How to make action bar transparent in Android studio

Try this :

Styles.xml

2. ... 
3.  
4.  
6. @null 
7. true 
8. @android:color/transparent 
9.  
10.  
12. false 
13. @color/default_yellow 
14.  

Use these themes in your AndroidManifest.xml to specify which activities will have a transparent or colored ActionBar

2. android:name=".MyTransparentActionbarActivity" 
3. android:theme="@style/AppTheme.ActionBar.Transparent"/> 
4.  
6. android:name=".MyColoredActionbarActivity" 
7. android:theme="@style/AppTheme.ActionBar"/>