Android, MongoDB, MongoLab Hosted Sample App Part One

In this tutorial, i introduce MongoDB and MongoLab,  a hosting service for MongoDB databases. I guide you on how to make your first Android MongoLab hosted application.

A MongoDB database is made up of collections and documents (structured). 

Collections: You can think about a collection as an SQL table. Collections group related documents together.

Documents (structured): You can think of documents as rows in an SQL table. Documents contain detailed information about a given object. e.g. You can have a document containing patient medical information. You can read more about mongodb from here.

Before you begin the tutorial, do tasks 1 – 4

1. Register on www.mongolab.com

2. Create a database named code101 (Choose the free sandbox 512MB)

3. Create a collection named docs101

4. Get your API key.  NB: You can find it by clicking on your user name in the top right corner and scrolling to the bottom of the page

The code is available for download from github.

 

Figure 1: Final Product

Create a new android application. NB: We are using REST and not the java driver.

The MyContact defines the data fields that are stored.

package com.wordpress.michaelkyazze.codeperspective101;

public class MyContact {

public String first_name;
public String last_name;
public String phone;
public String email;

}

 

The QueryBuilder class contains the code that builds the MongoHQ webservice. I have commented the code for your convenience

package com.wordpress.michaelkyazze.codeperspective101.MongoHQ;

import com.wordpress.michaelkyazze.codeperspective101.MyContact;

public class QueryBuilder {

 /**
 * Specify your database name here
 * @return
 */
 public String getDatabaseName() {
 return "code101";
 }

 /**
 * Specify your MongoLab API here
 * @return
 */
 public String getApiKey() {
 return ".....PUT YOUR API KEY HERE.......";
 }

 /**
 * This constructs the URL that allows you to manage your database,
 * collections and documents
 * @return
 */
 public String getBaseUrl()
 {
 return "https://api.mongolab.com/api/1/databases/"+getDatabaseName()+"/collections/";
 }

 /**
 * Completes the formating of your URL and adds your API key at the end
 * @return
 */
 public String docApiKeyUrl()
 {
 return "?apiKey="+getApiKey();
 }

 /**
 * Returns the docs101 collection
 * @return
 */
 public String documentRequest()
 {
 return "docs101";
 }

 /**
 * Builds a complete URL using the methods specified above
 * @return
 */
 public String buildContactsSaveURL()
 {
 return getBaseUrl()+documentRequest()+docApiKeyUrl();
 }

 /**
 * Formats the contact details for MongoHQ Posting
 * @param contact: Details of the person
 * @return
 */
 public String createContact(MyContact contact)
 {
 return String
 .format("{\"document\" : {\"first_name\": \"%s\", "
 + "\"last_name\": \"%s\", \"email\": \"%s\", "
 + "\"phone\": \"%s\"}, \"safe\" : true}",
 contact.first_name, contact.last_name, contact.email, contact.phone);
 }

}</pre>
<pre>

 

Android MainActivity Class Code:

package com.wordpress.michaelkyazze.codeperspective101;

import java.net.UnknownHostException;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import com.wordpress.michaelkyazze.codeperspective101.MongoHQ.SaveAsyncTask;

public class MainActivity extends Activity {
 EditText editText_last_name;
 EditText editText_phone;
 EditText editText_email;
 EditText editText_fname;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);

 editText_fname = (EditText) findViewById(R.id.editText_fname);
 editText_last_name = (EditText) findViewById(R.id.editText_last_name);
 editText_email = (EditText) findViewById(R.id.editText_email);
 editText_phone = (EditText) findViewById(R.id.editText_phone);

 }

 public void saveContact(View v) throws UnknownHostException {

 MyContact contact = new MyContact();
 contact.first_name = editText_fname.getText().toString();
 contact.last_name = editText_last_name.getText().toString();
 contact.email = editText_email.getText().toString();
 contact.phone = editText_phone.getText().toString();

 SaveAsyncTask tsk = new SaveAsyncTask();
 tsk.execute(contact);

 }

}

 

The contact is now saved in your MongoLab Database. To view it, simply browse to your docs101 collection at Mongolab.com. The Next part of the tutorial will cover Reading,Updating and Deleting

“Happy Coding :)”