在activity中使用menu

一：在res中新建一个menu的文件夹，然后在文件夹下面建一个main.xml文件，xml的代码如下

1 <?xml version="1.0" encoding="utf-8"?>
2 <menu xmlns:android="http://schemas.android.com/apk/res/android" >
3     <item 
4         android:id="@+id/add_item"
5         android:title="Add"/>
6     <item 
7         android:id="@+id/remove_item"
8         android:title="Remove"/>

二：在,MainActivity.java重写onCreateOptionsMenu()方法，在MainActivty.java中重写onOptionsItemSelected()方法，代码如下

 1 package menudemo.zhangmeng.com.menudemo;
 2 
 3 import android.support.v7.app.AppCompatActivity;
 4 import android.os.Bundle;
 5 import android.view.Menu;
 6 import android.view.MenuItem;
 7 import android.widget.Toast;
 8 
 9 public class MainActivity extends AppCompatActivity {
10 
11     @Override
12     protected void onCreate(Bundle savedInstanceState) {
13         super.onCreate(savedInstanceState);
14         setContentView(R.layout.activity_main);
15     }
16 
17     @Override
18     public boolean onCreateOptionsMenu(Menu menu) {
19         getMenuInflater().inflate(R.menu.main,menu);
20         return true;
21     }
22 
23     @Override
24     public boolean onOptionsItemSelected(MenuItem item) {
25         switch (item.getItemId()){
26             case R.id.add_item:
27                 Toast.makeText(this, "you clicked add", Toast.LENGTH_SHORT).show();
28                 break;
29             case R.id.remove_item:
30                 Toast.makeText(this, "you clicked remove", Toast.LENGTH_SHORT).show();
31             default:
32         }
33         return true;
34 
35     }
36 }