Error: 'F' is not a valid file-based resource name character: File-based resource names must contain only lowercase a-z, 0-9, or underscore
<p><strong>Error:</strong> </p>

<p><code>'F' is not a valid file-based resource name character: File-based resource names must contain only lowercase a-z, 0-9, or underscore</code></p>

<pre><code> &lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;set xmlns:android="http://schemas.android.com/apk/res/android"&gt;
&lt;alpha
    android:duration="2000"
    android:fromAlpha="0.0"
    android:toAlpha="1.0"
    android:interpolator="@android:anim/accelerate_interpolator" /&gt;
&lt;/set&gt;
</code></pre>

<p>Where is the mistake? I do not see</p>