fragment to activity Backstack returns blank view

Question

I had Created a Home activity which includes Tablayout and Navigation Drawer onclick with fragment. I had included fragmentTransaction.addToBackStack(null).commit(); with the fragment transaction code to go back to previous Activity.

My Desired requirement was From Activity with tablayout-->NavigationDrawer-->Fragment1--> On BackButtonPress-->MainActivity with tablayout.

But,Now i am able to move to Fragment1,and when return to MainActivity,the view becomes filled with white(if i use mainLayout.removeAllViews(); and if wont use mainLayout.removeAllViews(); ,then the fragment is overlapping with the MainActivity)

1.My mainactivty

2.fragment

3.when i return to mainactivty

Now i cant see tablayout in my MainActivity.

Can anyone please help me.

mainactivity_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".HomeActivity"
    android:id="@+id/mainlayout"
    tools:showIn="@layout/app_bar_home">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/rel">
        <RelativeLayout
            android:id="@+id/main_layout1"
            xmlns:android="http://schemas.android.com/apk/res/android"
            xmlns:tools="http://schemas.android.com/tools"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:context=".MainActivity">

            <android.support.design.widget.TabLayout
                android:id="@+id/tab_layout1"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="?attr/colorPrimary"
                android:elevation="6dp"
                android:minHeight="?attr/actionBarSize"
                android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"/>

            <android.support.v4.view.ViewPager
                android:id="@+id/pager1"
                android:layout_width="match_parent"
                android:layout_height="fill_parent"
                android:layout_below="@id/tab_layout1"/>

        </RelativeLayout>
    </RelativeLayout>



</RelativeLayout>

MainActivity.java

    import android.content.Intent;
    import android.net.Uri;
    import android.os.Bundle;
    import android.support.design.widget.NavigationView;
    import android.support.design.widget.TabLayout;
    import android.support.v4.app.FragmentManager;
    import android.support.v4.app.FragmentTransaction;
    import android.support.v4.view.GravityCompat;
    import android.support.v4.view.ViewPager;
    import android.support.v4.widget.DrawerLayout;
    import android.support.v7.app.ActionBarDrawerToggle;
    import android.support.v7.app.AppCompatActivity;
    import android.support.v7.widget.Toolbar;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.widget.RelativeLayout;

    import java.io.File;
    import java.util.ArrayList;


    public class HomeActivity extends AppCompatActivity
            implements NavigationView.OnNavigationItemSelectedListener {


        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_home);
            Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
            setSupportActionBar(toolbar);

            DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
            ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                    this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
            drawer.setDrawerListener(toggle);
            toggle.syncState();

            NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
            navigationView.setNavigationItemSelectedListener(this);

            TabLayout tabLayout1 = (TabLayout) findViewById(R.id.tab_layout1);
            tabLayout1.addTab(tabLayout1.newTab().setIcon(R.drawable.tab_ic_home));
            tabLayout1.addTab(tabLayout1.newTab().setIcon(R.drawable.tab_ic_map));
            tabLayout1.addTab(tabLayout1.newTab().setIcon(R.drawable.tab_ic_login));

            tabLayout1.setTabGravity(TabLayout.GRAVITY_FILL);

            final ViewPager viewPager1 = (ViewPager) findViewById(R.id.pager1);
            final PagerAdapter1 adapter = new PagerAdapter1
                    (getSupportFragmentManager(), tabLayout1.getTabCount());
            viewPager1.setAdapter(adapter);
            viewPager1.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout1));
            tabLayout1.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
                @Override
                public void onTabSelected(TabLayout.Tab tab) {
                    viewPager1.setCurrentItem(tab.getPosition());
                }

                @Override
                public void onTabUnselected(TabLayout.Tab tab) {

                }

                @Override
                public void onTabReselected(TabLayout.Tab tab) {

                }
            });
        }

        @Override
        public void onBackPressed() {
            DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
            if (drawer.isDrawerOpen(GravityCompat.START)) {
                drawer.closeDrawer(GravityCompat.START);
            } else {
                super.onBackPressed();
            }
        }

        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.home, menu);
            return true;
        }

        @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            // Handle action bar item clicks here. The action bar will
            // automatically handle clicks on the Home/Up button, so long
            // as you specify a parent activity in AndroidManifest.xml.
            int id = item.getItemId();

