topics/ui/menus.jd

page.title=Menu
parent.title=Giao din Ngi dng
parent.link=index.html
@jd:body

<div id="qv-wrapper">
<div id="qv">
  <h2>Trong ti liu ny</h2>
<ol>
  <li><a href="#xml">nh ngha mt Menu trong XML</a></li>
  <li><a href="#options-menu">To mt Menu Ty chn</a>
    <ol>
      <li><a href="#RespondingOptionsMenu">X l s kin nhp</a></li>
      <li><a href="#ChangingTheMenu">Thay i cc mc menu vo thi gian chy</a></li>
    </ol>
  </li>
  <li><a href="#context-menu">To mt Menu Ng cnh</a>
    <ol>
      <li><a href="#FloatingContextMenu">To mt menu ng cnh ni</a></li>
      <li><a href="#CAB">S dng ch  hnh ng theo ng cnh</a></li>
    </ol>
  </li>
  <li><a href="#PopupMenu">To mt Menu Bt ln</a>
    <ol>
      <li><a href="#PopupEvents">X l s kin nhp</a></li>
    </ol>
  </li>
  <li><a href="#groups">To Nhm Menu</a>
    <ol>
      <li><a href="#checkable">S dng mc menu c th chn</a></li>
    </ol>
  </li>
  <li><a href="#intents">Thm Mc Menu da trn  nh</a>
    <ol>
      <li><a href="#AllowingToAdd">Cho php hot ng ca bn c thm vo cc menu khc</a></li>
    </ol>
  </li>
</ol>

  <h2>Lp kha</h2>
  <ol>
    <li>{@link android.view.Menu}</li>
    <li>{@link android.view.MenuItem}</li>
    <li>{@link android.view.ContextMenu}</li>
    <li>{@link android.view.ActionMode}</li>
  </ol>

  <h2>Xem thm</h2>
  <ol>
    <li><a href="{@docRoot}guide/topics/ui/actionbar.html">Thanh Hnh ng</a></li>
    <li><a href="{@docRoot}guide/topics/resources/menu-resource.html">Ti nguyn Menu</a></li>
    <li><a href="http://android-developers.blogspot.com/2012/01/say-goodbye-to-menu-button.html">Ni
Tm bit vi Nt Menu</a></li>
  </ol>
</div>
</div>

<p>Menu l mt thnh phn giao din ngi dng ph bin trong nhiu loi ng dng.  cung cp mt
tri nghim ngi dng quen thuc v nht qun, bn nn s dng cc API {@link android.view.Menu}  trnh by
hnh ng ngi dng v cc ty chn khc trong hot ng ca mnh.</p>

<p>Bt u vi Android 3.0 (API mc 11), cc thit b da trn nn tng Android khng cn phi
cung cp mt nt <em>Menu</em> chuyn dng na. Vi s thay i ny, cc ng dng Android cn trnh khi
s ph thuc vo bng iu khin menu 6 mc truyn thng ny m thay vo  cung cp mt thanh hnh ng  trnh by
cc hnh ng ngi dng thng dng.</p>

<p>Mc d thit k v tri nghim ngi dng i vi mt s mc menu  thay i, ng ngha  nh ngha
tp hp hnh ng v ty chn th vn da trn cc API {@link android.view.Menu}. Hng dn
ny trnh by cch to ba loi menu hay trnh by hnh ng c bn trn tt c
phin bn Android:</p>

<dl>
  <dt><strong>Menu ty chn v thanh hnh ng</strong></dt>
    <dd><a href="#options-menu">Menu ty chn</a> l tp hp cc mc menu c bn cho mt
hot ng.  l ni bn nn t cc hnh ng c tc ng chung ti ng dng, chng hn nh
"Tm kim," "Son e-mail" v "Ci t."
  <p>Nu bn ang pht trin cho phin bn Android 2.3 hoc thp hn, ngi dng c th
hin bng iu khin menu ty chn bng cch nhn nt <em>Menu</em>.</p>
  <p>Trn phin bn Android 3.0 tr ln, cc mc t menu ty chn c trnh by bi <a href="{@docRoot}guide/topics/ui/actionbar.html">thanh hnh ng</a>, l s kt hp gia cc mc hnh ng
trn mn hnh v cc ty chn trn. Bt u vi phin bn Android 3.0, nt <em>Menu</em> b b i (mt s
thit b
khng c), v th bn nn chuyn sang s dng thanh hnh ng  cho php truy cp vo hnh ng v
cc ty chn khc.</p>
  <p>Xem phn v <a href="#options-menu">To mt Menu Ty chn</a>.</p>
    </dd>

