(this);                                                                                 
   wv.setWebViewClient(new WebViewClient() {                                                                      
       @Override                                                                                                  
       public boolean shouldOverrideUrlLoading(WebView view, String url) {                                        
           if (!url.contains("http")) {                                                                           
               view.loadUrl(url);                                                                                 
           } else {                                                                                               
               if (Utils.isConnectingToInternet(thisActivity)) {                                                  
                   view.loadUrl(url);                                                                             

               }                                                                                                  
           }                                                                                                      
           view.loadUrl(url);                                                                                     
           return false;                                                                                          
       } 

I have referred to :

WebView Cache Data Directory?

Check if file already exists in webview cache android

How to move webView cache to SD?

Android webview check if page is in cache

回答1:

Set webview cache mode LOAD_CACHE_ELSE_NETWORK.

Override WebViewClient methods :

@SuppressWarnings("deprecation")
        @Override
        public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
            if (view.getUrl().equals(failingUrl)){
                showInternetConnectionError();
            }
            super.onReceivedError(view, errorCode, description, failingUrl);
        }

        @TargetApi(android.os.Build.VERSION_CODES.M)
        @Override
        public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
            onReceivedError(view, error.getErrorCode(), error.getDescription().toString(), request.getUrl().toString());
        }

It will load webpage from server if internet connection available, otherwise load from cache. If webpage is not available in cache then it will display internet connection error.

回答2:

Try overriding onPageCommitVisible inside your webviewclient. When the url is not cached and network is not available, this callback will be called.

@Override
public void onPageCommitVisible(WebView view, String url) {
                super.onPageCommitVisible(view, url);
                if(!isNetworkAvailable){
                    //page not cached
                }
                Timber.d("Page cannot draw")
}

Check internet availablity

boolean isNetworkAvailable(){
      ConnectivityManager cm =
        (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);

      NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
      boolean isConnected = activeNetwork != null &&
                      activeNetwork.isConnectedOrConnecting();
      return isConnected;

}