Menus - Option Menu (Menu and App Bar)

It is the basic structure of menu item for an activity.

To create a menu for an activity, we need to create a folder in res with name menu and create and menu as

main_menu.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"   xmlns:app="http://schemas.android.com/apk/res-auto">   <item       android:id="@+id/share"       android:icon="@android:drawable/ic_menu_share"       android:title="Share"       app:showAsAction="always" />   <item       android:id="@+id/wishlist"       android:icon="@android:drawable/star_on"       android:title="Wishlist"       app:showAsAction="ifRoom" />   <item       android:id="@+id/view"       android:icon="@android:drawable/ic_menu_view"       android:title="View"       app:showAsAction="withText" />   <item       android:id="@+id/save"       android:icon="@android:drawable/ic_menu_save"       android:title="Save"       app:showAsAction="withText" /> </menu>

activity_main.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:gravity="center">   <TextView       android:id="@+id/message"       android:layout_width="wrap_content"       android:layout_height="wrap_content"       android:textSize="25sp"       android:textColor="#000000"       android:text="@string/app_name" /> </LinearLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity {   TextView message;   @Override   protected void onCreate(Bundle savedInstanceState) {       super.onCreate(savedInstanceState);       setContentView(R.layout.activity_main);       message=findViewById(R.id.message);   }   @Override   public boolean onCreateOptionsMenu(Menu menu) {       getMenuInflater().inflate(R.menu.main_menu, menu);       return true;   }   @Override   public boolean onOptionsItemSelected(MenuItem item) {       int id = item.getItemId();       switch (id){           case R.id.share:               message.setText("Share it.");               break;           case R.id.wishlist:               message.setText("Add to Wishlist.");               Toast.makeText(MainActivity.this,"Added",Toast.LENGTH_LONG).show();               break;           case R.id.view:               message.setText("View it");               break;           case R.id.save:               message.setText("Save");               break;       }       return super.onOptionsItemSelected(item);   } }