子菜单，含有菜单项的菜单
添加方式：静态xml/动态添加
menu/main.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

    <item
        android:showAsAction="never"
        android:title="文件">
        <menu>
            <item
                android:id="@+id/new_file"
                android:showAsAction="never"
                android:title="新建"/>
            <item
                android:id="@+id/open_file"
                android:showAsAction="never"
                android:title="打开"/>
            <item
                android:id="@+id/save_file"
                android:showAsAction="never"
                android:title="保存"/>
        </menu>
    </item>
     <item
        android:showAsAction="never"
        android:title="编辑">
        <menu>
            <item
                android:id="@+id/c_edit"
                android:showAsAction="never"
                android:title="复制"/>
            <item
                android:id="@+id/v_edit"
                android:showAsAction="never"
                android:title="粘贴"/>
            <item
                android:id="@+id/x_edit"
                android:showAsAction="never"
                android:title="剪切"/>
        </menu>
    </item>
</menu>

MainActivity.java

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.SubMenu;
import android.widget.Toast;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        // getMenuInflater().inflate(R.menu.main, menu);
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main, menu);
//      SubMenu file = menu.addSubMenu("文件");
//      SubMenu edit = menu.addSubMenu("编辑");
//      file.add(1, 1, 1, "新建");
//      file.add(1, 2, 1, "打开");
//      file.add(1, 3, 1, "保存");
//      file.setHeaderTitle("文件操作");//子菜单标题
//      file.setHeaderIcon(R.drawable.ic_launcher);//子菜单图标
//      edit.add(2, 1, 1, "复制");
//      edit.add(2, 2, 1, "粘贴");
//      edit.add(2, 3, 1, "剪切");
//      edit.setHeaderTitle("编辑操作");
//      edit.setHeaderIcon(R.drawable.ic_launcher);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // TODO Auto-generated method stub
        switch (item.getItemId()) {
        case R.id.new_file:
            Toast.makeText(this, "点击了新建",Toast.LENGTH_SHORT).show();
            break;
        case R.id.open_file:
            Toast.makeText(this, "点击了打开",Toast.LENGTH_SHORT).show();
            break;
        case R.id.save_file:
            Toast.makeText(this, "点击了保存",Toast.LENGTH_SHORT).show();
            break;
        case R.id.c_edit:
            Toast.makeText(this, "点击了复制",Toast.LENGTH_SHORT).show();
            break;
        case R.id.v_edit:
            Toast.makeText(this, "点击了粘贴",Toast.LENGTH_SHORT).show();
            break;
        case R.id.x_edit:
            Toast.makeText(this, "点击了剪切",Toast.LENGTH_SHORT).show();
            break;
        }
        return super.onOptionsItemSelected(item);
    }
}

效果演示：

sub.gif