How to reference a theme attribute in a style?

I've got a following problem. I want to customize appearance of row in a list, but exception is thrown during inflating.

piece of code in style.xml

<style name="AppTheme.Main"> <item name="item_shadowColor">#000000</item> </style> <style name="item_label"> <item name="android:shadowColor">?attr/item_shadowColor</item> </style> 

attr.xml

<?xml version="1.0" encoding="utf-8"?> <resources> <attr name="item_shadowColor" format="color" /> </resources> 

list_item.xml

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="horizontal" > <TextView android:id="@id/title" style="@style/item_label" android:layout_width="fill_parent" android:layout_height="fill_parent"/> </LinearLayout> 

And the exception

FATAL EXCEPTION: main android.view.InflateException: Binary XML file line #7: Error inflating class <unknown> at android.view.LayoutInflater.createView(LayoutInflater.java:606) at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56) at android.view.LayoutInflater.onCreateView(LayoutInflater.java:653) at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:678) at android.view.LayoutInflater.rInflate(LayoutInflater.java:739) at android.view.LayoutInflater.inflate(LayoutInflater.java:489) at android.view.LayoutInflater.inflate(LayoutInflater.java:396) at ru.mts.goodok.adapter.CategoryListAdapter.getView(CategoryListAdapter.java:30) at android.widget.AbsListView.obtainView(AbsListView.java:2052) at android.widget.ListView.makeAndAddView(ListView.java:1820) at android.widget.ListView.fillDown(ListView.java:672) at android.widget.ListView.fillFromTop(ListView.java:732) at android.widget.ListView.layoutChildren(ListView.java:1673) at android.widget.AbsListView.onLayout(AbsListView.java:1882) at android.view.View.layout(View.java:11425) at android.view.ViewGroup.layout(ViewGroup.java:4232) at android.widget.RelativeLayout.onLayout(RelativeLayout.java:925) at android.view.View.layout(View.java:11425) at android.view.ViewGroup.layout(ViewGroup.java:4232) at android.widget.FrameLayout.onLayout(FrameLayout.java:431) at android.view.View.layout(View.java:11425) at android.view.ViewGroup.layout(ViewGroup.java:4232) at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1628) at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1486) at android.widget.LinearLayout.onLayout(LinearLayout.java:1399) at android.view.View.layout(View.java:11425) at android.view.ViewGroup.layout(ViewGroup.java:4232) at android.widget.FrameLayout.onLayout(FrameLayout.java:431) at android.view.View.layout(View.java:11425) at android.view.ViewGroup.layout(ViewGroup.java:4232) at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1516) at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2505) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:154) at android.app.ActivityThread.main(ActivityThread.java:4945) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:511) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) at dalvik.system.NativeStart.main(Native Method) Caused by: java.lang.reflect.InvocationTargetException at java.lang.reflect.Constructor.constructNative(Native Method) at java.lang.reflect.Constructor.newInstance(Constructor.java:417) at android.view.LayoutInflater.createView(LayoutInflater.java:586) ... 39 more Caused by: java.lang.NumberFormatException: Invalid int: "?2130771972" at java.lang.Integer.invalidInt(Integer.java:138) at java.lang.Integer.parse(Integer.java:375) at java.lang.Integer.parseInt(Integer.java:366) at com.android.internal.util.XmlUtils.convertValueToInt(XmlUtils.java:123) at android.content.res.TypedArray.getInt(TypedArray.java:254) at android.widget.TextView.<init>(TextView.java:829) at android.widget.TextView.<init>(TextView.java:489) ... 42 more 

What am I doing wrong and how could I solve this problem?