Android：Urban Airship 6.0.1：android：提升找不到与给定名称匹配的资源

我正在尝试将urban Airship Library添加到我的项目中.我完全按照步骤操作,但是当我构建时,我得到了这个错误

No resource found that matches the given name: attr'android:elevation'


    <?xml version="1.0" encoding="utf-8"?>
<resources>
    <!-- From: file:/Users/build/workspace/android-library/UrbanAirship/src/main/res/values-v21/styles.xml -->
    <eat-comment/>
    <style name="Widget.UrbanAirship.InAppmessage.bAnner" parent="Base.Widget.UrbanAirship.InAppmessage.bAnner">
        <item name="android:BACkground">@drawable/ua_iam_BACkground</item>
        <item name="android:elevation">@dimen/ua_iam_bAnner_elevation</item>
    </style>
</resources>

这是我的gradle文件依赖项

compile 'com.android.support:support-v4:22.0.0'
compile 'com.android.support:cardview-v7:22.0.0'
compile 'com.google.android.gms:play-services-gcm:7.0.0'
compile 'com.google.android.gms:play-services-LOCATIOn:7.0.0'

我的targetSdkVersion是21,我还从SDK管理器更新了我的API

http://docs.urbanairship.com/platform/android.html供参考

请帮我.谢谢！

更新1：Android部分在gradle中

android {
    compileSdkVersion 19
    buildToolsVersion "21.1.1"

    defaultConfig {
        applicationId "com.example"
        minSdkVersion 14
        targetSdkVersion 21
        multiDexEnabled true
        renderscriptTargetApi 22
        renderscriptSupportModeEnabled true
    }

    dexOptions {
        javaMaxHeapSize "4g"
    }

    packagingOptions {
        exclude 'Meta-INF/DEPENDENCIEs.txt'
        exclude 'Meta-INF/LICENSE.txt'
        exclude 'Meta-INF/NOTICE.txt'
        exclude 'Meta-INF/NOTICE'
        exclude 'Meta-INF/LICENSE'
        exclude 'Meta-INF/DEPENDENCIES'
        exclude 'Meta-INF/notice.txt'
        exclude 'Meta-INF/license.txt'
        exclude 'Meta-INF/dependencies.txt'
        exclude 'Meta-INF/LGPL2.1'
    }
}