guide/components/activities.jd

page.title=
page.tags=activity,intent
@jd:body

<div id="qv-wrapper">
<div id="qv">
<h2>  </h2>
<ol>
  <li><a href="#Creating"> </a>
    <ol>
      <li><a href="#UI">  </a></li>
      <li><a href="#Declaring">  </a></li>
    </ol>
  </li>
  <li><a href="#StartingAnActivity"> </a>
    <ol>
      <li><a href="#StartingAnActivityForResult">   </a></li>
    </ol>
  </li>
  <li><a href="#ShuttingDown"> </a></li>
  <li><a href="#Lifecycle">   </a>
    <ol>
      <li><a href="#ImplementingLifecycleCallbacks">   </a></li>
      <li><a href="#SavingActivityState">  </a></li>
      <li><a href="#ConfigurationChanges">  </a></li>
      <li><a href="#CoordinatingActivities"> </a></li>
    </ol>
  </li>
</ol>

<h2>Key </h2>
<ol>
  <li>{@link android.app.Activity}</li>
</ol>

<h2> </h2>
<ol>
  <li><a href="{@docRoot}guide/components/tasks-and-back-stack.html">
</a></li>
</ol>

</div>
</div>


<p>{@link android.app.Activity}    ,
       ,  ,
.          .
   ,
.</p>

<p>
.       ""  ,
         .
            .

(" ") .   ,
 .    ""  ,
    <em></em>
 ()    (
<a href="{@docRoot}guide/components/tasks-and-back-stack.html">
  </a>   ).</p>

<p>       ,
      .
   , , ,             .

          .

    .  ,
      .
    .</p>

<p>                    ,

.</p>


<h2 id="Creating"> </h2>

<p>  {@link android.app.Activity}  (
  )  .
 , , ,
             .
 .</p>

<dl>
  <dt>{@link android.app.Activity#onCreate onCreate()}</dt>
  <dd>    .      .

.
      ,   {@link android.app.Activity#setContentView
    setContentView()}         .</dd>
  <dt>{@link android.app.Activity#onPause onPause()}</dt>
  <dd>
  (       ).
        (
    ).</dd>
</dl>

<p>      ,

    .
<a href="#Lifecycle">   </a>    .</p>


<h3 id="UI">  </h3>

<p>       &mdash;,
{@link android.view.View}    .
       .  ,
    .</p>

<p>Android
. ""  ( )   .
,  ,      . ""  ,  ,           {@link
android.view.ViewGroup}
. , {@link android.view.View}
{@link android.view.ViewGroup} (   )
     .</p>

<p>
XML    .
        .
{@link android.app.Activity#setContentView(int) setContentView()}  UI  ,
   ID   .     {@link android.view.View}
  {@link
android.view.View} {@link android.view.ViewGroup}
{@link android.view.ViewGroup} {@link android.app.Activity#setContentView(View)
setContentView()}      .</p>

<p>     <a href="{@docRoot}guide/topics/ui/index.html"> </a>  .</p>


<h3 id="Declaring">  </h3>

<p>
 .      <a href="{@docRoot}guide/topics/manifest/activity-element.html">{@code &lt;activity&gt;}</a>
 <a href="{@docRoot}guide/topics/manifest/application-element.html">{@code &lt;application&gt;}</a>
   . :</p>

<pre>
&lt;manifest ... &gt;
  &lt;application ... &gt;
      &lt;activity android:name=".ExampleActivity" /&gt;
      ...
  &lt;/application ... &gt;
  ...
&lt;/manifest &gt;
</pre>

<p> ,     UI
        .
 <a href="{@docRoot}guide/topics/manifest/activity-element.html#nm">{@code android:name}</a>
    .     .
        .
         (  <a href="http://android-developers.blogspot.com/2011/06/things-that-cannot-change.html">
</a> ).</p>

<p>       <a href="{@docRoot}guide/topics/manifest/activity-element.html">{@code &lt;activity&gt;}</a>
   .</p>


<h4>  </h4>

<p><a href="{@docRoot}guide/topics/manifest/activity-element.html">{@code
&lt;activity&gt;}</a>         .          <a href="{@docRoot}guide/topics/manifest/intent-filter-element.html">{@code
&lt;intent-filter&gt;}</a>
.</p>

