title: Apply different style to app
body: <p>I want to create android app in which user can set custom theme, Like blue, and red. I have created 2 <code>Activities</code>, From <code>Activity-1</code> user can select color. But is it possible to change app theme programmatically?</p>
  
  <p>My styles are:</p>
  
  <pre><code> &lt;!-- Base application theme. --&gt;
  &lt;style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar"&gt;
      &lt;!-- Customize your theme here. --&gt;
      &lt;item name="colorPrimary"&gt;@color/color_primary&lt;/item&gt;
      &lt;item name="colorPrimaryDark"&gt;@color/color_primary_dark&lt;/item&gt;
      &lt;item name="colorAccent"&gt;@color/accent_color&lt;/item&gt;
  &lt;/style&gt;
  
  &lt;style name="RedTheme" parent="Theme.AppCompat.Light.NoActionBar"&gt;
      &lt;!-- Customize your theme here. --&gt;
      &lt;item name="colorPrimary"&gt;@color/color_red&lt;/item&gt;
      &lt;item name="colorPrimaryDark"&gt;@color/color_red&lt;/item&gt;
      &lt;item name="colorAccent"&gt;@color/color_red&lt;/item&gt;
  &lt;/style&gt;
  </code></pre>
  
  <p>My toolbar</p>
  
  <pre><code>&lt;android.support.v7.widget.Toolbar
          android:id="@+id/toolbar"
          android:background="@color/color_primary"
          android:layout_width="match_parent"
          android:layout_height="?attr/actionBarSize"&gt;
      &lt;/android.support.v7.widget.Toolbar&gt;
  </code></pre>
  
  <p>I tried using <code>setTheme(R.style.RedTheme)</code> but it does not change Toolbar color. </p>
  
  <p>Please suggest me.</p>
  
  <p>Thank you.</p>