If you want to change the enter key to search key, here is the code to get the same:-

Step 1:- In your xml file add the following EditText

 <EditText 
                 android:id="@+id/ed_search_key"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content" 
                 android:gravity="left"
                 android:minWidth="100dp"
                 android:maxWidth="100dp"
                 android:maxLines="1"
                 android:inputType="text"
                 android:imeOptions="actionSearch"               
                 android:textColor="@color/white"
                 android:imeActionLabel="Search"
                 android:layout_gravity="center_horizontal">
    </EditText>

Step 2:- Set OnEditorActionListener to the EditText:-

 EditText edSearch= (EditText) findViewById(R.id.ed_search_key);
edSearch.setOnEditorActionListener(new TextView.OnEditorActionListener() { 
@Override 
 public boolean onEditorAction(TextView v, int actionId, KeyEvent event)
      { 
         if (actionId == EditorInfo.IME_ACTION_SEARCH)
           {
              /* Here you can add your code, what and how you want to search */
              Toast.makeText(getApplicationContext(),"Searching clicked", Toast.LENGTH_SHORT).show();
               return true;
             }
              return false;
         }  
        });