guide/components/loaders.jd

page.title=Trnh ti
parent.title=Hot ng
parent.link=activities.html
@jd:body
<div id="qv-wrapper">
<div id="qv">
    <h2>Trong ti liu ny</h2>
    <ol>
    <li><a href="#summary">Tng quan v API Trnh ti</a></li>
    <li><a href="#app">S dng cc Trnh ti trong mt ng dng</a>
      <ol>
        <li><a href="#requirements"></a></li>
        <li><a href="#starting">Khi ng mt Trnh ti</a></li>
        <li><a href="#restarting">Khi ng li mt Trnh ti</a></li>
        <li><a href="#callback">S dng cc Phng php Gi li LoaderManager</a></li>
      </ol>
    </li>
    <li><a href="#example">V d</a>
       <ol>
         <li><a href="#more_examples">Thm V d</a></li>
        </ol>
    </li>
  </ol>

  <h2>Lp kha</h2>
    <ol>
      <li>{@link android.app.LoaderManager}</li>
      <li>{@link android.content.Loader}</li>

    </ol>

    <h2>Cc mu lin quan</h2>
   <ol>
     <li> <a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/LoaderCursor.html">
LoaderCursor</a></li>
     <li> <a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/LoaderThrottle.html">
LoaderThrottle</a></li>
   </ol>
  </div>
</div>

<p>c gii thiu trong Android 3.0, trnh ti gip vic ti d liu khng ng b
trong mt hot ng hoc phn on tr nn d dng. Trnh ti c nhng c im sau:</p>
  <ul>
    <li>Chng sn c cho mi {@link android.app.Activity} v {@link
android.app.Fragment}.</li>
    <li>Chng cung cp kh nng ti d liu khng ng b.</li>
    <li>Chng theo di ngun d liu ca mnh v chuyn giao kt qu mi khi ni dung
thay i.</li>
    <li>Chng t ng kt ni li vi con chy ca trnh ti cui cng khi c
to li sau khi cu hnh thay i. V th, chng khng cn truy vn li d liu
ca mnh.</li>
  </ul>

<h2 id="summary">Tng quan v API Trnh ti</h2>

<p>C nhiu lp v giao din c th c lin quan trong khi s dng
cc trnh ti trong mt ng dng. Chng c tm tt trong bng ny.</p>

<table>
  <tr>
    <th>Lp/Giao din</th>
    <th>M t</th>
  </tr>
  <tr>
    <td>{@link android.app.LoaderManager}</td>
    <td>Mt lp tm tt c lin kt vi {@link android.app.Activity} hoc
{@link android.app.Fragment}  qun l mt hoc nhiu thc th {@link
android.content.Loader}.N gip ng dng qun l
cc thao tc chy lu hn cng vi vng i {@link android.app.Activity}
hoc {@link android.app.Fragment}; cng dng ph bin nht ca lp ny l khi dng vi
{@link android.content.CursorLoader}, tuy nhin, cc ng dng c t do ghi
trnh ti ca chnh mnh  ti cc kiu d liu khc.
    <br />
    <br />
    Ch c mt {@link android.app.LoaderManager} trn mi hot ng hoc phn on. Nhng mt {@link android.app.LoaderManager} c th c
nhiu trnh ti.</td>
  </tr>
  <tr>
    <td>{@link android.app.LoaderManager.LoaderCallbacks}</td>
    <td>Mt giao din gi li  mt my khch tng tc vi {@link
android.app.LoaderManager}. V d, bn s dng phng php gi li {@link
android.app.LoaderManager.LoaderCallbacks#onCreateLoader onCreateLoader()}
 to mt trnh ti mi.</td>
  </tr>
  <tr>
    <td>{@link android.content.Loader}</td>
    <td>Mt lp tm tt c vai tr thc hin vic ti d liu khng ng b. y l
lp c bn cho mt trnh ti. Thng thng, bn s s dng {@link
android.content.CursorLoader}, nhng bn c th trin khai lp con ca chnh mnh. Trong khi
cc trnh ti ang hot ng, chng s theo di ngun d liu ca mnh v chuyn giao
kt qu mi khi ni dung thay i. </td>
  </tr>
  <tr>
    <td>{@link android.content.AsyncTaskLoader}</td>
    <td>Trnh ti tm tt c chc nng cung cp {@link android.os.AsyncTask}  thc hin cng vic.</td>
  </tr>
  <tr>
    <td>{@link android.content.CursorLoader}</td>
    <td>Mt lp con ca {@link android.content.AsyncTaskLoader} c chc nng truy vn
{@link android.content.ContentResolver} v tr v mt {@link
android.database.Cursor}. Lp ny trin khai giao thc {@link
android.content.Loader} theo mt cch chun ha  truy vn cc con chy,
xy dng trn {@link android.content.AsyncTaskLoader}  thc hin truy vn con chy
trn mt lung nn sao cho n khng chn UI ca ng dng. S dng
trnh ti ny l cch tt nht  ti d liu khng ng b t mt {@link
android.content.ContentProvider}, thay v phi thc hin mt truy vn c qun l thng qua
phn on hoc cc API ca hot ng.</td>
  </tr>
</table>