  <dt><strong>Menu ng cnh v ch  hnh ng theo ng cnh</strong></dt>

   <dd>Menu ng cnh l mt <a href="#FloatingContextMenu">menu ni</a> xut hin khi
ngi dng thc hin nhp gi trn mt phn t. N cung cp cc hnh ng nh hng ti ni dung hoc
khung ng cnh c chn.
  <p>Khi pht trin cho phin bn Android 3.0 tr ln, thay vo , bn nn s dng <a href="#CAB">ch  hnh ng theo ng cnh</a>  kch hot cc hnh ng trn ni dung c chn. Ch  ny hin th
cc mc hnh ng nh hng ti ni dung c chn trong mt thanh  trn cng ca mn hnh v cho php ngi dng
chn nhiu mc.</p>
  <p>Xem phn ni v <a href="#context-menu">To Menu Ng cnh</a>.</p>
</dd>

  <dt><strong>Menu bt ln</strong></dt>
    <dd>Menu bt ln s hin th danh sch cc mc trong mt danh sch thng ng c neo vo dng xem
 gi ra menu. Nn cung cp mt phn trn gm cc hnh ng lin quan ti ni dung c th hoc
nhm cung cp cc ty chn cho phn th hai ca mt lnh. Cc hnh ng trong mt menu bt ln
<strong>khng</strong> nn trc tip nh hng ti ni dung tng ng&mdash; l vic ca hnh ng ng cnh
. Thay vo , menu bt ln p dng cho cc hnh ng m rng lin quan ti cc vng ni dung trong hot ng
ca bn.
  <p>Xem phn v <a href="#PopupMenu">To mt Menu Bt ln</a>.</p>
</dd>
</dl>


<h2 id="xml">nh ngha mt Menu trong XML</h2>

<p>i vi tt c cc loi menu, Android cung cp mt nh dng XML chun  nh ngha cc mc menu.
Thay v xy dng mt menu trong m ca hot ng ca bn, bn nn nh ngha mt menu v tt c cc mc ca n trong mt
<a href="{@docRoot}guide/topics/resources/menu-resource.html">ti nguyn menu</a> XML. Khi , bn c th
bung ti nguyn menu (ti n nh mt i tng {@link android.view.Menu}) trong hot ng hoc
phn on ca mnh.</p>

<p>S dng mt ti nguyn menu l mt cch lm hay v mt vi l do:</p>
<ul>
  <li>N d trc quan ha cu trc menu trong XML hn.</li>
  <li>N tch ring ni dung cho menu vi m hnh vi ca ng dng ca bn.</li>
  <li>N cho php bn to cc cu hnh menu phi sinh cho cc phin bn nn tng,
kch c mn hnh khc nhau v cc cu hnh khc bng cch tn dng khun kh <a href="{@docRoot}guide/topics/resources/index.html">ti nguyn ng dng</a>.</li>
</ul>

<p> nh ngha menu, hy to mt tp XML bn trong th mc <code>res/menu/</code>
d n ca bn v xy dng menu vi cc phn t sau:</p>
<dl>
  <dt><code>&lt;menu></code></dt>
    <dd>nh ngha mt {@link android.view.Menu},  l mt b cha cc mc menu. Phn t
<code>&lt;menu></code> phi l mt nt gc cho tp v c th gi mt hoc nhiu phn t
<code>&lt;item></code> v <code>&lt;group></code>.</dd>

