cherrypick Change-Id: I7a3612a1bc22cf53d382f787fa43fe222978d35e

For more information on creating animators, see the sections on animating with

<a href="#value-animator">ValueAnimator</a> and <a href="#object-animator">ObjectAnimator</a>

<h2 id="declaring-xml">Declaring Animations in XML</h2>

  <p>The property animation system lets you declare property animations with XML instead of doing

  it programmatically. The following Android classes have XML declaration support with the

  it programmatically. By defining your animations in XML, you can easily reuse your animations

in multiple activities and more easily edit the animation sequence.</p>

<p>To distinguish animation files that use the new property animation APIs from those that use the

legacy <a href="{@docRoot}guide/topics/graphics/view-animation.html">view animation</a> framework,

starting with Android 3.1, you should save the XML files for property animations in the {@code

res/animator/} directory (instead of {@code res/anim/}). Using the {@code animator} directory name

is optional, but necessary if you want to use the layout editor tools in the Eclipse ADT plugin (ADT

11.0.0+), because ADT only searches the {@code res/animator/} directory for property animation

resources.</p>

<p>The following property animation classes have XML declaration support with the

  following XML tags:</p>

  <ul>

    beginning each time.</dd>

  </dl>

  <p>The <code>objectAnimator</code> ({@link android.animation.ObjectAnimator}) element has the

  additional attribute <code>propertyName</code>, that lets you specify the name of the property

  being animated. The <code>objectAnimator</code> element does not expose a <code>target</code>

  <p>The <code>&lt;objectAnimator&gt;</code> ({@link android.animation.ObjectAnimator}) element has the

  additional attribute <code>android:propertyName</code>, that lets you specify the name of the

property

  being animated. The <code>&lt;objectAnimator&gt;</code> element does not expose a <code>target</code>

  attribute, however, so you cannot set the object to animate in the XML declaration. You have to

  inflate the XML resource by calling {@link android.animation.AnimatorInflater#loadAnimator

  loadAnimator()} and call {@link android.animation.ObjectAnimator#setTarget setTarget()} to set

  the target object unlike the underlying {@link android.animation.ObjectAnimator},

  before calling {@link android.animation.ObjectAnimator#start start()}.</p>

  <p>The <code>set</code> element ({@link android.animation.AnimatorSet}) exposes a single

  attribute, <code>ordering</code>. Set this attribute to <code>together</code> (default) to play

  all the animations in this set at once. Set this attribute to <code>sequentially</code> to play

  <p>The <code>&lt;set&gt;</code> element ({@link android.animation.AnimatorSet}) exposes a single

  attribute, <code>android:ordering</code>. Set this attribute to <code>"together"</code> (default)

to play

  all the animations in this set at once. Set this attribute to <code>"sequentially"</code> to play

  the animations in the order they are declared.</p>

  <p>You can specify nested <code>set</code> tags to further group animations together. The

  animations that you want to group together should be children of the <code>set</code> tag and can

  <p>You can specify nested <code>&lt;set&gt;</code> elements to further group animations together.

The

  animations that you want to group together should be children of the <code>&lt;set&gt;</code> tag and can

  define their own <code>ordering</code> attribute.</p>

  <p>As an example, this XML code creates an {@link android.animation.AnimatorSet} object that

  before starting the animation set. Calling {@link android.animation.AnimatorSet#setTarget

  setTarget()} sets a single target object for all children of the {@link

  android.animation.AnimatorSet}.</p>

<p class="note"><strong>Tip:</strong> To see how the ADT layout editor allows you to develop and

preview animations in your layout, watch the <a

href="http://www.youtube.com/watch?v=Oq05KqjXTvs&feature=player_detailpage#t=1709s">Android

Developer Tools session</a> from Google I/O '11</p>

    <th scope="col">Resource Type</th>

  </tr>

  <tr>

    <td><code>animator/</code></td>

    <td>XML files that define <a href="{@docRoot}guide/topics/graphics/animation.html">property

animations</a>.</td>

  </tr>

  <tr>

    <td><code>anim/</code></td>

    <td>XML files that define tween animations. See <a

href="animation-resource.html">Animation Resources</a>.</td>

    <td>XML files that define <a

href="{@docRoot}guide/topics/graphics/view-animation.html#tween-animation">tween

animations</a>. (Property animations can also be saved in this directory, but

the {@code animator/} directory is preferred for property animations to distinguish between the two

types.)</td>

  </tr>

  <tr>