Webview没有缓存所有网址

Question

我可以在android中缓存某些网址的WebView内容，例如google.com。 只能缓存一些网址。在尝试离线显示某些网址内容时，它显示没有连接。

public class Main2Activity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);


        setContentView(R.layout.activity_main2);
        WebView browser = (WebView) findViewById(R.id.webView1);
        String weblink = url;

        if(isNetworkAvailable()) {
            Log.d("TRIAL","ONLINE");
            browser.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT);
            browser.loadUrl(weblink);
        } else {
            Log.d("TRIAL","OFFLINE");
            browser.getSettings().setCacheMode(WebSettings.LOAD_CACHE_ELSE_NETWORK);
            browser.loadUrl(weblink);
        }
}

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

}