page.title=Progress and Activity
@jd:body

<p>When an operation of interest to the user is taking place over a relatively long period of time,
provide visual feedback that it's still happening and in the process of being completed.</p>
<h2 id="progress">Progress</h2>

<p>If you know the percentage of the operation that has been completed, use a determinate progress bar
to give the user a sense of how much longer it will take.</p>

<img src="{@docRoot}design/media/progress_download.png">

<p>The progress bar should always travel from 0% to 100% completion. Avoid setting the bar to a lower
value than a previous value, or using the same progress bar to represent the progress of multiple
events, since doing so makes the display meaningless. If you're not sure how long a particular
operation will take, use an indeterminate progress indicator.</p>

<div class="vspace size-2">&nbsp;</div>

<img src="{@docRoot}design/media/progress_themes.png">
<div class="figure-caption">
  Progress bar in Holo Dark and Holo Light.
</div>

<h2 id="activity">Activity</h2>

<p>If you don't know how much longer an operation will continue, use an indeterminate progress
indicator. There are two styles available: a flat bar and a circle. Use the one that best fits the
available space.</p>


<div class="layout-content-row">
  <div class="layout-content-col span-6">

    <img src="{@docRoot}design/media/progress_activity.png">

  </div>
  <div class="layout-content-col span-7 with-callouts">

    <ol>
      <li class="value-1"><h4>Activity bar (shown with the Holo Dark theme)</h4>
        <p>

An indeterminate activity bar is used at the start of an application download because the Play Store
app hasn't been able to contact the server yet, and it's not possible to determine how long it will
take for the download to begin.

        </p>
      </li>
    </ol>

  </div>
</div>

<div class="layout-content-row">
  <div class="layout-content-col span-6">

    <img src="{@docRoot}design/media/progress_activity2.png">

  </div>
  <div class="layout-content-col span-7 with-callouts">

    <ol>
      <li class="value-2"><h4>Activity circle (shown with the Holo Light theme)</h4>
        <p>

An indeterminate activity circle is used in the Gmail application when a message is being
loaded because it's not possible to determine how long it will take to download the email.

        </p>
      </li>
    </ol>

  </div>
</div>

<p>You should only use one activity indicator on screen per activity, and it should appropriately sized
for the surrounding context. For example, the largest activity circle works well when displayed in a
blank content area, but not in a smaller dialog box.</p>