  <dt><code>&lt;item></code></dt>
    <dd>To mt {@link android.view.MenuItem}, n biu din mt mc n trong mt menu. Phn t
ny c th cha mt phn t <code>&lt;menu></code> c lng nhau  to mt menu con.</dd>

  <dt><code>&lt;group></code></dt>
    <dd>Mt b cha ty chn, v hnh cho cc phn t {@code &lt;item&gt;}. N cho php bn
phn loi cc mc menu sao cho chng chia s cc tnh cht nh trng thi hin hot v kh nng hin th.  bit thm
thng tin, hy xem phn ni v <a href="#groups">To Nhm Menu</a>.</dd>
</dl>


<p>Sau y l mt menu v d c tn l <code>game_menu.xml</code>:</p>
<pre>
&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;menu xmlns:android="http://schemas.android.com/apk/res/android"&gt;
    &lt;item android:id="@+id/new_game"
          android:icon="@drawable/ic_new_game"
          android:title="@string/new_game"
          android:showAsAction="ifRoom"/&gt;
    &lt;item android:id="@+id/help"
          android:icon="@drawable/ic_help"
          android:title="@string/help" /&gt;
&lt;/menu&gt;
</pre>

<p>Phn t <code>&lt;item></code> h tr mt vi thuc tnh bn c th s dng  nh ngha biu hin bn ngoi
v hnh vi ca mt mc. Cc mc trong menu trn bao gm nhng thuc tnh sau:</p>

<dl>
  <dt>{@code android:id}</dt>
    <dd>Mt ID ti nguyn duy nht i vi mc, n cho php ng dng c th nhn ra mc
khi ngi dng chn n.</dd>
  <dt>{@code android:icon}</dt>
    <dd>Mt tham chiu ti mt ni dung v c  dng lm biu tng ca mc.</dd>
  <dt>{@code android:title}</dt>
    <dd>Mt tham chiu ti mt xu  dng lm tiu  ca mc.</dd>
  <dt>{@code android:showAsAction}</dt>
    <dd>Quy nh thi im v cch thc mc ny nn xut hin nh mt mc hnh ng trong <a href="{@docRoot}guide/topics/ui/actionbar.html">thanh hnh ng</a>.</dd>
</dl>

<p>y l nhng thuc tnh quan trng nht bn nn s dng, nhng cn nhiu thuc tnh sn c khc.
 bit thng tin v tt c thuc tnh c h tr, hy xem ti liu <a href="{@docRoot}guide/topics/resources/menu-resource.html">Ti nguyn Menu</a>.</p>

<p>Bn c th thm mt menu con vo mt mc trong bt k menu no (ngoi tr menu con) bng cch thm mt phn t {@code &lt;menu&gt;}
lm con ca {@code &lt;item&gt;}. Cc menu con thng hu ch khi ng dng ca bn c nhiu
chc nng m c th c t chc thnh cc ch , nh cc mc trong thanh menu ca mt ng dng PC (Tp,
Chnh sa, Dng xem, v.v.). V d:</p>

<pre>
&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;menu xmlns:android="http://schemas.android.com/apk/res/android"&gt;
    &lt;item android:id="@+id/file"
          android:title="@string/file" &gt;
        &lt;!-- "file" submenu --&gt;
        &lt;menu&gt;
            &lt;item android:id="@+id/create_new"
                  android:title="@string/create_new" /&gt;
            &lt;item android:id="@+id/open"
                  android:title="@string/open" /&gt;
        &lt;/menu&gt;
    &lt;/item&gt;
&lt;/menu&gt;
</pre>

<p> s dng menu trong hot ng ca mnh, bn cn bung ti nguyn menu (chuyn ti nguyn XML
thnh mt i tng c th lp trnh) bng cch s dng {@link android.view.MenuInflater#inflate(int,Menu)
MenuInflater.inflate()}. Trong nhng phn sau, bn s bit cch bung mt menu i vi mi
loi menu.</p>


<h2 id="options-menu">To mt Menu Ty chn</h2>

<div class="figure" style="width:200px;margin:0">
  <img src="{@docRoot}images/options_menu.png" height="333" alt="" />
  <p class="img-caption"><strong>Hnh 1.</strong> Cc menu ty chn trong
Trnh duyt, trn Android 2.3.</p>
</div>

