docs/html/topic/performance/power/index.jd

page.title=Optimizing for Battery Life
page.metaDescription=Learn how to help your app go easier on the battery.

meta.tags="performance"
page.tags="performance"

@jd:body

<div id="qv-wrapper">
  <div id="qv">
    <h2>
      In this document
    </h2>
    <ol>
      <li>
        <a href="#lazy">Lazy First</a>
      </li>
      <li>
        <a href="#features">Platform Features</a>
      </li>
      <li>
        <a href="#toolery">Tooling</a>
      </li>
    </ol>
  </div>
</div>

<p>Battery life is the single most important aspect of the mobile user
experience. A device without power offers no functionality at all.
For this reason, it is critically important that apps be as respectful of
battery life as possible.</p>

<p>There are three important things to keep in mind in keeping your app
power-thrifty:</p>
<ul>
<li>Make your apps <em>Lazy First</em>.</li>
<li>Take advantage of platform features that can help manage your app's battery
consumption.</li>
<li>Use tools that can help you identify battery-draining culprits.</li>
</ul>

<h2 id="lazy">Lazy First</h2>

<p>Making your app Lazy First means looking for ways to reduce and optimize
operations that are particularly battery-intensive. The core questions
underpinning Lazy First design are:

<ul>

   <li><strong>Reduce:</strong> Are there redundant operations your app can cut
out? For example, can it cache downloaded data instead of repeatedly waking
   up the radio to re-download the data?</li>

   <li><strong>Defer:</strong> Does an app need to perform an action right
   away? For example,
    can it wait until the device is charging before it backs data up to the
    cloud?</li>

   <li><strong>Coalesce:</strong> Can work be batched, instead of putting the
   device
   into an active state many times? For example, is it really necessary for
   several dozen apps to each turn on the radio at separate times to send
   their messages? Can the messages instead be transmitted during a
   single awakening of the radio?</li>
</ul>

<p>
You should ask these questions when it comes to using the CPU,
the radio, and the screen. Lazy First design is often a good way
to tame these battery killers.
</p>

<p>
To help you achieve these and other efficiencies, the Android platform
provides a number of features to help maximize battery life.
</p>

<h2 id="features">Platform Features</h2>

<p>
Broadly speaking, the Android platform provides two categories of help
for you to optimize your app's battery use. First, it provides several
APIs that you can implement in your app. You can learn more about these APIs in
<a href="/topic/performance/scheduling.html">Intelligent Job Scheduling</a>
and <a href="/performance/power/network/index.html">
Network Use and Battery Consumption</a>.
</p>

<p>
There are also internal mechanisms in the platform to help conserve
battery life. While they are not APIs that you implement programmatically,
you should still be aware of them so that your app can leverage them
successfully. For more information, see
<a href="/training/monitoring-device-state/doze-standby.html">Doze and
App Standby</a>.</p>

<p>
You can get even more benefit out of these features by using the tools
available for the platform to discover the parts of your app that consume
the most power. Finding what to target is a big step toward
successful optimization.
</p>

<h2 id ="toolery">Tooling</h2>

<p>There are tools for Android, including
<a href="/studio/profile/dev-options-rendering.html">Profile GPU Rendering</a>
and <a class="external-link"
href="https://github.com/google/battery-historian">Battery Historian</a>
to help you identify areas that you can optimize for better battery life.
Take advantage of these tools to target areas where you can apply the
principles of Lazy First.
</p>

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