guide/components/processes-and-threads.jd

page.title=
page.tags=

@jd:body

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

<h2></h2>
<ol>
<li><a href="#Processes"></a>
  <ol>
    <li><a href="#Lifecycle"></a></li>
  </ol>
</li>
<li><a href="#Threads"></a>
  <ol>
    <li><a href="#WorkerThreads"></a></li>
    <li><a href="#ThreadSafe"></a></li>
  </ol>
</li>
<li><a href="#IPC"></a></li>
</ol>

</div>
</div>

<p>Android  Linux

 ()
 ()


</p>

<p> Android </p>


<h2 id="Processes"></h2>

<p>

</p>

<p> &mdash; <a href="{@docRoot}guide/topics/manifest/activity-element.html">{@code
&lt;activity&gt;}</a><a href="{@docRoot}guide/topics/manifest/service-element.html">{@code
&lt;service&gt;}</a><a href="{@docRoot}guide/topics/manifest/receiver-element.html">{@code
&lt;receiver&gt;}</a>  <a href="{@docRoot}guide/topics/manifest/provider-element.html">{@code
&lt;provider&gt;}</a> &mdash;  {@code android:process}


{@code android:process} Linux  ID

</p>

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

<p>Android


</p>

<p>Android
 Activity  Activity


 </p>


<h3 id="Lifecycle"></h3>

<p>Android


</p>

<p> (<em></em><em></em>)

</p>

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

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

        <li> {@link android.app.Service}  Activity
</li>

        <li> {@link android.app.Service}  ( {@link android.app.Service#startForeground startForeground()})


        <li> {@link android.app.Service}  ({@link android.app.Service#onCreate onCreate()}{@link android.app.Service#onStart onStart()}  {@link android.app.Service#onDestroy onDestroy()})

</li>

        <li> {@link android.content.BroadcastReceiver}  {@link
android.content.BroadcastReceiver#onReceive onReceive()} </li>
    </ul>

    <p>


</p></li>

  <li><b></b>
    <p>

</p>

      <ul>
        <li> {@link android.app.Activity}  ( {@link android.app.Activity#onPause onPause()} )
 Activity  Activity

</li>

        <li> {@link android.app.Service}  () Activity
</li>
      </ul>

      <p>
 </p>
    </li>

  <li><b></b>
    <p> {@link
android.content.Context#startService startService()}
 ()


 </p>
  </li>

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


 LRU ()  Activity

 Activity  Activity  Activity


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

  <li><b></b>
    <p>


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


  <p>Android
 Activity
</p>

  <p>

 A  B  A  B  A  B

</p>

  <p> Activity  Activity <a href="{@docRoot}guide/components/services.html"></a> &mdash;  Activity  Activity  Activity Activity


</p>


<h2 id="Threads"></h2>

<p>

 Android UI  ({@link
android.widget}  {@link android.view} )
 UI
</p>

<p><em></em> UI

 ( {@link android.view.View#onKeyDown onKeyDown()} )  UI

</p>

<p> UI

UI
</p>

<p>
 UI  UI ()


 UI  ( 5 )<a href="http://developer.android.com/guide/practices/responsiveness.html"></a>(ANR)


</p>

<p>Andoid UI <em></em> UI &mdash;  UI

Android </p>

<ol>
<li> UI
<li> UI  Android UI
</ol>

<h3 id="WorkerThreads"></h3>

<p> UI  UI
 ()

</p>

<p> {@link android.widget.ImageView}
</p>

<pre>
public void onClick(View v) {
    new Thread(new Runnable() {
        public void run() {
            Bitmap b = loadImageFromNetwork("http://example.com/image.png");
            mImageView.setImageBitmap(b);
        }
    }).start();
}
</pre>

<p>
 UI  Android UI <em></em>&mdash;  {@link
android.widget.ImageView} UI

</p>

<p>Android  UI
</p>

<ul>
<li>{@link android.app.Activity#runOnUiThread(java.lang.Runnable)
Activity.runOnUiThread(Runnable)}</li>
<li>{@link android.view.View#post(java.lang.Runnable) View.post(Runnable)}</li>
<li>{@link android.view.View#postDelayed(java.lang.Runnable, long) View.postDelayed(Runnable,
long)}</li>
</ul>

