75 lines
2.9 KiB
Plaintext
75 lines
2.9 KiB
Plaintext
page.title=Managing the Activity Lifecycle
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trainingnavtop=true
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startpage=true
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next.title=Launching an Activity
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next.link=starting.html
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@jd:body
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<div id="tb-wrapper">
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<div id="tb">
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<h2>Dependencies and prerequisites</h2>
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<ul>
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<li>How to create an Android project (see <a
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href="{@docRoot}training/basics/firstapp/creating-project.html">Creating an Android
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Project</a>)</li>
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</ul>
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<h2>You should also read</h2>
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<ul>
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<li><a href="{@docRoot}guide/components/activities.html">Activities</a></li>
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</ul>
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<h2>Try it out</h2>
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<div class="download-box">
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<a href="http://developer.android.com/shareables/training/ActivityLifecycle.zip"
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class="button">Download the demo</a>
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<p class="filename">ActivityLifecycle.zip</p>
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</div>
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</div>
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</div>
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<p>As a user navigates through, out of, and back to your app, the
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{@link android.app.Activity} instances in your app transition between different states in their
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lifecycle. For instance, when your
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activity starts for the first time, it comes to the foreground of the system and receives user
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focus. During this process, the Android system calls a series of lifecycle methods on the
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activity in which you set up the user interface and other components. If the user performs an
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action that starts another activity or switches to another app, the system calls another set of
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lifecycle methods on your activity as it moves into the background (where the activity is no
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longer visible, but the instance and its state remains intact).</p>
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<p>Within the lifecycle callback methods, you can declare how your activity behaves when the
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user leaves and re-enters the activity. For example, if you're building a streaming video player,
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you might pause the video and terminate the network connection when the user switches to another
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app. When the user returns, you can reconnect to the network and allow the user to resume the video
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from the same spot.</p>
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<p>This class explains important lifecycle callback methods that each {@link
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android.app.Activity} instance receives and how you can use them so your activity does what the
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user expects and does not consume system resources when your activity doesn't need them.</p>
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<h2>Lessons</h2>
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<dl>
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<dt><b><a href="starting.html">Starting an Activity</a></b></dt>
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<dd>Learn the basics about the activity lifecycle, how the user can launch your app, and how
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to perform basic activity creation.</dd>
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<dt><b><a href="pausing.html">Pausing and Resuming an Activity</a></b></dt>
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<dd>Learn what happens when your activity is paused (partially obscured) and resumed and what you
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should do during these state changes.</dd>
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<dt><b><a href="stopping.html">Stopping and Restarting an Activity</a></b></dt>
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<dd>Learn what happens when the user completely leaves your activity and returns to it.</dd>
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<dt><b><a href="recreating.html">Recreating an Activity</a></b></dt>
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<dd>Learn what happens when your activity is destroyed and how you can rebuild the activity
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state when necessary.</dd>
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</dl>
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