How to display Fragment in a tab Activity

Question

I'm facing a quite frustrating bug in my app, let me explain: I have a MainActivity with an appBar containing 3 tabs and each tab displays a Fragment. The problem comes when I try to lunch another Fragment and make it replace all the screen. The new Fragment is displayed on the replaced one and the two are visible.

Here is my code:

The MainActivity:

public class MainActivity extends AppCompatActivity {

public static Model model;
public static Controller controller;

private SectionsPagerAdapter mSectionsPagerAdapter;
private ViewPager mViewPager;

private static final int PERMISSION_GALERIE = 10;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main_layout);

    this.model = new Model();
    this.controller = new Controller(model,this);

    final Toolbar toolbar = (Toolbar)findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
    mViewPager = (ViewPager)findViewById(R.id.container);
    mViewPager.setAdapter(mSectionsPagerAdapter);

    TabLayout tabLayout = (TabLayout)findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(mViewPager);
}

@Override
public boolean onCreateOptionsMenu(android.view.Menu menu) {
    getMenuInflater().inflate(R.menu.settings,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.db_setting) {
        getFragmentManager().beginTransaction().replace(R.id.mainLayout, new DBSettingFragment()).commit();
    }

    return super.onOptionsItemSelected(item);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);



}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    if(requestCode==PERMISSION_GALERIE){
        if(grantResults.length==1 && grantResults[0]== PackageManager.PERMISSION_GRANTED){
            Snackbar.make(getCurrentFocus(),"Permission accordée",Snackbar.LENGTH_SHORT);
        }
    }
    else{
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }
}

public class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public android.support.v4.app.Fragment getItem(int position) {
        Fragment menusManagementFragment = new MenusManagementFragment();
        switch (position) {
            case 0:
                return menusManagementFragment;
            case 1:
                OrdersManagementFragment ordersManagementFragment = new OrdersManagementFragment();
                return ordersManagementFragment;
            case 2:
                DeliversManagementFragment deliversManagementFragment = new DeliversManagementFragment();
                return deliversManagementFragment;

            default: return menusManagementFragment;
        }

    }

    @Override
    public int getCount() {
        return 3;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return "Gestion des menus";
            case 1:
                return "Gestion des commandes";
            case 2:
                return "Gestiond des livreurs";
        }
        return null;
    }
}}

The main_layout:

<android.support.design.widget.CoordinatorLayout 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:id="@+id/mainLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">

<android.support.design.widget.AppBarLayout
    android:id="@+id/appbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingTop="16dp"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay">

    </android.support.v7.widget.Toolbar>

    <android.support.design.widget.TabLayout
        android:id="@+id/tabs"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</android.support.design.widget.AppBarLayout>

<android.support.v4.view.ViewPager
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

And in DeliversManagementFragment I do:

deliverStatsButton.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        getFragmentManager().beginTransaction().replace(R.id.mainLayout,new DeliverStatsFragment()).commit();
                    }
                });

If someone could help that would be kind. Thanks.

Answer 1

You don't need to replace a fragment like this

getFragmentManager().beginTransaction().replace(R.id.mainLayout,new DeliverStatsFragment()).commit();

you need to use viewpager.setCurrentItem() for changing the position

OR

make your DeliverStatsFragment background color as white and set clickable="true"