<p>Cc lp v giao din trong bng trn l nhng thnh phn thit yu
m bn s s dng  trin khai mt trnh ti trong ng dng ca mnh. Bn s khng cn tt c chng
cho tng trnh ti m bn to lp, nhng bn s lun cn mt tham chiu ti {@link
android.app.LoaderManager}  khi to mt trnh ti v trin khai
mt lp {@link android.content.Loader} chng hn nh {@link
android.content.CursorLoader}. Cc phn sau y trnh by vi bn cch s dng nhng
lp v giao din ny trong mt ng dng.</p>

<h2 id ="app">S dng cc Trnh ti trong mt ng dng</h2>
<p>Phn ny m t cch s dng cc trnh ti trong mt ng dng Android. Mt
ng dng s dng trnh ti thng bao gm:</p>
<ul>
  <li>Mt {@link android.app.Activity} hoc {@link android.app.Fragment}.</li>
  <li>Mt thc th ca {@link android.app.LoaderManager}.</li>
  <li>Mt {@link android.content.CursorLoader}  ti d liu c d phng bi mt {@link
android.content.ContentProvider}. Hoc cch khc, bn c th trin khai lp con
ca {@link android.content.Loader} hoc {@link android.content.AsyncTaskLoader} ca chnh mnh  ti
d liu t mt s ngun khc.</li>
  <li>Mt trin khai cho {@link android.app.LoaderManager.LoaderCallbacks}.
y l ni bn to trnh ti mi v qun l cc tham chiu ca mnh ti cc
trnh ti hin c.</li>
<li>Mt cch  hin th d liu ca trnh ti, chng hn nh {@link
android.widget.SimpleCursorAdapter}.</li>
  <li>Mt ngun d liu, chng hn nh mt {@link android.content.ContentProvider}, khi s dng mt
{@link android.content.CursorLoader}.</li>
</ul>
<h3 id="starting">Khi ng mt Trnh ti</h3>

<p>{@link android.app.LoaderManager} qun l mt hoc nhiu thc th {@link
android.content.Loader} trong mt {@link android.app.Activity} hoc
{@link android.app.Fragment}. Ch c mt {@link
android.app.LoaderManager} trn mi hot ng hoc phn on.</p>

<p>Thng thng, bn
s khi to mt {@link android.content.Loader} bn trong phng php {@link
android.app.Activity#onCreate onCreate()} ca hot ng, hoc trong phng php
{@link android.app.Fragment#onActivityCreated onActivityCreated()} ca phn on. Bn
lm iu ny nh sau:</p>

<pre>// Prepare the loader.  Either re-connect with an existing one,
// or start a new one.
getLoaderManager().initLoader(0, null, this);</pre>

<p>Phng php {@link android.app.LoaderManager#initLoader initLoader()} s ly nhng
tham s sau:</p>
<ul>
  <li>Mt ID duy nht xc nh trnh ti. Trong v d ny, ID l 0.</li>
<li>Cc tham i ty chn  cung cp cho trnh ti khi
xy dng (<code>null</code> trong v d ny).</li>