<p>Menu ty chn l ni bn nn a vo hnh ng v cc ty chn khc lin quan ti
ng cnh hot ng hin ti, chng hn nh "Tm kim," "Son e-mail," v "Ci t."</p>

<p>Ni m cc mc trong menu ty chn ca bn xut hin trn mn hnh s ph thuc vo phin bn m bn
pht trin ng dng ca mnh cho:</p>

<ul>
  <li>Nu bn pht trin ng dng ca mnh cho phin bn <strong>Android 2.3.x (API mc 10) hoc
thp hn</strong>, ni dung ca menu ty chn s xut hin  di cng mn hnh khi ngi dng
nhn nt <em>Menu</em> nh minh ha trong hnh 1. Khi c m, phn hin th u tin l
menu biu tng
vi ti a su mc menu. Nu menu ca bn bao gm nhiu hn su mc, Android s t
mc th su v phn cn li vo mt menu trn m ngi dng c th m bng cch chn
<em>Thm na</em>.</li>

  <li>Nu bn pht trin ng dng ca mnh cho phin bn <strong>Android 3.0 (API mc 11) v
cao hn</strong>, cc mc t menu ty chn sn  trong <a href="{@docRoot}guide/topics/ui/actionbar.html">thanh hnh ng</a>. Theo mc nh, h thng
t tt c cc mc trong phn trn hnh ng m ngi dng c th hin bng biu tng trn hnh ng pha
bn phi ca thanh hnh ng (hoc bng cch nhn nt <em>Menu</em> ca thit b nu c).
kch hot
truy cp nhanh vo cc hnh ng quan trng, bn c th a ln mt vi mc xut hin trong thanh hnh ng bng cch thm
{@code android:showAsAction="ifRoom"} vo phn t {@code &lt;item&gt;} tng ng (xem hnh
2). <p> bit thm thng tin v cc mc hnh ng v hnh vi khc ca thanh hnh ng, hy xem hng dn <a href="{@docRoot}guide/topics/ui/actionbar.html">Thanh Hnh ng</a>. </p>
<p class="note"><strong>Lu :</strong> Ngay c khi bn <em>khng</em> ang pht trin cho phin bn Android 3.0 hoc
cao hn, bn c th xy dng b tr thanh hnh ng ca chnh mnh cho hiu ng tng t.  xem v d v cch bn c th h tr cc phin bn cao hn
ca Android bng mt thanh hnh ng, hy xem mu <a href="{@docRoot}resources/samples/ActionBarCompat/index.html">Tng thch vi Thanh Hnh ng</a>
.</p>
</li>
</ul>

<img src="{@docRoot}images/ui/actionbar.png" alt="" />
<p class="img-caption"><strong>Hnh 2.</strong> Thanh hnh ng t ng dng <a href="{@docRoot}resources/samples/HoneycombGallery/index.html">Honeycomb Gallery</a>, hin th
cc tab iu hng v mt mc hnh ng my nh (cng vi nt trn hnh ng).</p>

<p>Bn c th khai bo cc mc cho menu ty chn t lp con {@link android.app.Activity}
ca bn hoc mt lp con {@link android.app.Fragment}. Nu c hot ng ca bn v (cc) phn on
u khai bo cc mc cho menu ty chn, chng s c kt hp li trong UI. Cc mc ca hot ng xut hin
trc, sau  l cc mc ca tng phn on theo th t phn on c thm vo
hot ng. Nu cn, bn c th sp xp li cc mc menu bng thuc tnh {@code android:orderInCategory}
trong mi {@code &lt;item&gt;} m bn cn di chuyn.</p>