<p>Android SDK      ,
         ""
  ,  " "   .
  .</p>

<pre>
&lt;activity android:name=".ExampleActivity" android:icon="@drawable/app_icon"&gt;
    &lt;intent-filter&gt;
        &lt;action android:name="android.intent.action.MAIN" /&gt;
        &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
    &lt;/intent-filter&gt;
&lt;/activity&gt;
</pre>

<p><a href="{@docRoot}guide/topics/manifest/action-element.html">{@code
&lt;action&gt;}</a>     ""    . <a href="{@docRoot}guide/topics/manifest/category-element.html">{@code
&lt;category&gt;}</a>
       (      ).</p>

<p>
     ,      . ""  " "
  (  ).
          .
        (    ).</p>

<p>,   (  )

.
<a href="{@docRoot}guide/topics/manifest/action-element.html">{@code
&lt;action&gt;}</a>   <a href="{@docRoot}guide/topics/manifest/intent-filter-element.html">{@code
&lt;intent-filter&gt;}</a>   ,   <a href="{@docRoot}guide/topics/manifest/category-element.html">{@code
&lt;category&gt;}</a>  / <a href="{@docRoot}guide/topics/manifest/data-element.html">{@code
&lt;data&gt;}</a>    .
.</p>

<p>       <a href="{@docRoot}guide/components/intents-filters.html">   </a>
 .</p>


<h2 id="StartingAnActivity"> </h2>

<p>   {@link android.app.Activity#startActivity
 startActivity()}        {@link android.content.Intent}
 .      ,
  (   ,

      ).
   .</p>

<p>    ,       .

  .  ,    {@code
SignInActivity}     .</p>

<pre>
Intent intent = new Intent(this, SignInActivity.class);
startActivity(intent);
</pre>

<p>,         .    ,
          .  ,
       .
        .
  .

    .
        ,     .
        ,
 .</p>

<pre>
Intent intent = new Intent(Intent.ACTION_SEND);
intent.putExtra(Intent.EXTRA_EMAIL, recipientArray);
startActivity(intent);
</pre>

<p>  {@link android.content.Intent#EXTRA_EMAIL}
  .
,
 ""  .
      .</p>


<h3 id="StartingAnActivityForResult">   </h3>

<p>       .  ,
 ({@link android.app.Activity#startActivity
 startActivity()} ) {@link android.app.Activity#startActivityForResult
 startActivityForResult()}   .
, {@link android.app.Activity#onActivityResult onActivityResult()}
  .    ,  {@link
android.content.Intent}   {@link android.app.Activity#onActivityResult onActivityResult()}
  .</p>

<p>            .
           .
   .</p>

<pre>
private void pickContact() {
    // Create an intent to "pick" a contact, as defined by the content provider URI
    Intent intent = new Intent(Intent.ACTION_PICK, Contacts.CONTENT_URI);
    startActivityForResult(intent, PICK_CONTACT_REQUEST);
}

&#64;Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    // If the request went well (OK) and the request was PICK_CONTACT_REQUEST
    if (resultCode == Activity.RESULT_OK &amp;&amp; requestCode == PICK_CONTACT_REQUEST) {
        // Perform a query to the contact's content provider for the contact's name
        Cursor cursor = getContentResolver().query(data.getData(),
        new String[] {Contacts.DISPLAY_NAME}, null, null, null);
        if (cursor.moveToFirst()) { // True if the cursor is not empty
            int columnIndex = cursor.getColumnIndex(Contacts.DISPLAY_NAME);
            String name = cursor.getString(columnIndex);
            // Do something with the selected contact's name...
        }
    }
}
</pre>

<p>      {@link
android.app.Activity#onActivityResult onActivityResult()}
  .      .
{@code resultCode} {@link android.app.Activity#RESULT_OK} . ,
  .   {@code requestCode}
{@link android.app.Activity#startActivityForResult
startActivityForResult()}      .
{@link android.content.Intent}({@code data} )      .</p>

<p> {@link
android.content.ContentResolver}     ,
{@link android.database.Cursor} .
<a href="{@docRoot}guide/topics/providers/content-providers.html"> </a>  .</p>

