25 Nov 2008, This tutorial has been superceded by Building a Menu for your Android (V1.0 R1) App.

19 Aug 2008, Note: Due to changes to the Android SDK, the code in this example does not work in 0.9 beta.

The menu builder class provides a way to build a simple menu, similar to the one below, in Android.

Menu built with the menu builder class.

To do anything useful with the menu, you need to specify what to do when an item is selected. A class that implements the MenuItem.OnClickListener interface is required to perform these actions. Here is an example of a listener that popups a dialog with the selection:

1   public class AndroidMenuButton extends Activity
2   {
3       private View menuInstance = null;
4  
5       private class ReactToClick
            implements Menu.OnClickListener
6       {
7           public ReactToClick()
8           {
9               // Empty constructor. Do nothing.
10          }
11          
12          /**
13           * React to an item being clicked.
14           */
15          public boolean onClick(Item item) 
16          {
17              // Display a that "echoes" the item that was
                // selected.
18              AlertDialog.Builder dialogBuilder = new 
19                  AlertDialog.Builder(AndroidMenuButton.this);
20              
21              dialogBuilder.setMessage(" You selected " +
22                      item.getTitle());
23              dialogBuilder.setCancelable(true);
24              dialogBuilder.create().show();
25  
26              // Click has been processed, so consume it.
27              return true;
28          }
29      }
30  

A layout can be setup to place the view on. For this example, I’ve set up a vertical linear view using XML and I grab the layout with the findViewById method:

31      /** 
32       * Called when the activity is first created. 
33       */
34      @Override
35      public void onCreate(Bundle icicle) 
36      {
37          super.onCreate(icicle);
38          setContentView(R.layout.capbutton);
39  
40          // Grab the view’s layout.
41          LinearLayout backView = (LinearLayout) 
42              findViewById(R.id.backgroundView);
43          

Next, create an instance of a MenuBuilder object and use the add method to place the menu items. Images for the menu items should be placed as a resource in res/drawables.

44          // Create the menu builder.
45          MenuBuilder builder = new MenuBuilder(this);
46          builder.setHeader("Menu Demo");
47          Item newItem = null;
48          ReactToClick action = new ReactToClick();
49          
50          // Tell the menu builder how to build the menu.
51          newItem = builder.add(0, 1, "Photos",
                R.drawable.item1);

The class, R, should be automatically be generated for you by the Android Eclipse plugin. R should contain references to all of your resources. The add method will return an Item object, to which you add your listeners to.

52          newItem.setClickListener(action);
53          newItem = builder.add(0, 2, "Painting",
                R.drawable.item2);
54          newItem.setClickListener(action);
55          newItem = builder.add(0, 3, "Science",
                R.drawable.item3);
56          newItem.setClickListener(action);
57          

Once all of the menu items have been added, the menu view can be constructed by the viewer and added to your own view.

58          // Get the menu instance and add it the view.
59          menuInstance = builder.getMenuView
60              (MenuBuilder.TYPE_ICON, backView, true);
61          menuInstance.setBackgroundColor(Color.WHITE);
62  
63          backView.addView(menuInstance);
64      }
65  }

It is also possible to have Android create the menu in different formats, such as the icon view (pictured in the first screenshot) or the context menu (pictured in the screenshot below).

Example of a context type menu.

The type of menu displayed is controlled by the first parameter to the MenuBuilder’s getMenuView method. The other two types of menus that have not been mentioned are the expanded menu and submenus. The MenuBuilder documentation details which constants the parameter needs to be set to in order to obtain the different types of menus (see the Constants section).