<p> quy nh menu ty chn cho mt hot ng, hy khng ch {@link
android.app.Activity#onCreateOptionsMenu(Menu) onCreateOptionsMenu()} (cc phn on cung cp
phng php gi li {@link android.app.Fragment#onCreateOptionsMenu onCreateOptionsMenu()} ca chnh mnh). Trong
phng php ny, bn c th bung ti nguyn menu ca mnh (<a href="#xml">c nh ngha trong XML</a>) vo {@link
android.view.Menu} c cung cp trong phng php gi li. V d:</p>

<pre>
&#64;Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = {@link android.app.Activity#getMenuInflater()};
    inflater.inflate(R.menu.game_menu, menu);
    return true;
}
</pre>

<p>Bn cng c th thm cc mc menu bng cch s dng {@link android.view.Menu#add(int,int,int,int)
add()} v truy xut cc mc bng {@link android.view.Menu#findItem findItem()}  xem li
tnh cht ca chng bng cc API {@link android.view.MenuItem}.</p>

<p>Nu bn pht trin ng dng ca mnh cho phin bn Android 2.3.x v thp hn, h thng gi {@link
android.app.Activity#onCreateOptionsMenu(Menu) onCreateOptionsMenu()}  to menu ty chn
khi ngi dng m menu ln u tin. Nu bn pht trin cho phin bn Android 3.0 vo cao hn,
h thng s gi {@link android.app.Activity#onCreateOptionsMenu(Menu) onCreateOptionsMenu()} khi
bt u hot ng  hin th cc mc cho thanh hnh ng.</p>


<h3 id="RespondingOptionsMenu">X l s kin nhp</h3>

<p>Khi ngi dng chn mt mc t menu ty chn (bao gm cc mc hnh ng trong thanh hnh ng),
h thng s gi phng php {@link android.app.Activity#onOptionsItemSelected(MenuItem)
onOptionsItemSelected()} ca hot ng ca bn. Phng php ny thng qua {@link android.view.MenuItem} c chn. Bn
c th nhn bit mc bng cch gi {@link android.view.MenuItem#getItemId()}, n tr v ID duy nht
cho mc menu (c nh ngha bi thuc tnh {@code android:id} trong ti nguyn menu hoc bng mt
s nguyn c cp cho phng php {@link android.view.Menu#add(int,int,int,int) add()}). Bn c th khp
ID ny vi cc mc menu  bit  thc hin hnh ng ph hp. V d:</p>

<pre>
&#64;Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle item selection
    switch (item.getItemId()) {
        case R.id.new_game:
            newGame();
            return true;
        case R.id.help:
            showHelp();
            return true;
        default:
            return super.onOptionsItemSelected(item);
    }
}
</pre>

<p>Khi bn x l thnh cng mt mc menu, tr v {@code true}. Nu khng x l c
mc menu, bn nn gi trin khai siu lp ca {@link
android.app.Activity#onOptionsItemSelected(MenuItem) onOptionsItemSelected()} (trin khai
mc nh tr v sai).</p>

<p>Nu hot ng ca bn bao gm cc phn on, trc tin h thng s gi {@link
android.app.Activity#onOptionsItemSelected(MenuItem) onOptionsItemSelected()} cho hot ng, ri mi
cho tng phn on (theo th t thm phn on) ti khi tr v
{@code true} hoc tt c phn on u c gi.</p>

<p class="note"><strong>Mo:</strong> Android 3.0 thm kh nng cho php bn nh ngha hnh vi
khi nhp i vi mt mc menu trong XML, bng cch s dng thuc tnh {@code android:onClick}. Gi tr cho
thuc tnh phi l tn ca mt phng php c nh ngha bi hot ng s dng menu. Phng php
phi cng khai v chp nhn mt tham s {@link android.view.MenuItem} n&mdash;khi h thng
gi phng php ny, n thng qua mc menu c chn.  bit thm thng tin v v d, hy xem ti liu <a href="{@docRoot}guide/topics/resources/menu-resource.html">Ti nguyn Menu</a>.</p>