<li>Trin khai {@link android.app.LoaderManager.LoaderCallbacks}, phng php m
{@link android.app.LoaderManager} gi  bo co cc s kin trnh ti. Trong v d ny
, lp cuc b trin khai giao din {@link
android.app.LoaderManager.LoaderCallbacks}, v th n chuyn mt tham chiu
ti chnh n, {@code this}.</li>
</ul>
<p>Lnh gi {@link android.app.LoaderManager#initLoader initLoader()} m bo rng mt trnh ti
c khi to v hin hot. N c hai kt qu c th xy ra:</p>
<ul>
  <li>Nu trnh ti c quy nh bi ID  tn ti, trnh ti c to lp cui cng
s c s dng li.</li>
  <li>Nu trnh ti c quy nh bi ID <em>khng</em> tn ti,
{@link android.app.LoaderManager#initLoader initLoader()} s kch khi phng php
{@link android.app.LoaderManager.LoaderCallbacks}{@link android.app.LoaderManager.LoaderCallbacks#onCreateLoader onCreateLoader()}.
y l ni bn trin khai m  khi to v tr v mt trnh ti mi.
 bn thm, hy xem phn <a href="#onCreateLoader">onCreateLoader</a>.</li>
</ul>
<p>D trong trng hp no, trin khai {@link android.app.LoaderManager.LoaderCallbacks}
 cho c lin kt vi trnh ti, v s c gi khi
trng thi ca trnh ti thay i.  Nu ti im thc hin lnh gi ny, hm gi ang trong trng thi
c khi ng ca n, v trnh ti c yu cu  tn ti v  khi to
d liu ca n, khi  h thng s gi {@link
android.app.LoaderManager.LoaderCallbacks#onLoadFinished onLoadFinished()}
ngay lp tc (trong khi {@link android.app.LoaderManager#initLoader initLoader()}),
v th bn phi sn sng khi iu ny xy ra. Xem <a href="#onLoadFinished">
onLoadFinished</a>  tho lun thm v lnh gi li ny</p>

<p>Lu  rng phng php {@link android.app.LoaderManager#initLoader initLoader()}
s tr v {@link android.content.Loader}  c to lp, nhng bn khng
cn bt li mt tham chiu ti n. {@link android.app.LoaderManager} t ng qun l
vng i ca trnh ti. {@link android.app.LoaderManager}
khi ng v dng ti khi cn v duy tr trng thi ca trnh ti
v ni dung i km ca n. Nh hm , bn him khi tng tc trc tip vi cc trnh ti
(thng qua mt v d v vic s dng cc phng php trnh ti  tinh chnh hnh vi
ca mt trnh ti, hy xem v d <a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/LoaderThrottle.html"> LoaderThrottle</a>).
Bn thng s dng nht l cc phng php {@link
android.app.LoaderManager.LoaderCallbacks}  can thip vo tin trnh ti
khi din ra mt s kin c bit.  tho lun thm v ch  ny, hy xem phn <a href="#callback">S dng Phng php Gi li LoaderManager</a>.</p>

<h3 id="restarting">Khi ng li mt Trnh ti</h3>

<p>Khi bn s dng {@link android.app.LoaderManager#initLoader initLoader()}, nh
trnh by bn trn, n s dng mt trnh ti hin hu vi ID c quy nh nu c.
Nu khng c, n s to mt trnh ti. Nhng i khi bn mun b d liu c ca mnh
v bt u li.</p>

<p> b d liu c ca mnh, hy s dng {@link
android.app.LoaderManager#restartLoader restartLoader()}. V d, vic
trin khai {@link android.widget.SearchView.OnQueryTextListener} ny s khi ng li
trnh ti khi truy vn ca ngi dng thay i. Trnh ti cn c khi ng li sao cho
n c th s dng b lc tm kim c iu chnh  thc hin mt truy vn mi:</p>

<pre>
public boolean onQueryTextChanged(String newText) {
    // Called when the action bar search text has changed.  Update
    // the search filter, and restart the loader to do a new query
    // with this filter.
    mCurFilter = !TextUtils.isEmpty(newText) ? newText : null;
    getLoaderManager().restartLoader(0, null, this);
    return true;
}</pre>

