[android] How to set menu to Toolbar in Android

Although I agree with this answer, as it has fewer lines of code and that it works:

How to set menu to Toolbar in Android

My suggestion would be to always start any project using the Android Studio Wizard. In that code you will find some styles:-

<style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar" />

<style name="AppTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light" />

and usage is:

<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
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.design.widget.AppBarLayout> 

Due to no action bar theme declared in styles.xml, that is applied to the Main Activityin the AndroidManifest.xml, there are no exceptions, so you have to check it there.

<activity android:name=".MainActivity" android:screenOrientation="portrait"
        android:theme="@style/AppTheme.NoActionBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

1. The Toolbar is not an independent entity, it is always a child view in AppBarLayout that again is the child of CoordinatorLayout.
2. The code for creating a menu is the standard code since day one, that is repeated again and again in all the answers, particularly the marked one, but nobody realized what is the difference.

BOTH:

Toolbar toolbar = findViewById(R.id.toolbar); setSupportActionBar(toolbar);

AND:

How to set menu to Toolbar in Android

WILL WORK.

Happy Coding :-)