import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.SubMenu;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

  //  定義“字體大小”菜單項(xiàng)的標(biāo)示
  final int FONT_10 = 0X111;
  final int FONT_12 = 0X112;
  final int FONT_14 = 0X113;
  final int FONT_16 = 0X114;
  final int FONT_18 = 0X115;
  //  定義“普通菜單項(xiàng)”的標(biāo)示
  final int PLAIN_ITEM = 0x11b;
  //  定義“字體顏色”菜單項(xiàng)的標(biāo)示
  final int FONT_RED = 0X116;
  final int FONT_BLUE = 0X117;
  final int FONT_GREEN = 0X118;
  private EditText editText;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    editText = (EditText) findViewById(R.id.edit);


  }

  //當(dāng)用戶單擊menu鍵時(shí)觸發(fā)該方法
  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
//    向menu中添加“字體大小”的子菜單
    SubMenu fontMenu = menu.addSubMenu("字體大小");
//    設(shè)置菜單的圖標(biāo)
    fontMenu.setIcon(R.mipmap.ic_launcher);
//    設(shè)置菜單頭的圖標(biāo)
    fontMenu.setHeaderIcon(R.mipmap.ic_launcher_round);
//    設(shè)置菜單頭的標(biāo)題
    fontMenu.setHeaderTitle("選擇字體大小");
    fontMenu.add(0, FONT_10, 0, "10號字體");
    fontMenu.add(0, FONT_12, 0, "12號字體");
    fontMenu.add(0, FONT_14, 0, "14號字體");
    fontMenu.add(0, FONT_16, 0, "16號字體");
    fontMenu.add(0, FONT_18, 0, "18號字體");
//    向menu中添加“普通菜單項(xiàng)”
    menu.add(0, PLAIN_ITEM, Menu.NONE, "普通菜單項(xiàng)");
//    向menu中添加“字體顏色”的子菜單
    SubMenu colorMenu = menu.addSubMenu("字體顏色");
    colorMenu.setIcon(R.color.colorPrimaryDark);
//    設(shè)置菜單頭的圖標(biāo)
    colorMenu.setHeaderIcon(R.color.colorAccent);
//    設(shè)置菜單頭的標(biāo)題
    colorMenu.setHeaderTitle("選擇文字顏色");
    colorMenu.add(0, FONT_RED, 0, "紅色");
    colorMenu.add(0, FONT_GREEN, 0, "綠色");
    colorMenu.add(0, FONT_BLUE, 0, "藍(lán)色");

    return super.onCreateOptionsMenu(menu);
  }

//  選項(xiàng)菜單的菜單項(xiàng)被單擊后的回調(diào)方法
  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
//    判斷單擊的是哪個(gè)菜單項(xiàng)
    switch (item.getItemId()) {
      case FONT_10:
        editText.setTextSize(10 * 2);
        break;
      case FONT_12:
        editText.setTextSize(12 * 2);
        break;
      case FONT_14:
        editText.setTextSize(14 * 2);
        break;
      case FONT_16:
        editText.setTextSize(16 * 2);
        break;
      case FONT_18:
        editText.setTextSize(18 * 2);
        break;
      case FONT_RED:
        editText.setTextColor(Color.RED);
        break;
      case FONT_GREEN:
        editText.setTextColor(Color.GREEN);
        break;
      case FONT_BLUE:
        editText.setTextColor(Color.BLUE);
        break;
      case PLAIN_ITEM:
        Toast.makeText(MainActivity.this, "您單擊了普通菜單", Toast.LENGTH_SHORT).show();
        break;
    }
    return true;
  }
}

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto">

  <item android:id="@+id/file"
    android:icon="@drawable/ic_insert_drive_file_white_24dp"
    android:title="@string/file"
    app:showAsAction="ifRoom"/>
  <item android:id="@+id/newOne"
    android:icon="@drawable/ic_create_new_folder_white_24dp"
    android:title="@string/newOne"
    app:showAsAction="ifRoom">

    <menu>
      <item android:id="@+id/save"
        android:title="@string/save"/>
      <item android:id="@+id/paste"
        android:title="@string/paste"/>
    </menu>
  </item>
</menu>