Question: Before upgrading to `android 3.1`.I usually just change the theme to a theme. app compact. `NoTitleBar` but the new version of `android studio` is having errors recognizing it.I solved this problem by adding base to the beginning. But I can seem to find any answer regarding a style theme that supports removing the custom bar.

Answer: 
```
Add this style in style file . where other styles are mentioned . 

<!-- Base application theme. -->
<style name="AppThemeNoActionBar" parent="Theme.AppCompat.Light.NoActionBar">
    <item name="colorPrimary">@color/colorPrimaryDark</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorPrimaryDark</item>
    <item name="android:statusBarColor">@color/lightgreycolor</item>
</style>

```
In my case, i had to change parent theme in res/values/themes.xml

[![enter image description here](https://i.stack.imgur.com/Jbc7L.png)](https://i.stack.imgur.com/Jbc7L.png)