title: How to update my project creating a multi theme app
body: <p>I'd like to make a <code>SettingsActivity</code> to let the user personalize the appearence of the app.
  In this activity the user can choose to keep the app in a "<em>light theme</em>" (that means for example white backgrounds with black texts) or a "<em>dark theme</em>", the opposite colours of light theme to favour the night use. </p>
  
  <p>How could it be done? </p>
  
  <p>I was thinking about creating different layouts in xml for each theme.</p>
  
  <p><strong>EDITS</strong></p>
  
  <p>The images below are examples of <code>SettingsActivity</code>, I'd like to change the appearence for the whole app, not single activity.</p>
  
  <p><a href="https://i.stack.imgur.com/xa1iu.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/xa1iu.jpg" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/Svbwt.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Svbwt.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/N0iC4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/N0iC4.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/FjVD2.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FjVD2.png" alt="enter image description here"></a></p>