Patrón de navegación usando BottomNavigationView

readme.md

Sistema de navegación usando BottomNavigationView

Primer paso

Añadir menus menu/navigation.xml Crear layouts del principal activity_main.xmly de cada vista derivar de fragment_view.xml.xml

Segundo paso

Definición de las vistas relacionando con sus fragments define_fragment.java

Tercer paso

Implementar sistema de carga de fragments y definir la navegación MainActivity.java y cargar fragments con openfragment(contenedor,fragment)

Mantener los Fragments en memoria

Si queremos que los fragments esten en memoria y siempre que volvemos a el, este como lo dejamos.

  private void openFragment(int frameContainer, Fragment newFragment) {

  String loadFragmentName = newFragment.getClass().getName();
  FragmentManager fm = getSupportFragmentManager();
  FragmentTransaction ft = fm.beginTransaction();

  //ft.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out);

  Fragment currentFragment = getSupportFragmentManager().findFragmentById(frameContainer);

  if (currentFragment == null) {
      Log.d(TAG, "openFragment: ADD" + loadFragmentName + " in stack");
      ft.add(frameContainer, newFragment, loadFragmentName);
      ft.commit();
      oldFragmentTAG = loadFragmentName;
  } else {

      if (!oldFragmentTAG.equalsIgnoreCase(loadFragmentName)) {
          Log.d(TAG, "openFragment: REPLACE" + loadFragmentName + " in stack");

          if (fm.findFragmentByTag(loadFragmentName) == null) {
              ft.add(frameContainer, newFragment, loadFragmentName);
              ft.commit();
          }

          showHideFragment(fm.findFragmentByTag(oldFragmentTAG));
          showHideFragment(fm.findFragmentByTag(loadFragmentName));

          //ft.addToBackStack(newFragment.getClass().getName());
          oldFragmentTAG = loadFragmentName;
      } else {
          Log.w(TAG, "openFragment: NO REPLACE");
      }

  }

}

activity_main.xml

<?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:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.webserveis.app.imagestudio.MainActivity">

    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="@android:color/holo_orange_light"/>

    <android.support.design.widget.BottomNavigationView
        android:id="@+id/navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:background="?android:attr/windowBackground"
        app:menu="@menu/navigation" />

</LinearLayout>

define_fragment.java

public class FirstFragment extends Fragment {
    private static final String TAG = FirstFragment.class.getSimpleName();

    private final String SAVED_BUNDLE_TAG = "saved_bundle";
    private boolean isChecked;

    public static FirstFragment newInstance() {
        FirstFragment fragment = new FirstFragment();
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        Log.i(TAG, "onSaveInstanceState: ");
        outState.putBoolean(SAVED_BUNDLE_TAG, isChecked);
        super.onViewStateRestored(outState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        Log.i(TAG, "onCreateView: FirstFragment");
        View view = inflater.inflate(R.layout.fragment_one, container, false);
        final CheckBox cbCheckBox = (CheckBox) view.findViewById(R.id.checkBox);

        if (savedInstanceState != null) {
            Log.d(TAG, "savedInstanceState: true");
            isChecked = savedInstanceState.getBoolean(SAVED_BUNDLE_TAG, false);
            cbCheckBox.setChecked(isChecked);
        }
        cbCheckBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
                Log.d(TAG, "onCheckedChanged: " + b);
                isChecked = b;
            }
        });

        return view;
    }


}

fragment_view.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Primer fragmento" />

    <CheckBox
        android:id="@+id/checkBox"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="CheckBox" />

</LinearLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity
        implements BottomNavigationView.OnNavigationItemSelectedListener {

    private static final String TAG = MainActivity.class.getSimpleName();
    private Fragment selectedFragment = null;

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

        //mTextMessage = (TextView) findViewById(R.id.message);
        BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
        navigation.setOnNavigationItemSelectedListener(this);

        if (savedInstanceState == null) {
            onNavigationItemSelected(navigation.getMenu().findItem(R.id.navigation_home));
        } else {
            Log.w(TAG, "savedInstanceState is not null ");
            selectedFragment = getSupportFragmentManager().getFragment(savedInstanceState, "main_content");
        }

    }

    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {

        switch (item.getItemId()) {
            case R.id.navigation_home:
                selectedFragment = FirstFragment.newInstance();
                break;
            case R.id.navigation_dashboard:
                selectedFragment = SecondFragment.newInstance();
                break;
            case R.id.navigation_notifications:
                selectedFragment = ThirdFragment.newInstance();
                break;
        }
        if (selectedFragment != null) {
            Log.d(TAG, "onNavigationItemSelected: ");
            openFragment(R.id.content_frame, selectedFragment);
            return true;
        } else return false;

    }

}

navigation.xml

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">

    <item
        android:id="@+id/navigation_home"
        android:icon="@drawable/ic_home_black_24dp"
        android:title="@string/title_home" />

    <item
        android:id="@+id/navigation_dashboard"
        android:icon="@drawable/ic_dashboard_black_24dp"
        android:title="@string/title_dashboard" />

    <item
        android:id="@+id/navigation_notifications"
        android:icon="@drawable/ic_notifications_black_24dp"
        android:title="@string/title_notifications" />

</menu>

openfragment.java

    private void openFragment(int frameContainer, Fragment newFragment) {

        String loadFragmentName = newFragment.getClass().getName();
        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction ft = fm.beginTransaction();

        Fragment currentFragment = getSupportFragmentManager().findFragmentById(frameContainer);

        if (currentFragment == null) {
            Log.d(TAG, "openFragment: ADD" + loadFragmentName + " in stack");
            ft.add(frameContainer, newFragment);
        } else {

            if (!currentFragment.getClass().getName().equalsIgnoreCase(loadFragmentName)) {
                Log.d(TAG, "openFragment: REPLACE" + loadFragmentName + " in stack");

                ft.replace(frameContainer, newFragment);
                //ft.addToBackStack(newFragment.getClass().getName());

            } else {
                Log.w(TAG, "openFragment: NO REPLACE");
            }

        }

        ft.commit();

    }

showHideFragment.java

public void showHideFragment(final Fragment fragment) {

    if (fragment != null) {

        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction ft = fm.beginTransaction();

        ft.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out);

        if (fragment.isHidden()) {
            ft.show(fragment);
        } else {
            ft.hide(fragment);
        }

        ft.commit();
    }
}