How to keep the contents of a WebView inside a Fragment?

Question

Java

There are several fragments (playing the role of tabs) inside each WebView. When switching to another tab (fragments), the previous one is reset and loads the start page. tell me how to do that when switching WebView, the state of the page would be saved until the application is completely closed?

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;
    }
 
}