<p>     <a href="{@docRoot}guide/components/intents-filters.html">
 </a> .</p>


<h2 id="ShuttingDown"> </h2>

<p>    {@link android.app.Activity#finish
finish()}   .
{@link android.app.Activity#finishActivity finishActivity()}        .</p>

<p class="note"><strong>:</strong>  ,
  .         ,
Android
 .
     ,
 .</p>


<h2 id="Lifecycle">   </h2>

<p>

   .      ,
       .</p>

<p>       .</p>

<dl>
  <dt><i></i></dt>
    <dd>        (
" "  ).</dd>

  <dt><i></i></dt>
    <dd>        ,     .  ,

     .    ({@link android.app.Activity}
   ,      ,
     ),        .</dd>

  <dt><i></i></dt>
    <dd>      (
"" ).      ({@link android.app.Activity}
   ,          <em></em>
). ,
       .</dd>
</dl>

<p>    ,      .
 ({@link android.app.Activity#finish finish()}  )
.     (   )
.</p>


<h3 id="ImplementingLifecycleCallbacks">   </h3>

<p>         ,
     .    ,
           .
        .</p>


<pre>
public class ExampleActivity extends Activity {
    &#64;Override
    public void {@link android.app.Activity#onCreate onCreate}(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // The activity is being created.
    }
    &#64;Override
    protected void {@link android.app.Activity#onStart onStart()} {
        super.onStart();
        // The activity is about to become visible.
    }
    &#64;Override
    protected void {@link android.app.Activity#onResume onResume()} {
        super.onResume();
        // The activity has become visible (it is now "resumed").
    }
    &#64;Override
    protected void {@link android.app.Activity#onPause onPause()} {
        super.onPause();
        // Another activity is taking focus (this activity is about to be "paused").
    }
    &#64;Override
    protected void {@link android.app.Activity#onStop onStop()} {
        super.onStop();
        // The activity is no longer visible (it is now "stopped")
    }
    &#64;Override
    protected void {@link android.app.Activity#onDestroy onDestroy()} {
        super.onDestroy();
        // The activity is about to be destroyed.
    }
}
</pre>

<p class="note"><strong>:</strong>      ,
         (  ).</p>

<p>          .
          . </p>

<ul>
<li>  <b> </b> {@link
android.app.Activity#onCreate onCreate()}  {@link
android.app.Activity#onDestroy}   .  {@link android.app.Activity#onCreate onCreate()}
"" (  )
 {@link android.app.Activity#onDestroy}  .  ,
          ,
  {@link android.app.Activity#onCreate onCreate()}   {@link
android.app.Activity#onDestroy}     .</li>

<li><p> <b> </b> {@link
android.app.Activity#onStart onStart()}  {@link
android.app.Activity#onStop onStop()}   .
  .  {@link android.app.Activity#onStop onStop()}
          .
       .  ,
{@link
android.app.Activity#onStart onStart()} {@link android.content.BroadcastReceiver}  UI
{@link android.app.Activity#onStop onStop()}
 .      {@link android.app.Activity#onStart onStart()}  {@link
android.app.Activity#onStop onStop()}     ,
      .</p></li>

<li><p> <b> </b> {@link
android.app.Activity#onResume onResume()}  {@link android.app.Activity#onPause
onPause()}   .
 .          .
,
 {@link android.app.Activity#onPause onPause()} .      ,
  .          .</p></li>
</ul>

<p> 1            .

     . <p>

<img src="{@docRoot}images/activity_lifecycle.png" alt="" />
<p class="img-caption"><strong> 1.</strong>   .</p>

<p>      1  ,

       .
       .</p>

<p class="table-caption"><strong> 1.</strong>
  .</p>

<table border="2" width="85%" frame="hsides" rules="rows">
<colgroup align="left" span="3"></colgroup>
<colgroup align="left"></colgroup>
<colgroup align="center"></colgroup>
<colgroup align="center"></colgroup>

<thead>
<tr><th colspan="3"></th> <th></th> <th>   ?</th> <th></th></tr>
</thead>

<tbody>
<tr>
  <td colspan="3" align="left"><code>{@link android.app.Activity#onCreate onCreate()}</code></td>
  <td>    .
            .
  ,     .

