Preliminary understanding of menu items

Mainactivity.class

public class Mainactivity extends Appcompatactivity {private TextView TextView;        @Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);        Setcontentview (R.layout.activity_main);    TextView = (TextView) Findviewbyid (r.id.txt); } @Override Public boolean Oncreateoptionsmenu (Menu menu) {//Inflate the menu, this adds items to the Actio        n Bar if it is present.        Add a menu//Getmenuinflater () by adding the XML method statically. Inflate (R.menu.menu_main, menu); Method Two, adding the code dynamically add the menu item MenuItem item = menu.add (1, 100, 1, "Zhao 1");        Parameters (GroupID, ItemID, order, title) Item.settitle ("AAA");        Menu.add (1,101,1, "Zhao 2");        Menu.add (1,102,1, "Zhao 3");                Menu.add (1,5,1, "Zhao 4");    return true; } @Override public boolean onoptionsitemselected (MenuItem Item) {//Handle Action Bar item clicks here. The action bar would//automatically handle clicks on the Home/up button, so Long/As you specify a the parent activity in Androidmanifest.xml.        int id = item.getitemid (); Noinspection simplifiableifstatement switch (ID) {case 100:{Intent Intent = new Intent                (Mainactivity.this,second_demo.class); Item.setintent (Intent);                Jump to other activity Textview.settext ("clicked" + ID);            Break                } Case 101:{Textview.settext ("clicked" + ID);            Break                } Case 102:{Textview.settext ("clicked" + ID);            Break                } Case 5:{Textview.settext ("clicked" + ID);            Break    }} return super.onoptionsitemselected (item); }}

　　

Preliminary understanding of menu items