WebView reloading when Fragment in ViewPager is retained form BackStack

Vishal Vijay picture Vishal Vijay · Apr 29, 2013 · Viewed 8k times · Source

Here is a code for a basic Fragment which contains a WebView.
WebFragment.java

public class WebFragment extends Fragment {
String TAG = "WebFragment";
private WebView webView;
private String currentUrl = "http://www.google.com";

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    return inflater.inflate(R.layout.webview_layout, null);
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);
    webView = (WebView) getView().findViewById(R.id.helloWebview);
    initWebView();
    webView.loadUrl(currentUrl);
}

@SuppressLint("SetJavaScriptEnabled")
private void initWebView() {
    webView.getSettings().setJavaScriptEnabled(true);
    webView.addJavascriptInterface(new JavaScriptInterface(), "HTMLOUT");
    webView.setWebViewClient(new WebViewClient() {
        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            Log.e(TAG, "Loding...");
            super.onPageStarted(view, url, favicon);
        }
    });
}

class JavaScriptInterface {
    public void showHTML(String html) {
    }
}
}

I have 2 more basic fragments also(which doesn't have WebView). Then I put all these 3 Fragments in ViewPager(WebFragment, Fragment1 and Fragment2respectively) using FragmentAdapter. And I added android:configChanges="orientation|screenSize" in AndroidManifest.xml(So WebView will not realod on configration change).
Now my problem is, While running app I changed the 1st page (WebFragmet) of ViewPager to 2nd page(Fragment1) and again I came back to 1st page. So no problem WebFragment is as it is.

Now again I changed the ViewPager like this WebFragment-->Fragment1-->Fragment2 and came back to 1st page by reversing the direction of above action. But at that time I saw the WebView in WebFragment is reloading.

And one more problem, whenever the WebView started loading I can see 2 log entry like.

WebFragment Loading...
WebFragment Loading...

So my question is :
1) How can I prevent WebView reloading when the WebFragment is retained from BackStack?
2) Why here WebView loading twice?

Just see this question and help me(Prevent WebView reloads in FragmentPagerAdapter?).

Answer

Chirag Shah picture Chirag Shah · May 9, 2013

In your main activity where you have defined viewpager

after the declaration of viewpager like this line : ViewPager viewpager = (ViewPager) findViewById(R.id.pager);

add this line :

viewpager.setOffscreenPageLimit(2);

This will prevent your fragment from recreated upto swipe of two screens,so when you will return from 3rd page to 1st page in viewpager,your webview will not reload.