  (    <a href="#actstate">  </a>
).
      <p>   {@code onStart()} .</p></td>
  <td align="center"></td>
      <td align="center">{@code onStart()}</td>
</tr>

<tr>
   <td rowspan="5" style="border-left: none; border-right: none;">&nbsp;&nbsp;&nbsp;&nbsp;</td>
   <td colspan="2" align="left"><code>{@link android.app.Activity#onRestart
onRestart()}</code></td>
   <td>
.
       <p>   {@code onStart()} .</p></td>
   <td align="center"></td>
   <td align="center">{@code onStart()}</td>
</tr>

<tr>
   <td colspan="2" align="left"><code>{@link android.app.Activity#onStart onStart()}</code></td>
   <td>    .
       <p>   {@code onResume()}  ,
  {@code onStop()}  .</p></td>
    <td align="center"></td>
    <td align="center">{@code onResume()} <br/><br/> {@code onStop()}</td>
</tr>

<tr>
   <td rowspan="2" style="border-left: none;">&nbsp;&nbsp;&nbsp;&nbsp;</td>
   <td align="left"><code>{@link android.app.Activity#onResume onResume()}</code></td>
   <td>
.
   ,    .
       <p>   {@code onPause()} .</p></td>
   <td align="center"></td>
   <td align="center">{@code onPause()}</td>
</tr>

<tr>
   <td align="left"><code>{@link android.app.Activity#onPause onPause()}</code></td>
   <td>
.
 ,   CPU
   .          .
       .
       <p>    {@code onResume()}
    {@code onStop()}  .
</td>
   <td align="center"><strong style="color:#800000"></strong></td>
   <td align="center">{@code onResume()} <br/><br/> {@code onStop()}</td>
</tr>

<tr>
   <td colspan="2" align="left"><code>{@link android.app.Activity#onStop onStop()}</code></td>
   <td>       .
       ,
(   )       .
       <p>
{@code onRestart()}
{@code onDestroy()}  .</p></td>
   <td align="center"><strong style="color:#800000"></strong></td>
   <td align="center">{@code onRestart()} <br/><br/> {@code onDestroy()}</td>
</tr>

<tr>
   <td colspan="3" align="left"><code>{@link android.app.Activity#onDestroy
onDestroy()}</code></td>
   <td>   .
 .
 (  <code>{@link android.app.Activity#finish
       finish()}</code> )  ,
   .
   <code>{@link
       android.app.Activity#isFinishing isFinishing()}</code>    .</td>
   <td align="center"><strong style="color:#800000"></strong></td>
   <td align="center"><em></em></td>
</tr>
</tbody>
</table>

<p>"   ?"
  <em>  </em>
         .      ""  ({@link
android.app.Activity#onPause
onPause()}, {@link android.app.Activity#onStop onStop()}  {@link android.app.Activity#onDestroy
onDestroy()}). {@link android.app.Activity#onPause onPause()}
 ,   {@link android.app.Activity#onPause onPause()}  <em> </em>
   .
      , {@link
android.app.Activity#onStop onStop()} {@link android.app.Activity#onDestroy onDestroy()}
   . ,   (  )     {@link android.app.Activity#onPause onPause()}
. , {@link android.app.Activity#onPause onPause()}
      .

.</p>

<p> <b> </b>  ""
     .
{@link android.app.Activity#onPause onPause()}
{@link android.app.Activity#onResume onResume()}      .
{@link android.app.Activity#onPause onPause()}    . </p>

<p class="note"><strong>:</strong>  1
   " "       .
  .
 <a href="{@docRoot}guide/components/processes-and-threads.html">
 </a>    .</p>


<h3 id="SavingActivityState">  </h3>

<p><a href="#Lifecycle">   </a>

        .
{@link android.app.Activity}
     .             . ,

 ("" )       .</p>

<p>        {@link
android.app.Activity}
. ,        {@link android.app.Activity}
  . ,
      .
      .

{@link
android.app.Activity#onSaveInstanceState onSaveInstanceState()}         .</p>

<p> {@link android.app.Activity#onSaveInstanceState onSaveInstanceState()}
      .  {@link
android.os.Bundle#putString putString()} {@link
android.os.Bundle#putInt putInt()}   ,
   -     {@link android.os.Bundle} .

