Android Context Menu Example

           In this tutorial I will show you how to create a context menu. A context menu is a menu that appears when a user long-presses a view.

           I am assuming that you already have a list of items that you will use, but if you don't you can quickly create one following the three steps of my ListView tutorial here:

http://tk-tutorials.blogspot.com/2013/06/android-listview-example.html 

1. Creating a menu and adding items to it

          So the first thing that we need to do here is to create a menu and add items to it:) It is possible to create a menu through a code, but in my opinion it is easier to do it through XML file that is to be located in theres\menu directory. 

            Go to res\menu directory and create a new XML file (right click on menu folder New->Android XML file), add the following code to it: 

 <?xml version="1.0" encoding="utf-8"?>  
 <menu xmlns:android="http://schemas.android.com/apk/res/android" >  
   <item   
    android:id="@+id/delete_item"  
    android:title="@string/delete_string"  
     />  
 </menu>  

              As you can see I have added one item to our menu and used a string resource for its title. To create a string resource you need to go to the res\values directory, open a strings.xml file and add this tine to it:

 <string name="delete_string">Delete</string>  

2. Registering a context menu
Go to the ActivityMain.java file and add the following line to the onCreate() method:

 registerForContextMenu(getListView());  

registerForContextMenu() is registering our context menu to be shown in this view. When the items of your list is clicked the registerForContextMenu() calls onCreateContextMenu() method, where your context menu is being set up. So now we need to add this method:

 @Override  
   public void onCreateContextMenu(ContextMenu menu, View v,  
             ContextMenuInfo menuInfo) {  
        // TODO Auto-generated method stub  
        super.onCreateContextMenu(menu, v, menuInfo);  
        MenuInflater m = getMenuInflater();  
        m.inflate(R.menu.our_context_menu, menu);  
   }  

Now that we have defined what menu is going to be inflated in the menu object we can continue to the next step.

3. Handling the item selection
To handle the selection of a context menu item add the following code:

 @Override  
   public boolean onContextItemSelected(MenuItem item) {  
        switch(item.getItemId()){  
             case R.id.delete_item:  
                  AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();  
                  position = (int) info.id;  
                  list.remove(position);  
                  this.adapter.notifyDataSetChanged();  
                  return true;  
        }  
        return super.onContextItemSelected(item);  
   }  

Explanation:
         This method is the one that is going to be called when a context menu items is selected. A switch statement is used to find out which item was selected. We only have one item, which is meant to delete an item from the list. To do that we perform the following actions:

• get all the information about selected item using:

 AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();   

• get item's position in our list (info.id) and since this value is long we convert it to int type (because we need int:)
• remove selected item from our ArrayList with: 

 list.remove(position);  

• notify our adapter of change that had been made:

 this.adapter.notifyDataSetChanged();   

Full activity code:

 package com.example.contextmenuexample;  
 import java.util.ArrayList;  
 import java.util.Collections;  
 import java.util.List;  
 import android.os.Bundle;   
 import android.app.ListActivity;   
 import android.view.ContextMenu;  
 import android.view.MenuInflater;  
 import android.view.MenuItem;  
 import android.view.View;  
 import android.view.ContextMenu.ContextMenuInfo;  
 import android.widget.ArrayAdapter;   
 import android.widget.AdapterView.AdapterContextMenuInfo;  
  public class MainActivity extends ListActivity {   
       private String[] items;  
       private List<String> list;  
       private ArrayAdapter<String> adapter;  
       private int position;  
    @Override   
    protected void onCreate(Bundle savedInstanceState) {   
       super.onCreate(savedInstanceState);   
       setContentView(R.layout.activity_main);   
       fillData();   
       registerForContextMenu(getListView());  
    }   
    private void fillData() {   
       items = new String[] {"Monday", "Tuesday", "Wednesday",    
               "Thursday", "Friday", "Saturday", "Sunday"};  
       list = new ArrayList<String>();  
       Collections.addAll(list, items);  
       adapter = new ArrayAdapter<String>(this, R.layout.row, R.id.r_text, list);   
       setListAdapter(adapter);        
    }   
    @Override  
   public void onCreateContextMenu(ContextMenu menu, View v,  
             ContextMenuInfo menuInfo) {  
        // TODO Auto-generated method stub  
        super.onCreateContextMenu(menu, v, menuInfo);  
        MenuInflater m = getMenuInflater();  
        m.inflate(R.menu.our_context_menu, menu);  
   }  
    @Override  
   public boolean onContextItemSelected(MenuItem item) {  
        switch(item.getItemId()){  
             case R.id.delete_item:  
                  AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();  
                  position = (int) info.id;  
                  list.remove(position);  
                  this.adapter.notifyDataSetChanged();  
                  return true;  
        }  
        return super.onContextItemSelected(item);  
   }  
  }   

DEMO

Android Context Menu Example

Source code