<p> {@link
android.view.View#post(java.lang.Runnable) View.post(Runnable)} </p>

<pre>
public void onClick(View v) {
    new Thread(new Runnable() {
        public void run() {
            final Bitmap bitmap = loadImageFromNetwork("http://example.com/image.png");
            mImageView.post(new Runnable() {
                public void run() {
                    mImageView.setImageBitmap(bitmap);
                }
            });
        }
    }).start();
}
</pre>

<p> UI  {@link android.widget.ImageView}
</p>

<p>
 {@link android.os.Handler} UI

 {@link android.os.AsyncTask}  UI
</p>


<h4 id="AsyncTask"> AsyncTask</h4>

<p>{@link android.os.AsyncTask}
 UI /
</p>

<p> {@link android.os.AsyncTask} {@link
android.os.AsyncTask#doInBackground doInBackground()}
 UI {@link
android.os.AsyncTask#onPostExecute onPostExecute()}  {@link
android.os.AsyncTask#doInBackground doInBackground()}  UI  UI
 UI  {@link android.os.AsyncTask#execute execute()}
</p>

<p> {@link android.os.AsyncTask}
</p>

<pre>
public void onClick(View v) {
    new DownloadImageTask().execute("http://example.com/image.png");
}

private class DownloadImageTask extends AsyncTask&lt;String, Void, Bitmap&gt; {
    /** The system calls this to perform work in a worker thread and
      * delivers it the parameters given to AsyncTask.execute() */
    protected Bitmap doInBackground(String... urls) {
        return loadImageFromNetwork(urls[0]);
    }

    /** The system calls this to perform work in the UI thread and delivers
      * the result from doInBackground() */
    protected void onPostExecute(Bitmap result) {
        mImageView.setImageBitmap(result);
    }
}
</pre>

<p> UI  UI
</p>

<p> {@link android.os.AsyncTask}
</p>

<ul>
<li>
</li>
<li>{@link android.os.AsyncTask#doInBackground doInBackground()}
</li>
<li>{@link android.os.AsyncTask#onPreExecute onPreExecute()}{@link
android.os.AsyncTask#onPostExecute onPostExecute()}  {@link
android.os.AsyncTask#onProgressUpdate onProgressUpdate()}  UI </li>
<li>{@link android.os.AsyncTask#doInBackground doInBackground()}
{@link android.os.AsyncTask#onPostExecute onPostExecute()}</li>
<li> {@link
android.os.AsyncTask#doInBackground doInBackground()}  {@link android.os.AsyncTask#publishProgress publishProgress()} UI  {@link
android.os.AsyncTask#onProgressUpdate onProgressUpdate()}</li>
<li></li>
</ul>

<p class="caution"><strong></strong><a href="{@docRoot}guide/topics/resources/runtime-changes.html"></a> ()  Activity

 <a href="http://code.google.com/p/shelves/">Shelves</a>  Activity

</p>


<h3 id="ThreadSafe"></h3>

<p>
 </p>

<p><a href="{@docRoot}guide/components/bound-services.html"></a> {@link android.os.IBinder IBinder}  {@link android.os.IBinder}


 {@link android.os.IBinder
IBinder} ( UI )
{@link android.app.Service#onBind onBind()}  UI  {@link android.app.Service#onBind
onBind()}


{@link android.os.IBinder IBinder}  {@link android.os.IBinder
IBinder} </p>

<p>
 {@link android.content.ContentResolver}  {@link android.content.ContentProvider}
 {@link
android.content.ContentProvider}  &mdash; {@link
android.content.ContentProvider#query query()}{@link android.content.ContentProvider#insert
insert()}{@link android.content.ContentProvider#delete delete()}{@link
android.content.ContentProvider#update update()}  {@link android.content.ContentProvider#getType
getType()} &mdash;  UI

 </p>


<h2 id="IPC"></h2>

<p>Android  (RPC)  (IPC) RPC  ()  Activity


Android  IPC  RPC
 </p>

<p> IPC {@link
android.content.Context#bindService bindService()} <a href="{@docRoot}guide/components/services.html"></a></p>


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

<p>For information about how to perform work in the background for an indefinite period of time
(without a user interface), continue with the <b><a
href="{@docRoot}guide/components/services.html">Services</a></b> document.</p>
-->