topics/resources/runtime-changes.jd

page.title=
page.tags=Activity
@jd:body

<div id="qv-wrapper">
<div id="qv">

  <h2></h2>
  <ol>
    <li><a href="#RetainingAnObject"></a></li>
    <li><a href="#HandlingTheChange"></a>
  </ol>

  <h2></h2>
  <ol>
    <li><a href="providing-resources.html"></a></li>
    <li><a href="accessing-resources.html"></a></li>
    <li><a href="http://android-developers.blogspot.com/2009/02/faster-screen-orientation-change.html">
</a></li>
  </ol>
</div>
</div>

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


</p>

<p> <a href="{@docRoot}guide/components/activities.html#Lifecycle">Activity </a> Activity  Android
{@link android.app.Activity#onSaveInstanceState(Bundle) onSaveInstanceState()}  Activity


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

<p> ()


 Activity  <a href="{@docRoot}guide/components/activities.html#Lifecycle">Activity </a></p>

<p>

</p>

<ol type="a">
  <li><a href="#RetainingAnObject"></a>
  <p> Activity  Activity
</p>

  </li>
  <li><a href="#HandlingTheChange"></a>
  <p> Activity Activity

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


<h2 id="RetainingAnObject"></h2>

<p> Activity

 {@link android.os.Bundle}  Activity  {@link android.app.Activity#onSaveInstanceState(Bundle) onSaveInstanceState()} &mdash; ()


 Activity  {@link
android.app.Fragment}  Activity

</p>

<p> Android  Activity  Activity
 Activity
</p>

<p></p>

<ol>
  <li> {@link android.app.Fragment}
</li>
  <li> {@link android.app.Fragment#setRetainInstance(boolean)}
      </li>
  <li> Activity</li>
  <li> Activity  {@link android.app.FragmentManager}
</li>
</ol>

<p></p>

<pre>
public class RetainedFragment extends Fragment {

    // data object we want to retain
    private MyDataObject data;

    // this method is only called once for this fragment
    &#64;Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // retain this fragment
        setRetainInstance(true);
    }

    public void setData(MyDataObject data) {
        this.data = data;
    }

    public MyDataObject getData() {
        return data;
    }
}
</pre>

<p class="caution"><strong></strong> {@link android.app.Activity}  {@link
android.graphics.drawable.Drawable}{@link android.widget.Adapter}{@link android.view.View}  {@link android.content.Context}

 Activity
()

</p>

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

 Activity </p>

<pre>
public class MyActivity extends Activity {

    private RetainedFragment dataFragment;

    &#64;Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // find the retained fragment on activity restarts
        FragmentManager fm = getFragmentManager();
        dataFragment = (DataFragment) fm.findFragmentByTag(data);

        // create the fragment and data the first time
        if (dataFragment == null) {
            // add the fragment
            dataFragment = new DataFragment();
            fm.beginTransaction().add(dataFragment, data).commit();
            // load the data from the web
            dataFragment.setData(loadMyData());
        }

        // the data is available in dataFragment.getData()
        ...
    }

    &#64;Override
    public void onDestroy() {
        super.onDestroy();
        // store the data in the fragment
        dataFragment.setData(collectMyLoadedData());
    }
}
</pre>

<p>{@link android.app.Activity#onCreate(Bundle) onCreate()}  Activity
{@link android.app.Activity#onCreate(Bundle) onCreate()}

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


<h2 id="HandlingTheChange"></h2>

<p><em></em> Activity  Activity  Activity


</p>

<p class="note"><strong></strong>


</p>

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

<a href="{@docRoot}guide/topics/manifest/activity-element.html#config">{@code
android:configChanges}</a>  ( {@code "orientation"} {@code "keyboardHidden"} )

 {@code |}
</p>

<p> Activity
</p>

<pre>
&lt;activity android:name=".MyActivity"
          android:configChanges="orientation|keyboardHidden"
          android:label="@string/app_name">
</pre>

<p> {@code MyActivity}
 {@code MyActivity}  {@link android.app.Activity#onConfigurationChanged(Configuration) onConfigurationChanged()}
 {@link android.content.res.Configuration}

 {@link android.content.res.Configuration}

Activity  {@link android.content.res.Resources}  UI  Activity


</p>

<p class="caution"><strong></strong> Android 3.2 (API  13) <strong></strong>

 API  13  ( <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#min">{@code minSdkVersion}</a>  <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code targetSdkVersion}</a> ){@code
"orientation"}  {@code "screenSize"}

 {@code
android:configChanges="orientation|screenSize"} API  12  Activity  ( Android 3.2  Activity)

</p>

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

<pre>
&#64;Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);

    // Checks the orientation of the screen
    if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
        Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
    } else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT){
        Toast.makeText(this, "portrait", Toast.LENGTH_SHORT).show();
    }
}
</pre>

<p>{@link android.content.res.Configuration}


 {@link
android.content.res.Resources}  {@link android.widget.ImageView#setImageResource(int)
setImageResource()}  {@link android.widget.ImageView} (<a href="providing-resources.html#AlternateResources"></a>)

</p>

<p>{@link
android.content.res.Configuration}  {@link android.content.res.Configuration}
 {@link
android.content.res.Configuration}
</p>

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

</p>

<p><em></em> {@link
android.app.Activity#onConfigurationChanged(Configuration) onConfigurationChanged()}
 Activity

 Activity


</p>

<p> Activity  <a href="{@docRoot}guide/topics/manifest/activity-element.html#config">{@code
android:configChanges}</a>  {@link android.content.res.Configuration}
</p>