<p class="note"><strong>Mo:</strong> Nu ng dng ca bn cha nhiu hot ng v
mt s chng cung cp menu ty chn tng t, hy xem xt to
 mt hot ng ch trin khai cc phng php {@link android.app.Activity#onCreateOptionsMenu(Menu)
onCreateOptionsMenu()} v {@link android.app.Activity#onOptionsItemSelected(MenuItem)
onOptionsItemSelected()}. Sau , m rng lp ny i vi mi hot ng cn chia s
menu ty chn tng t. Bng cch ny, bn c th qun l mt b m  x l cc hnh ng
menu v tng lp hu du k tha cc hnh vi menu.
Nu bn mun thm cc mc menu vo mt trong cc hot ng hu du,
hy khng ch {@link android.app.Activity#onCreateOptionsMenu(Menu)
onCreateOptionsMenu()} trong hot ng . Gi {@code super.onCreateOptionsMenu(menu)} sao cho
cc mc menu gc c to, sau  thm cc mc menu mi bng {@link
android.view.Menu#add(int,int,int,int) menu.add()}. Bn cng c th khng ch hnh vi
ca siu lp i vi cc mc menu ring l.</p>


<h3 id="ChangingTheMenu">Thay i cc mc menu vo thi gian chy</h3>

<p>Sau khi h thng gi {@link android.app.Activity#onCreateOptionsMenu(Menu)
onCreateOptionsMenu()}, n s gi li mt thc th ca {@link android.view.Menu} m bn a vo v
s khng gi li {@link android.app.Activity#onCreateOptionsMenu(Menu) onCreateOptionsMenu()}
tr khi menu b v hiu ha v l do no . Tuy nhin, bn ch nn s dng {@link
android.app.Activity#onCreateOptionsMenu(Menu) onCreateOptionsMenu()}  to trng thi menu
ban u ch khng phi  thc hin thay i trong vng i ca hot ng.</p>

<p>Nu bn mun sa i menu ty chn da trn
cc s kin xy ra trong vng i ca hot ng, bn c th lm vy trong phng php
 {@link android.app.Activity#onPrepareOptionsMenu(Menu) onPrepareOptionsMenu()}. Phng php
ny chuyn cho bn i tng {@link android.view.Menu} nh hin ang c  bn c th sa i n,
chng hn nh thm, xa b, hoc v hiu ha cc mc. (Phn on cng cung cp lnh gi li {@link
android.app.Fragment#onPrepareOptionsMenu onPrepareOptionsMenu()}.)</p>

<p>Trn phin bn Android 2.3.x v thp hn, h thng gi {@link
android.app.Activity#onPrepareOptionsMenu(Menu)
onPrepareOptionsMenu()} mi ln ngi dng m menu ty chn (nhn nt <em>Menu</em>
).</p>

<p>Trn phin bn Android 3.0 tr ln, menu ty chn c coi nh lun m khi cc mc menu c
trnh by trong thanh hnh ng. Khi mt s kin xy ra v bn mun thc hin mt cp nht menu, bn phi
gi {@link android.app.Activity#invalidateOptionsMenu invalidateOptionsMenu()}  yu cu
h thng gi {@link android.app.Activity#onPrepareOptionsMenu(Menu) onPrepareOptionsMenu()}.</p>

<p class="note"><strong>Lu :</strong>
Bn khng nn thay i cc mc trong menu ty chn da trn {@link android.view.View} ang
trong tiu im. Khi  ch  cm ng (khi ngi dng khng s dng bi xoay hay d-pad), cc dng xem
khng th ly tiu im, v th bn khng nn s dng tiu im lm c s  sa i
cc mc trong menu ty chn. Nu bn mun cung cp cc mc menu nhy cm vi ng cnh cho mt {@link
android.view.View}, hy s dng mt <a href="#context-menu">Menu Ng cnh</a>.</p>


<h2 id="context-menu">To mt Menu Ng cnh</h2>

<div class="figure" style="width:420px;margin-top:-1em">
  <img src="{@docRoot}images/ui/menu-context.png" alt="" />
  <p class="img-caption"><strong>Hnh 3.</strong> nh chp mn hnh mt menu ng cnh ni (tri)
v thanh hnh ng ng cnh (phi).</p>
</div>