            //noinspection SimplifiableIfStatement
            if (id == R.id.action_settings) {
                return true;
            }

            return super.onOptionsItemSelected(item);
        }

        @SuppressWarnings("StatementWithEmptyBody")
        @Override
        public boolean onNavigationItemSelected(MenuItem item) {
            FragmentManager fragmentManager = getSupportFragmentManager();
            FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
            // Handle navigation view item clicks here.
            int id = item.getItemId();
            RelativeLayout mainLayout=(RelativeLayout)findViewById(R.id.main_content);
            if (id == R.id.nav_login) {
                LoginFragment fragment = new LoginFragment();
    //            mainLayout.removeAllViews();
                fragmentTransaction.replace(R.id.mainlayout, fragment);
                fragmentTransaction.addToBackStack(null).commit();
            } 

            DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
            drawer.closeDrawer(GravityCompat.START);
            return true;
        }
    }

Fragment.java

  import android.annotation.SuppressLint;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class ContactFragment extends Fragment implements OnMapReadyCallback {

    private GoogleMap mMap;
    Button call;

    public ContactFragment() {
        // Required empty public constructor
    }
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.activity_contact,container,false);

        call = (Button) v.findViewById(R.id.button5);
        call.setOnClickListener(new View.OnClickListener() {
            @SuppressLint("NewApi")
            @Override
            public void onClick(View v) {
                Intent i = new Intent(Intent.ACTION_DIAL);
                i.setData(Uri.parse("tel:7034409615"));
                startActivity(i);
            }
        });
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getChildFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
        return v;


    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        // Add a marker in Sydney and move the camera
        LatLng sydney = new LatLng(9.2700, 76.7800);
        mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Pathanamthitta"));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
    }
}

Answer 1

As I suggested in the comments, in order to figure out the problem with displaying of fragments you can try to view what kind of fragments are being added into back stack as follows
Log.d("FragmentList",getSupportFragmentManager().getFragments().toString(); You can put it inside onBackPressed() ,onNavigationItemSelected()

According to your feedback it was helpful for you and you figured out the problem.

Also there are some layout design issues: Your current approach is to adding fragment into relative layout. I believe it leads to some problems with view. The recommended approach is to add fragments into FrameLayout as described in docs Also you may want to move everything outside view used for fragments I have rewritten your layout following recommended guidelines in the docs. P.S I haven't tested how it displayed.. you may have to tweak some layout params.

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                    xmlns:app="http://schemas.android.com/apk/res-auto"
                    xmlns:tools="http://schemas.android.com/tools"
                  android:orientation="vertical"
                  android:layout_width="match_parent"
                  android:layout_height="match_parent">
        <!--
        Layout for fragments
        -->
        <FrameLayout
                   android:id="@+id/mainlayout"
                        android:layout_width="match_parent"
                        android:layout_height="match_parent"
                        android:paddingBottom="@dimen/activity_vertical_margin"
                        app:layout_behavior="@string/appbar_scrolling_view_behavior"
                        tools:showIn="@layout/app_bar_home">

        </RelativeLayout>
        <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:id="@+id/rel">
            <RelativeLayout
                    android:id="@+id/main_layout1"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent">

                <android.support.design.widget.TabLayout
                        android:id="@+id/tab_layout1"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:background="?attr/colorPrimary"
                        android:elevation="6dp"
                        android:minHeight="?attr/actionBarSize"
                        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" android:orientation="horizontal"/>

                <android.support.v4.view.ViewPager
                        android:id="@+id/pager1"
                        android:layout_width="match_parent"
                        android:layout_height="fill_parent"
                        android:layout_below="@id/tab_layout1"/>

            </RelativeLayout>
        </RelativeLayout>
    </LinearLayout>

Also You defined multiple activities in your layout like tools:context=".MainActivity" and tools:context=".HomeActivity" I guess it's just unedited copy paste, but may lead some issues as well.

Hope you find it useful :)

Answer 2

In your MainActivity.java add this:

protected OnBackPressedListener onBackPressedListener;

public interface OnBackPressedListener {
    void doBack();
}

public void setOnBackPressedListener(OnBackPressedListener onBackPressedListener) {
    this.onBackPressedListener = onBackPressedListener;
}

@Override
public void onBackPressed() {
    if (onBackPressedListener != null)
        onBackPressedListener.doBack();
    else
        super.onBackPressed();
}

Than in Fragment.java implements class like this:

implements MainActivity.OnBackPressedListener

And implements method:

@Override
public void doBack() {
    Intent yourMainActivity = new Intent(getActivity(), MainActivity.class);
    startActivity(yourMainActivity);
}