“Failed to convert ?attr/colorPrimary into a drawable”

Question

I am starting a new project, so the project is more or less "empty". I just added a MainActivity, with a MainActivityFragment. I haven't added any code at all to them.

Now, I edit the styles.xml so it looks like this:

<resources>
    <!-- Base application theme. -->
    <style name="MyTheme" parent="@android:style/Theme.Material.Light.DarkActionBar">
        <item name="android:windowNoTitle">true</item>
        <!--We will be using the toolbar so no need to show ActionBar-->
        <item name="android:windowActionBar">false</item>
        <!-- Set theme colors from http://www.google.com/design/spec/style/color.html#color-color-palette-->
        <!-- colorPrimary is used for the default action bar background -->
        <item name="android:colorPrimary">#2196F3</item>
        <!-- colorPrimaryDark is used for the status bar -->
        <item name="android:colorPrimaryDark">#1976D2</item>
        <!-- colorAccent is used as the default value for colorControlActivated
             which is used to tint widgets -->
        <item name="android:colorAccent">#FF4081</item>
        <!-- You can also set colorControlNormal, colorControlActivated
             colorControlHighlight and colorSwitchThumbNormal. -->
        <item name="toolbarStyle">@style/Widget.AppCompat.Toolbar</item>
    </style>
</resources>

So, I extend the Material theme as you can see.

I then create a toolbar xml file (mytoolbar.xml), like this:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/toolbar1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="?attr/actionBarSize"
    android:background="?attr/colorPrimary">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/abc_ic_voice_search_api_mtrl_alpha"/>
</android.support.v7.widget.Toolbar>

And here is the problem:

I can't figure out why. I have done gradle sync, clean, rebuild, restarted IDE (Android Studio 1.2.1.1), nothing works.

Any ideas?

Answer 1

There is a bug in android [pre-lollipop] OS which doesnt allow you to use attr in drawable. Here is the link to bug:

https://code.google.com/p/android/issues/detail?id=26251

Android dev team has released a fix but it works on android L and above. For workaround to this problem, refer to following solution:

How to reference style attributes from a drawable?

Answer 2

Prepend android keyword to it.

?attr/colorPrimary"

becomes

?android:attr/colorPrimary

working fine in android studio 3.0 .

Answer 3

There is problem on below Android OS version -21 .You can use

android:background="?attr/colorPrimary"

instead of

app:background="?attr/colorPrimary"

It will work fine.