<p>Menu ng cnh s a ra cc hnh ng nh hng ti mt mc hoc khung ng cnh c th trong UI. Bn
c th cung cp mt menu ng cnh cho bt k dng xem no, nhng chng thng c s dng nhiu nht cho cc mc trong mt {@link
android.widget.ListView}, {@link android.widget.GridView}, hoc cc b su tp dng xem khc m
ngi dng c th thc hin hnh ng trc tip trn mi mc.</p>

<p>C hai cch  cung cp cc hnh ng ng cnh:</p>
<ul>
  <li>Trong mt <a href="#FloatingContextMenu">menu ng cnh ni</a>. Menu xut hin nh mt
danh sch ni gm nhiu mc menu (tng t nh mt hp thoi) khi ngi dng thc hin nhp gi (nhn v
gi) trn mt dng xem c khai bo h tr menu ng cnh. Ngi dng c th thc hin hnh ng
ng cnh trn mt mc vo mt thi im.</li>

  <li>Trong <a href="#CAB">ch  hnh ng theo ng cnh</a>. Ch  ny l mt h thng trin khai
{@link android.view.ActionMode} c chc nng hin th mt <em>thanh hnh ng ng cnh</em>  bn trn
mn hnh vi cc mc hnh ng nh hng ti (cc) mc c chn. Khi ch  ny hin hot, ngi dng
c th thc hin mt hnh ng trn nhiu mc ngay lp tc (nu ng dng ca bn cho php).</li>
</ul>

<p class="note"><strong>Lu :</strong> Ch  hnh ng theo ng cnh sn c trn phin bn Android 3.0 (API
mc 11) v cao hn v l k thut c u tin cho vic hin th cc hnh ng theo ng cnh khi
sn c. Nu ng dng ca bn h tr cc phin bn thp hn 3.0, vy bn nn quay li menu ng cnh
ni trn nhng thit b .</p>


<h3 id="FloatingContextMenu">To mt menu ng cnh ni</h3>

<p> cung cp mt menu ng cnh ni:</p>
<ol>
  <li>ng k {@link android.view.View} m menu ng cnh nn c lin kt vi bng cch
gi {@link android.app.Activity#registerForContextMenu(View) registerForContextMenu()} v chuyn
cho n {@link android.view.View}.
  <p>Nu hot ng ca bn s dng mt {@link android.widget.ListView} hoc {@link android.widget.GridView} v
bn mun tng mc cung cp cng menu ng cnh, hy ng k tt c mc cho mt menu ng cnh bng cch
chuyn {@link android.widget.ListView} hoc {@link android.widget.GridView} cho {@link
android.app.Activity#registerForContextMenu(View) registerForContextMenu()}.</p>
</li>

  <li>Trin khai phng php {@link
android.view.View.OnCreateContextMenuListener#onCreateContextMenu onCreateContextMenu()}
trong {@link android.app.Activity} hoc {@link android.app.Fragment} ca bn.
  <p>Khi dng xem c ng k nhn c mt s kin nhp gi, h thng s gi phng php {@link
android.view.View.OnCreateContextMenuListener#onCreateContextMenu onCreateContextMenu()}
ca bn. y l ni bn nh ngha cc mc menu, thng bng cch bung mt ti nguyn menu. V
d:</p>
<pre>
&#64;Override
public void onCreateContextMenu(ContextMenu menu, View v,
                                ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.context_menu, menu);
}
</pre>

<p>{@link android.view.MenuInflater} cho php bn bung menu ng cnh t mt <a href="{@docRoot}guide/topics/resources/menu-resource.html">ti nguyn menu</a>. Cc tham s ca phng php gi li
bao gm {@link android.view.View}
m ngi dng  chn v mt i tng {@link android.view.ContextMenu.ContextMenuInfo} cung cp
thng tin b sung v mc c chn. Nu hot ng ca bn c mt vi dng xem m mi dng cung cp
mt menu ng cnh khc nhau, bn c th s dng nhng tham s ny  xc nh menu ng cnh no cn
bung.</p>
</li>

