title: How to parse a JSONObject from Firebase realtime database into an ArrayList in Android?
body: <p>I want to parse JSONObject from Firebase realtime database into an ArrayList</p>
  
  <pre><code>ArrayList&lt;String&gt; username = new ArrayList&lt;String&gt;(); 
  ArrayList&lt;String&gt; password = new ArrayList&lt;String&gt;(); 
  ArrayList&lt;String&gt; picture_profile = new ArrayList&lt;String&gt;(); 
  </code></pre>
  
  <p>-----------------------------------json object----------------------------</p>
  
  <pre><code>{ 
     "testuser1": { 
        "password": "123456", 
        "picture_profile": "default" 
     }, 
     "testuser2": { 
        "password": "123456", 
        "picture_profile": "default" 
     } 
  }
  </code></pre>