<h3 id="callback">S dng cc Phng php Gi li LoaderManager</h3>

<p>{@link android.app.LoaderManager.LoaderCallbacks} l mt giao din gi li
cho php mt my khch tng tc vi {@link android.app.LoaderManager}. </p>
<p>Cc trnh ti, c bit l {@link android.content.CursorLoader}, c k vng s
gi li d liu ca chng sau khi b dng. iu ny cho php ng dng gi li
d liu ca chng qua hot ng hoc cc phng php {@link android.app.Activity#onStop
onStop()} v {@link android.app.Activity#onStart onStart()} ca phn on, sao cho khi
ngi dng quay li mt ng dng, h khng phi ch d liu
ti li. Bn s dng cc phng php {@link android.app.LoaderManager.LoaderCallbacks}
khi cn bit khi no th nn to mt trnh ti mi, v  thng bo vi ng dng khi no
 th n lc  dng s dng d liu ca mt trnh ti.</p>

<p>{@link android.app.LoaderManager.LoaderCallbacks} bao gm nhng phng php
sau:</p>
<ul>
  <li>{@link android.app.LoaderManager.LoaderCallbacks#onCreateLoader onCreateLoader()}
Khi to v tr v mt {@link android.content.Loader} mi cho ID  cho.
</li></ul>
<ul>
  <li> {@link android.app.LoaderManager.LoaderCallbacks#onLoadFinished onLoadFinished()}
 c gi khi mt trnh ti c to trc   hon tt vic ti.
</li></ul>
<ul>
  <li>{@link android.app.LoaderManager.LoaderCallbacks#onLoaderReset onLoaderReset()}
     c gi khi mt trnh ti c to trc  ang c t li, v th m khin d liu
ca n khng sn c.
</li>
</ul>
<p>Nhng phng php ny c m t chi tit hn trong cc phn sau.</p>

<h4 id ="onCreateLoader">onCreateLoader</h4>

<p>Khi bn nh truy cp mt trnh ti (v d, thng qua {@link
android.app.LoaderManager#initLoader initLoader()}), n kim tra xem
trnh ti c quy nh bi ID c tn ti khng. Nu khng, n s kch khi phng php {@link
android.app.LoaderManager.LoaderCallbacks} {@link
android.app.LoaderManager.LoaderCallbacks#onCreateLoader onCreateLoader()}. y
l lc bn to mt trnh ti mi. Thng thng s c mt {@link
android.content.CursorLoader}, nhng bn c th trin khai lp con {@link
android.content.Loader} ca chnh mnh. </p>

<p>Trong v d ny, phng php gi li {@link
android.app.LoaderManager.LoaderCallbacks#onCreateLoader onCreateLoader()}
s to mt {@link android.content.CursorLoader}. Bn phi xy dng
{@link android.content.CursorLoader} bng cch s dng phng php hm dng ca n m yu cu
trn b thng tin cn thit  thc hin mt truy vn ti {@link
android.content.ContentProvider}. C th, n cn:</p>
<ul>
  <li><em>uri</em>  URI ca ni dung cn truy xut. </li>
  <li><em>d tho</em>  Mt danh sch cc ct s tr v. Vic chuyn
<code>null</code> s tr v tt c ct, iu ny khng hiu qu. </li>
  <li><em>la chn</em>  Mt b lc khai bo cc hng no s tr v,
c nh dng nh mt mnh  SQL WHERE (khng gm chnh mnh  WHERE). Vic chuyn
<code>null</code> s tr v tt c hng cho URI  cho. </li>
  <li><em>selectionArgs</em>  Bn c th thm ?s vo la chn,
chng s c thay th bng cc gi tr t <em>selectionArgs</em>, theo th t xut hin trong
la chn. Gi tr s c gn kt thnh cc Xu. </li>
  <li><em>sortOrder</em>  Cch sp xp th t cc hng, c nh dng nh mt mnh  SQL
ORDER BY (khng bao gm chnh mnh  ORDER BY). Vic chuyn <code>null</code> s
s dng th t sp xp mc nh, iu ny c th dn n kt qu khng theo th t.</li>
</ul>
<p>V d:</p>
<pre>
 // If non-null, this is the current filter the user has provided.
String mCurFilter;
...
public Loader&lt;Cursor&gt; onCreateLoader(int id, Bundle args) {
    // This is called when a new Loader needs to be created. This
    // sample only has one Loader, so we don't care about the ID.
    // First, pick the base URI to use depending on whether we are
    // currently filtering.
    Uri baseUri;
  if (mCurFilter != null) {
    baseUri = Uri.withAppendedPath(Contacts.CONTENT_FILTER_URI,
          Uri.encode(mCurFilter));
  } else {
    baseUri = Contacts.CONTENT_URI;
  }

