Как сохранять содержимое WebView внутри фрагмента?

Question

[Максим]

есть несколько фрагментов(играют роль вкладок), внутри каждого WebView. При переключении на другую вкладку(фрагментов) предыдущая сбрасывается и грузит стартовую страницу. подскажите как сделать, что бы при переключении WebView сохранялось состояние страницы до полного закрытия приложения?

MainActivity:

public class MainActivity extends AppCompatActivity {
 
    /**
     * The {@link android.support.v4.view.PagerAdapter} that will provide
     * fragments for each of the sections. We use a
     * {@link FragmentPagerAdapter} derivative, which will keep every
     * loaded fragment in memory. If this becomes too memory intensive, it
     * may be best to switch to a
     * {@link android.support.v4.app.FragmentStatePagerAdapter}.
     */
    private SectionsPagerAdapter mSectionsPagerAdapter;
 
    /**
     * The {@link ViewPager} that will host the section contents.
     */
    private ViewPager mViewPager;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
 
 
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
 
        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
 
        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);
 
        TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(mViewPager);
    }
 
 
    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        private static final String ARG_SECTION_NUMBER = "section_number";
 
        public PlaceholderFragment() {
        }
 
        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }
 
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container, false);
            TextView textView = (TextView) rootView.findViewById(R.id.section_label);
            textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
            return rootView;
        }    }
 
    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {
 
        public SectionsPagerAdapter(FragmentManager fm) {
            super(fm);
        }
 
        @Override
        public Fragment getItem(int position) {
            switch (position){
                case 0:
                    Tab1 tab1 = new Tab1();
                    return tab1;
                case 1:
                    Tab2 tab2 = new Tab2();
                    return tab2;
                case 2:
                    Tab3 tab3 = new Tab3();
                    return tab3;
                case 3:
                    Tab4 tab4 = new Tab4();
                    return tab4;
                case 4:
                    Tab5 tab5 = new Tab5();
                    return tab5;
            }
            return null;
        }
 
        @Override
        public int getCount() {
            // Show 3 total pages.
            return 5;
        }
 
        @Override
        public CharSequence getPageTitle(int position) {
            switch (position) {
                case 0:
                    return "вкладка 1";
                case 1:
                    return "вкладка 2";
                case 2:
                    return "вкладка 3";
                case 3:
                    return "вкладка 4";
                case 4:
                    return "вкладка 5";
            }
            return null;
        }

fragment

package choowong.android.wastemanagement;
 
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.support.v4.app.Fragment;
import android.webkit.CookieManager;
import android.webkit.WebSettings;
import android.webkit.WebStorage;
import android.webkit.WebView;
import android.webkit.WebViewClient;
 
 
public class Tab1 extends Fragment {
 
    public static WebView mWebView;
 
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v=inflater.inflate(R.layout.tab1, container, false);
        mWebView = (WebView) v.findViewById(R.id.webViewT1);
        if (savedInstanceState == null)
        {
            mWebView.loadUrl("file:///android_asset/Maps/web/map.html");
        }
        mWebView.getSettings().setBuiltInZoomControls(true);
        mWebView.getSettings().setDisplayZoomControls(false);
        WebSettings webSettings = mWebView.getSettings();
        mWebView.setOnKeyListener(new View.OnKeyListener(){
 
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                if (keyCode == KeyEvent.KEYCODE_BACK
                        && event.getAction() == MotionEvent.ACTION_UP
                        && mWebView.canGoBack())
                {
                    mWebView.goBack();
                    return true;
                }
                return false;
            }
 
        });
        WebStorage.getInstance().deleteAllData();
 
        mWebView.getSettings().setDomStorageEnabled(true);
        mWebView.getSettings().setAllowFileAccess(true);
 
 
        // Enable Javascript
        webSettings.setJavaScriptEnabled(true);
 
        // Force links and redirects to open in the WebView instead of in a browser
        mWebView.setWebViewClient(new WebViewClient());
 
        return v;
    }
 
}