Android menu usage

1. Normal menu

Let's take a look at how to implement the simplest menu.

Override the oncreateoptionsmenu (menu) method in the main activity.

Code

 @ Override
Public Boolean oncreateoptionsmenu (menu ){
// Todo auto-generated method stub
Menu. Add (0, 1, 1, "apple ");
Menu. Add (0, 2, 2, "banana ");
Return super. oncreateoptionsmenu (menu );
}

In this way, two menu options are available. To add a click event, override the onoptionsitemselected (menuitem item) method.

Code

 @ Override
Public Boolean onoptionsitemselected (menuitem item ){
// Todo auto-generated method stub
If (item. getitemid () = 1 ){
Toast T = toast. maketext (this, "you selected Apple", Toast. length_short );
T. Show ();
}
Else if (item. getitemid () = 2 ){
Toast T = toast. maketext (this, "you selected bananas", Toast. length_short );
T. Show ();
}
Return true;
}

 

2. Submenu

Submenu creation is also simple. Add a few sentences to the oncreateoptionsmenu (menu) method of the first code, as follows:

Code

 @ Override
Public Boolean oncreateoptionsmenu (menu ){
// Todo auto-generated method stub
Menu. Add (0, 1, 1, "apple ");
Menu. Add (0, 2, 2, "banana ");
Submenu = menu. addsubmenu (1,100,100, "Peach ");
Submenu. Add (2,101,101, "Peach ");
Submenu. Add (2,102,102, "Peach ");
Return true;
}

After you click "Peach", the sub menu will appear. There are two sub options: "big peach" and "little peach ".

3. Context Menu

It is similar to the shortcut menu on the computer that pops up after a view is long pressed.

First, define several buttons in Main. xml. Then override the oncreatecontextmenu (contextmenu menu, view V, contextmenuinfo menuinfo) method. The Code is as follows:

First, you must register the following code in the oncreate method:

Code

 @Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        b1 = (Button) findViewById(R.id.b1);
        b2 = (Button) findViewById(R.id.b2);
        registerForContextMenu(b1);
        registerForContextMenu(b2);
    }

 

Code

 @ Override
Public void oncreatecontextmenu (contextmenu menu, view V,
Contextmenuinfo menuinfo ){
// Todo auto-generated method stub
If (V = b1 ){
Menu. setheadertitle ("this is 1 ");
Menu. Add (200,200,200, "context menu 1 ");
Menu. Add (200,201,201, "context menu 2 ");
}
Else if (V = b2 ){
Menu. setheadertitle ("this is 2 ");
Menu. Add (300,300,300, "C 1 ");
Menu. Add (300,301,301, "C 2 ");
}
Super. oncreatecontextmenu (menu, V, menuinfo );
}

4. Dynamic menu

Dynamic menus are different based on different interfaces. The following code implements this function: when the value of a textview on the main interface is "M" and "N", different menus are displayed.

Code

 @ Override
Public Boolean onprepareoptionsmenu (menu ){
// Todo auto-generated method stub
String currenttext = tv1.gettext (). tostring ();
If ("M". Equals (currenttext )){
Menu. Clear (); // clear the menu first
Menuitem item = menu. Add (0,400,401, "to N"); // you can click this menu item to change the value of TV1 so that it can be tested.
Item. seticon (Android. R. drawable. alert_dark_frame); // the built-in Android icon
}
If ("N". Equals (currenttext )){
Menu. Clear (); // clear the menu first
Menuitem item = menu. Add (0,401,402, "to M"); // you can click this menu item to change the value of TV1 so that it can be tested.
Item. seticon (Android. R. drawable. alert_light_frame );
}
Menu. Add (0,402,403, "now is" + currenttext); // There are currently two menu items
Return super. onprepareoptionsmenu (menu );
}

　　

5. Create a menu using an XML file

Previously, menus were created using code, and menus can be easily created using xml configuration files.

To create a folder named menu under the Res/directory, create an XML file named menu_xml_file.xml. The Code is as follows:

Code

 <?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<group android:id="@+id/grout_main">
<item android:id="@+id/menu_1"
                android:title="This 1"/>
<item android:id="@+id/menu_2" 
            android:title="This 2" /> 
</group>
</menu>

Override the oncreateoptionsmenu (menu) method in the activity. The Code is as follows:

Code

 @Override
public boolean onCreateOptionsMenu(Menu menu) {
// TODO Auto-generated method stub
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu_xml_file, menu);
return true;
    }

Others are the same as creating menus in the activity.