  // Now create and return a CursorLoader that will take care of
  // creating a Cursor for the data being displayed.
  String select = &quot;((&quot; + Contacts.DISPLAY_NAME + &quot; NOTNULL) AND (&quot;
      + Contacts.HAS_PHONE_NUMBER + &quot;=1) AND (&quot;
      + Contacts.DISPLAY_NAME + &quot; != '' ))&quot;;
  return new CursorLoader(getActivity(), baseUri,
      CONTACTS_SUMMARY_PROJECTION, select, null,
      Contacts.DISPLAY_NAME + &quot; COLLATE LOCALIZED ASC&quot;);
}</pre>
<h4 id="onLoadFinished">onLoadFinished</h4>

<p>Phng php ny c gi khi mt trnh ti c to trc   hon thnh vic ti ca mnh.
Phng php ny c bo m s c gi trc khi gii phng d liu cui cng
c cung cp cho trnh ti ny.  Ti im ny, bn nn loi b mi trng hp s dng
d liu c (do n s c gii phng sm), nhng khng nn
t mnh gii phng d liu do trnh ti s hu d liu v s m nhn vic ny.</p>


<p>Trnh ti s gii phng d liu sau khi n bit ng dng ang khng cn
s dng n na.  V d, nu d liu l mt con chy t mt {@link
android.content.CursorLoader}, bn khng nn t mnh gi {@link
android.database.Cursor#close close()} trn d liu . Nu con chy ang c t
trong mt {@link android.widget.CursorAdapter}, bn nn s dng phng php {@link
android.widget.SimpleCursorAdapter#swapCursor swapCursor()} sao cho
 {@link android.database.Cursor} c khng b ng. V d:</p>

<pre>
// This is the Adapter being used to display the list's data.<br
/>SimpleCursorAdapter mAdapter;
...

public void onLoadFinished(Loader&lt;Cursor&gt; loader, Cursor data) {
    // Swap the new cursor in. (The framework will take care of closing the
    // old cursor once we return.)
    mAdapter.swapCursor(data);
}</pre>

<h4 id="onLoaderReset">onLoaderReset</h4>

<p>Phng php ny c gi khi mt trnh ti c to trc  ang c t li, v th m khin
d liu ca n khng sn c. Lnh gi li ny cho php bn tm hiu xem khi no th d liu
s c gii phng  bn c th loi b tham chiu ca mnh ti n. </p>
<p>S trin khai ny gi ra
{@link android.widget.SimpleCursorAdapter#swapCursor swapCursor()}
vi mt gi tr <code>null</code>:</p>

<pre>
// This is the Adapter being used to display the list's data.
SimpleCursorAdapter mAdapter;
...

public void onLoaderReset(Loader&lt;Cursor&gt; loader) {
    // This is called when the last Cursor provided to onLoadFinished()
    // above is about to be closed. We need to make sure we are no
    // longer using it.
    mAdapter.swapCursor(null);
}</pre>


<h2 id="example">V d</h2>

<p>Ly mt v d, sau y l trin khai y  ca {@link
android.app.Fragment} c chc nng hin th mt {@link android.widget.ListView} cha
kt qu ca mt truy vn i vi trnh cung cp ni dung danh b. N s dng mt {@link
android.content.CursorLoader}  qun l truy vn trn trnh cung cp.</p>

<p> mt ng dng truy cp danh b ca mt ngi dng, nh minh ha trong v d ny, bn k khai
ca n phi bao gm quyn
{@link android.Manifest.permission#READ_CONTACTS READ_CONTACTS}.</p>

<pre>
public static class CursorLoaderListFragment extends ListFragment
    implements OnQueryTextListener, LoaderManager.LoaderCallbacks&lt;Cursor&gt; {

    // This is the Adapter being used to display the list's data.
  SimpleCursorAdapter mAdapter;

  // If non-null, this is the current filter the user has provided.
  String mCurFilter;

  @Override public void onActivityCreated(Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    // Give some text to display if there is no data. In a real
    // application this would come from a resource.
    setEmptyText(&quot;No phone numbers&quot;);

    // We have a menu item to show in action bar.
    setHasOptionsMenu(true);

