Here I have created Popup function , Popup function can be used to display menu item list, anchor text and listitem etc. In the below example when we clicked on menu button the popup will be open and if we click outside the popup it will disappears.
Here in below code example I have explain how to make Popup function.
Step(1)- activity_main.xml

<RelativeLayout xmlns:androclass="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"  
    tools:context=".MainActivity" >  

    <Button  
        android:id="@+id/button1"  
        android:layout_width="wrap_content"  
        android:layout_height="wrap_content"  
        android:layout_alignParentLeft="true"  
        android:layout_alignParentTop="true"  
        android:layout_marginLeft="62dp"  
        android:layout_marginTop="50dp"  
        android:text="Show Item" />  

</RelativeLayout>

Step(2)- poupup_menu.xml

<menu xmlns:androclass="http://schemas.android.com/apk/res/android" >  

    <item  
        android:id="@+id/one"  
        android:title="Apple"/>  

    <item  
        android:id="@+id/two"  
        android:title="banana"/>  

    <item  
        android:id="@+id/three"  
        android:title="orange"/>  
           <item  
        android:id="@+id/four"  
        android:title="Mango"/>  
</menu>  

Step(3)-MainActivity-

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

          button1 = (Button) findViewById(R.id.button1);  
          button1.setOnClickListener(new OnClickListener() {  

           @Override  
           public void onClick(View v) {  
            PopupMenu popup = new PopupMenu(MainActivity.this, button1);  
            popup.getMenuInflater().inflate(R.menu.popup_menu, popup.getMenu()); 
            popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {  
             public boolean onMenuItemClick(MenuItem item) {  
              Toast.makeText(MainActivity.this,"Select this : " + item.getTitle(),Toast.LENGTH_SHORT).show();  
              return true;  
             }  
            });  

            popup.show();//showing popup menu  
           }  
          });
         }  
    }