Adding an app bar to a bottom navigation activity - android-studio

Question

I want to add an app bar to my app which has a bottom navigation bar. I followed the android developer's help and here is what I made in my activity:
public class BetsActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_bets);
BottomNavigationView bottomNavigationView = (BottomNavigationView)
findViewById(R.id.navigation);
bottomNavigationView.setOnNavigationItemSelectedListener
(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
Fragment selectedFragment = null;
switch (item.getItemId()) {
case R.id.navigation_p1:
selectedFragment = p1.newInstance();
Toolbar myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
break;
case R.id.navigation_p2:
selectedFragment = p2.newInstance();
myToolbar = (Toolbar) findViewById(R.id.my_toolbar);
setSupportActionBar(myToolbar);
break;
}
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_layout, selectedFragment);
transaction.commit();
return true;
}
});
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_layout, p1.newInstance());
transaction.commit();
}
Activity's layout:
<RelativeLayout
android:id="#+id/activity_main"
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"
tools:context="com.example.carbet.BetsActivity">
<FrameLayout
android:id="#+id/frame_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="#+id/navigation"
android:animateLayoutChanges="true">
</FrameLayout>
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:background="#color/colorPrimary"
app:itemTextColor="#android:color/white"
app:itemIconTint="#android:color/white"
app:menu="#menu/navigation" />
<android.support.v7.widget.Toolbar
android:id="#+id/my_toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:elevation="4dp"
android:theme="#style/ThemeOverlay.AppCompat.ActionBar"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"/>
</RelativeLayout>
And here is my app manifest:
<application
android:allowBackup="true"
android:icon="#mipmap/logo_car_bet"
android:label="#string/app_name"
android:roundIcon="#mipmap/logo_car_bet"
android:supportsRtl="true"
android:theme="#style/AppTheme.NoActionBar">
<meta-data
android:name="com.google.firebase.messaging.default_notification_icon"
android:resource="#mipmap/logo_car_bet" />
<meta-data
android:name="com.google.firebase.messaging.default_notification_color"
android:resource="#color/colorAccent" />
<activity
android:name=".MainActivity"
android:label="Car Bet"
android:theme="#style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".BetsActivity"
android:label="#string/title_activity_bets"
android:parentActivityName=".MainActivity"/>
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value=".MainActivity" />
</application>
I use fragments for the bottom nav bar but I don't do anything in their files.
When I launch it, first it shows a green bar, but without any title nor overflow menu. When I go to the other fragment, title appear but not the menu.
Please tell me which error(s) I made.

Answer 1

Add an AppBarLayout with ToolBar within in the xml
and in Java code, Add this after setContentView
Toolbar toolbar=findViewById(R.id.your_toolbar_id)
setSupportActionBar(toolbar);
and then inflate your Menu.