    // Create an empty adapter we will use to display the loaded data.
    mAdapter = new SimpleCursorAdapter(getActivity(),
        android.R.layout.simple_list_item_2, null,
        new String[] { Contacts.DISPLAY_NAME, Contacts.CONTACT_STATUS },
        new int[] { android.R.id.text1, android.R.id.text2 }, 0);
    setListAdapter(mAdapter);

    // Prepare the loader. Either re-connect with an existing one,
    // or start a new one.
    getLoaderManager().initLoader(0, null, this);
  }

  @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    // Place an action bar item for searching.
    MenuItem item = menu.add(&quot;Search&quot;);
    item.setIcon(android.R.drawable.ic_menu_search);
    item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
    SearchView sv = new SearchView(getActivity());
    sv.setOnQueryTextListener(this);
    item.setActionView(sv);
  }

  public boolean onQueryTextChange(String newText) {
    // Called when the action bar search text has changed. Update
    // the search filter, and restart the loader to do a new query
    // with this filter.
    mCurFilter = !TextUtils.isEmpty(newText) ? newText : null;
    getLoaderManager().restartLoader(0, null, this);
    return true;
  }

  @Override public boolean onQueryTextSubmit(String query) {
    // Don't care about this.
    return true;
  }

  @Override public void onListItemClick(ListView l, View v, int position, long id) {
    // Insert desired behavior here.
    Log.i(&quot;FragmentComplexList&quot;, &quot;Item clicked: &quot; + id);
  }

  // These are the Contacts rows that we will retrieve.
  static final String[] CONTACTS_SUMMARY_PROJECTION = new String[] {
    Contacts._ID,
    Contacts.DISPLAY_NAME,
    Contacts.CONTACT_STATUS,
    Contacts.CONTACT_PRESENCE,
    Contacts.PHOTO_ID,
    Contacts.LOOKUP_KEY,
  };
  public Loader&lt;Cursor&gt; onCreateLoader(int id, Bundle args) {
    // This is called when a new Loader needs to be created. This
    // sample only has one Loader, so we don't care about the ID.
    // First, pick the base URI to use depending on whether we are
    // currently filtering.
    Uri baseUri;
    if (mCurFilter != null) {
      baseUri = Uri.withAppendedPath(Contacts.CONTENT_FILTER_URI,
          Uri.encode(mCurFilter));
    } else {
      baseUri = Contacts.CONTENT_URI;
    }

    // Now create and return a CursorLoader that will take care of
    // creating a Cursor for the data being displayed.
    String select = &quot;((&quot; + Contacts.DISPLAY_NAME + &quot; NOTNULL) AND (&quot;
        + Contacts.HAS_PHONE_NUMBER + &quot;=1) AND (&quot;
        + Contacts.DISPLAY_NAME + &quot; != '' ))&quot;;
    return new CursorLoader(getActivity(), baseUri,
        CONTACTS_SUMMARY_PROJECTION, select, null,
        Contacts.DISPLAY_NAME + &quot; COLLATE LOCALIZED ASC&quot;);
  }

  public void onLoadFinished(Loader&lt;Cursor&gt; loader, Cursor data) {
    // Swap the new cursor in. (The framework will take care of closing the
    // old cursor once we return.)
    mAdapter.swapCursor(data);
  }

  public void onLoaderReset(Loader&lt;Cursor&gt; loader) {
    // This is called when the last Cursor provided to onLoadFinished()
    // above is about to be closed. We need to make sure we are no
    // longer using it.
    mAdapter.swapCursor(null);
  }
}</pre>
<h3 id="more_examples">Thm V d</h3>

<p>C mt vi mu khc trong <strong>ApiDemos</strong>
minh ha cch s dng cc trnh ti:</p>
<ul>
  <li><a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/LoaderCursor.html">
LoaderCursor</a>  Mt phin bn hon chnh ca
on m HTML trnh by  trn.</li>
  <li><a href="{@docRoot}resources/samples/ApiDemos/src/com/example/android/apis/app/LoaderThrottle.html"> LoaderThrottle</a>  Mt v d v cch s dng iu chnh  gim
s truy vn m mt trnh cung cp ni dung thc hin khi d liu ca n thay i.</li>
</ul>

<p> bit thng tin v vic ti xung v ci t cc mu SDK, hy xem phn <a href="http://developer.android.com/resources/samples/get.html"> Ti
Mu</a>. </p>