No resource found that matches the given name attr "colorPrimary"

This is what worked for my project.

In res/values-v21/styles.xml,

<?xml version="1.0" encoding="UTF-8"?><resources>    <style name="AppTheme" parent="@android:style/Theme.Material.Light.DarkActionBar">    <item name="android:colorPrimary">@color/primaryColor</item>    </style></resources>

In res/values/styles.xml,

<?xml version="1.0" encoding="utf-8"?><resources>    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">        <item name="colorPrimary">@color/primaryColor</item>    </style></resources>

You should follow the convention directly from the Material Design documentation(https://developer.android.com/training/material/theme.html#ColorPalette):

<resources>  <!-- inherit from the material theme -->  <style name="AppTheme" parent="android:Theme.Material">    <!-- Main theme colors -->    <!--   your app branding color for the app bar -->    <item name="android:colorPrimary">@color/primary</item>    <!--   darker variant for the status bar and contextual app bars -->    <item name="android:colorPrimaryDark">@color/primary_dark</item>    <!--   theme UI controls like checkboxes and text fields -->    <item name="android:colorAccent">@color/accent</item>  </style></resources>

What you are missing here is the android: namespace prefix to the colorPrimary item. Because of this, it cannot find the respective attribute as it's not defined in the scope.

Otherwise you would need to remove the android: prefix from the theme

parent="@android:style/Theme.Material.Light.DarkActionBar"

In my case, the colors used in styles.xml where not defined. So,make sure u have defined all the colors as well as names properly.