   ,
{@link android.os.Bundle} {@link android.app.Activity#onCreate onCreate()} {@link
android.app.Activity#onRestoreInstanceState onRestoreInstanceState()} .
  {@link android.os.Bundle}
   .     ,   {@link
android.os.Bundle} null(
).</p>

<img src="{@docRoot}images/fundamentals/restore_instance.png" alt="" />
<p class="img-caption"><strong> 2.</strong>
       .
     ,
    .</p>

<p class="note"><strong>:</strong>          {@link
android.app.Activity#onSaveInstanceState onSaveInstanceState()}

(

   <em></em>       ).  {@link android.app.Activity#onSaveInstanceState
onSaveInstanceState()}  , {@link
android.app.Activity#onStop onStop()}     {@link android.app.Activity#onPause
onPause()}    .</p>

<p>    {@link
android.app.Activity#onSaveInstanceState onSaveInstanceState()}  ,
{@link android.app.Activity}    {@link
android.app.Activity#onSaveInstanceState onSaveInstanceState()}    . ,
  {@link
android.view.View}    {@link
android.view.View#onSaveInstanceState onSaveInstanceState()}  ,
 . Android
  , UI
 .  , {@link android.widget.EditText}
  {@link android.widget.CheckBox}    .
            ID(<a href="{@docRoot}guide/topics/resources/layout-resource.html#idvalue">{@code android:id}</a>
 )  .  ID
  .</p>

<div class="sidebox-wrapper">
<div class="sidebox">
<p>,
{@link android.R.attr#saveEnabled android:saveEnabled}  {@code "false"}
{@link android.view.View#setSaveEnabled setSaveEnabled()}           .
 ,  UI         .</p>
</div>
</div>

<p>{@link
android.app.Activity#onSaveInstanceState onSaveInstanceState()}    UI
       .
 ,         (
UI        UI
).</p>

<p>{@link
android.app.Activity#onSaveInstanceState onSaveInstanceState()}   UI      ,

   {@link android.app.Activity#onSaveInstanceState onSaveInstanceState()}
  .   {@link
android.app.Activity#onRestoreInstanceState onRestoreInstanceState()}  ,      .
        .</p>

<p class="note"><strong>:</strong> {@link android.app.Activity#onSaveInstanceState
onSaveInstanceState()}
    (UI
)   ,       .  ,      (
  )  {@link
android.app.Activity#onPause onPause()}  .</p>

<p>
  .

 .
       .
  .</p>


<h3 id="ConfigurationChanges">  </h3>

<p>       (:  ,
   ).    Android
( {@link android.app.Activity#onDestroy}   {@link
android.app.Activity#onCreate onCreate()} ).


(:       ).</p>

<p>
        ,
        .</p>

<p>
{@link
 android.app.Activity#onSaveInstanceState onSaveInstanceState()} {@link
android.app.Activity#onRestoreInstanceState onRestoreInstanceState()}( {@link
android.app.Activity#onCreate onCreate()})      .</p>

<p>
<a href="{@docRoot}guide/topics/resources/runtime-changes.html">
</a>   .</p>


<h3 id="CoordinatingActivities"> </h3>

 <p>    ,      .
  (     ),
 .           ,
              .
,            .
</p>

<p>
           .   A
 B     . </p>

<ol>
<li> A {@link android.app.Activity#onPause onPause()}  .</li>

<li> B {@link android.app.Activity#onCreate onCreate()}, {@link
android.app.Activity#onStart onStart()}, {@link android.app.Activity#onResume onResume()}
   (   B  ).</li>

<li> ,  A         {@link
android.app.Activity#onStop onStop()}  .</li>
</ol>

 <p>
    .
         ,
{@link android.app.Activity#onPause onPause()} ({@link
android.app.Activity#onStop onStop()}  )    .</p>

<!--
<h2>Beginner's Path</h2>

<p>For more information about how Android maintains a history of activities and
enables user multitasking, continue with the <b><a
href="{@docRoot}guide/components/tasks-and-back-stack.html">Tasks and Back
Stack</a></b> document.</p>
-->