Android学习笔记--Menu菜单的使用

实现选项菜单、上下文菜单，以及菜单内部的子菜单。

视图效果：

MainActivity	选项菜单	选项菜单的子菜单	上下文菜单(按住按钮或者EditText弹出)

注意：上下文菜单如何弹出？在注册该菜单的视图上按住一段时间后就会弹出菜单。

MainActivity.java

package com.evor.test;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MenuItem.OnMenuItemClickListener;
import android.view.SubMenu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button btn1 = (Button)findViewById(R.id.btn1);
        EditText edt1 = (EditText)findViewById(R.id.edt1);
        //注册上下文菜单（按住该视图一段时间后就会出现menu）
        registerForContextMenu(btn1);
        registerForContextMenu(edt1);
    }

    //实现选项菜单
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        //参数： groupid,itemid,order,titleRes
        MenuItem item1 = menu.add(1,1,1,"菜单项1");
        MenuItem item2 = menu.add(1,2,2,"菜单项2");
        MenuItem item3 = menu.add(1,3,3,"菜单项3");
        item3.setIntent(new Intent(this,MainActivity.class)); //设定关联的Activity，点击后会转到该activity

        MyOnMenuItemClickListener menuItemClickListener = new MyOnMenuItemClickListener();
        item1.setOnMenuItemClickListener(menuItemClickListener);
        item2.setOnMenuItemClickListener(menuItemClickListener);
        item3.setOnMenuItemClickListener(menuItemClickListener);

        //添加子菜单
        SubMenu fileSubMenu = menu.addSubMenu(1,4,4,"文件");
        MenuItem submenuItem1 = fileSubMenu.add(1,5,2,"新建");
        MenuItem submenuItem2 = fileSubMenu.add(2,6,3,"打开");
        MenuItem submenuItem3 = fileSubMenu.add(2,7,4,"退出");
        submenuItem1.setCheckable(true); //设置为多选框
        submenuItem2.setChecked(false); //设置是否被勾选
        submenuItem3.setChecked(true);    //设置是否被勾选
        fileSubMenu.setGroupCheckable(2, true, true);     //第三参数确定为单选还是多选
        return true;
    }

    //内部类--选项菜单的菜单项响应类
    private class MyOnMenuItemClickListener implements OnMenuItemClickListener{
        @Override
        public boolean onMenuItemClick(MenuItem item) {
            switch(item.getItemId()){
            case 1 : {Toast.makeText(MainActivity.this, "点击了菜单项1", Toast.LENGTH_SHORT).show(); break;}
            case 2 : {Toast.makeText(MainActivity.this, "点击了菜单项2", Toast.LENGTH_SHORT).show(); break;}
            case 3 : {Toast.makeText(MainActivity.this, "点击了菜单项3", Toast.LENGTH_SHORT).show(); break;}
            }
            return true;
        }
    } 

    //上下文菜单的回调函数
    @Override
    public void onCreateContextMenu(ContextMenu menu,View view,ContextMenuInfo menuInfo){
        super.onCreateContextMenu(menu, view, menuInfo);
        menu.setHeaderTitle("上下文菜单");
        int itemid = 0;
        menu.add(0,itemid++, Menu.NONE, "菜单项1");
        menu.add(0,itemid++, Menu.NONE, "菜单项2");
        menu.add(0,itemid++, Menu.NONE, "菜单项3");

        SubMenu subMenu = menu.addSubMenu("子菜单");
        subMenu.add("选项1");
        subMenu.add("选项2");
    }

    //菜单事件
    @Override
    public boolean onPrepareOptionsMenu(Menu menu){
        //在显示选项菜单之前被调用，一般可用来修改即将显示的选项菜单
        super.onPrepareOptionsMenu(menu);
        return true;
    }

    @Override
    public void onOptionsMenuClosed(Menu menu){
        //在关闭选项菜单时被调用
        super.onOptionsMenuClosed(menu);
    }

    @Override
    public void onContextMenuClosed(Menu menu) {
        // 在关闭上下文菜单时调用
        super.onContextMenuClosed(menu);
    }

    @Override
    public boolean onMenuOpened(int featureId, Menu menu) {
        //在显示选项菜单之前调用,该方法在onPrepareOptionsMenu方法之后调用
        return super.onMenuOpened(featureId, menu);
    }
}

activity_main.xml

<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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context="com.evor.test.MainActivity" >
    <Button
        android:id="@+id/btn1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="关联菜单的按钮"
        />
    <EditText
        android:id="@+id/edt1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="关联菜单的编辑框"
        />
</LinearLayout>