Android Flip animation using frame layout

I am new to android Animation and working on an Application in which I want to flip image view and want to show other image means front and back is having different images for this I used 2 fragments for each side and connected with frame layout as it is available in documentation of Android developer I am following exactly the same thing but I have got errors on compile time Here is xml object animator code of my app

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<!-- Rotate. -->
<objectAnimator
    android:valueFrom="-180"
    android:valueTo="0"
    android:propertyName="rotationY"
    android:interpolator="@android:interpolator/accelerate_decelerate"
    android:duration="@integer/card_flip_time_full" />

<!-- Half-way through the rotation (see startOffset), set the alpha to 1. -->
<objectAnimator
    android:valueFrom="0.0"
    android:valueTo="1.0"
    android:propertyName="alpha"
    android:startOffset="@integer/card_flip_time_half"
    android:duration="1" />

` No resource found that matches the given name (at 'startOffset' with value '@integer/card_flip_time_half').