tests/res/anim/cycle_alpha.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 -->

<alpha xmlns:android="http://schemas.android.com/apk/res/android"
       android:interpolator="@anim/cycle_interpolator"
       android:fromAlpha="0.0"
       android:toAlpha="1.0"
       android:duration="2000" />