为Android应用添加菜单和子菜单

package com.example.yangjian.leagngjian;

import android.graphics.Color;
import android.support.v7.app.ActionBarActivity;
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 ActionBarActivity {

// 定义字体大小菜单项的标识
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;
// 定义字体颜色菜单项的标识
final int PLAIN_ITEM = 0x11b;
// 定义字体颜色菜单项的标识
final int FONT_RED = 0X116;
final int FONT_BLUE = 0X117;
final int FONT_GREEN = 0X118;
private EditText edit;

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

// 当用户单击MENU键时触发该方法
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
//getMenuInflater().inflate(R.menu.menu_main, menu);
//return true;
//----------向menu中添加字体大小的子菜单----------------
SubMenu fontMenu = menu.addSubMenu("字体大小");
// 设置菜单的图标
fontMenu.setIcon(R.drawable.font);
// 设置菜单头的图标
fontMenu.setHeaderIcon(R.drawable.font);
// 设置菜单头的标题
fontMenu.setHeaderTitle("选择字体大小");
fontMenu.add(0, FONT_10, 0, "10号字体");
fontMenu.add(0, FONT_12, 0, "12号字体");
fontMenu.add(0, FONT_14, 0, "14号字体");
fontMenu.add(0, FONT_16, 0, "16号字体");
fontMenu.add(0, FONT_18, 0, "18号字体");
// --------向menu中添加普通菜单项------------
menu.add(0, PLAIN_ITEM, 0, "普通菜单项");
// ------向menu中添加文字颜色的子菜单---------
SubMenu colorMenu = menu.addSubMenu("字体颜色");
colorMenu.setIcon(R.drawable.color);
// 设置菜单头的图标
colorMenu.setHeaderTitle("选择文字颜色");
colorMenu.add(0, FONT_RED, 0, "红色");
colorMenu.add(0, FONT_BLUE, 0, "蓝色");
colorMenu.add(0, FONT_GREEN, 0, "绿色");
return super.onCreateOptionsMenu(menu);

}

// 选项菜单的菜单项被单击后的回调方法

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
// int id = item.getItemId();

//noinspection SimplifiableIfStatement
// if (id == R.id.action_settings) {
// return true;
//}

//return super.onOptionsItemSelected(item);
// 判断单击的是哪个菜单项，并有针对性地作出响应
switch (item.getItemId()) {
case FONT_10:
edit.setTextSize(10 * 2);
break;
case FONT_12:
edit.setTextSize(12 * 2);
break;
case FONT_14:
edit.setTextSize(14 * 2);
break;
case FONT_16:
edit.setTextSize(16 * 2);
break;
case FONT_18:
edit.setTextSize(18 * 2);
break;
case FONT_RED:
edit.setTextColor(Color.RED);
break;
case FONT_BLUE:
edit.setTextColor(Color.BLUE);
break;
case FONT_GREEN:
edit.setTextColor(Color.GREEN);
break;
case PLAIN_ITEM:
Toast toast = Toast.makeText(MainActivity.this, "您单击了普通菜单项", Toast.LENGTH_SHORT);
toast.show();
break;
}
return true;
}
}

第二步：在Main_xml文件中代码如下：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/txt"/>

</LinearLayout>