<li>Trin khai {@link android.app.Activity#onContextItemSelected(MenuItem)
onContextItemSelected()}.
  <p>Khi ngi dng chn mt mc menu, h thng s gi phng php ny  bn c th thc hin
hnh ng ph hp. V d:</p>

<pre>
&#64;Override
public boolean onContextItemSelected(MenuItem item) {
    AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
    switch (item.getItemId()) {
        case R.id.edit:
            editNote(info.id);
            return true;
        case R.id.delete:
            deleteNote(info.id);
            return true;
        default:
            return super.onContextItemSelected(item);
    }
}
</pre>

<p>Phng php {@link android.view.MenuItem#getItemId()} s truy vn ID cho
mc menu c chn, bn nn gn mc ny cho tng mc menu trong XML bng cch s dng thuc tnh {@code
android:id} nh trnh by trong phn v <a href="#xml">nh ngha mt Menu trong
XML</a>.</p>

<p>Khi bn x l thnh cng mt mc menu, tr v {@code true}. Nu bn khng x l mc menu,
bn nn chuyn mc menu  ti trin khai siu lp. Nu hot ng ca bn bao gm nhiu phn on,
hot ng s nhn c lnh gi li ny trc. Bng cch gi siu lp khi cha c x l, h thng
s chuyn s kin ti phng php gi li tng ng trong tng phn on, ln lt (theo th t
thm phn on) ti khi {@code true} hoc {@code false} c tr v. (Trin khai
mc nh cho {@link android.app.Activity} v {@code android.app.Fragment} s tr v {@code
false}, v th bn nn lun gi siu lp khi cha c x l.)</p>
</li>
</ol>


<h3 id="CAB">S dng ch  hnh ng theo ng cnh</h3>

<p>Ch  hnh ng theo ng cnh l mt trin khai h thng {@link android.view.ActionMode}
tp trung vo tng tc ngi dng hng ti vic thc hin cc hnh ng theo ng cnh. Khi mt
ngi dng kch hot ch  ny bng cch chn mt mc, mt <em>thanh hnh ng ng cnh</em> s xut hin bn trn
mn hnh  trnh by cc hnh ng m ngi dng c th thc hin trn (cc) mc ang c chn. Trong khi
ch  ny c kch hot, ngi dng c th chn nhiu mc (nu bn cho php), b chn mc, v tip tc
iu hng trong hot ng (min l bn sn lng cho php). Ch  hnh ng b v hiu ha
v thanh hnh ng ng cnh bin mt khi ngi dng b chn tt c cc mc, nhn nt QUAY LI,
hoc chn hnh ng <em>Xong</em>  pha bn tri ca thanh.</p>

<p class="note"><strong>Lu :</strong> Thanh hnh ng ng cnh khng nht thit
phi c lin kt vi <a href="{@docRoot}guide/topics/ui/actionbar.html">thanh hnh ng</a>. Chng vn hnh
c lp, mc d thanh hnh ng ng cnh  ln v tr ca thanh hnh ng
v mt hin th.</p>

<p>Nu bn ang pht trin cho phin bn Android 3.0 (API mc 11) hoc cao hn, bn
nn s dng ch  hnh ng theo ng cnh  trnh by cc hnh ng ng cnh, thay v s dng <a href="#FloatingContextMenu">menu ng cnh ni</a>.</p>

<p>i vi cc dng xem cung cp hnh ng ng cnh, bn nn thng xuyn gi ra ch  hnh ng theo ng cnh
khi xy ra mt trong hai s kin sau (hoc c hai):</p>
<ul>
  <li>Ngi dng thc hin nhp gi trn dng xem.</li>
  <li>Ngi dng chn mt hp kim hoc mt thnh phn UI tng t trong dng xem.</li>
</ul>

<p>Cch ng dng ca bn gi ra ch  hnh ng theo ng cnh v nh ngha hnh vi cho tng
hnh ng ph thuc vo thit k ca bn. C bn c hai thit k:</p>
<ul>
  <li>i vi cc hnh ng ng cnh trn cc dng xem ring l, ty .</li>
  <li>i vi cc hnh ng ng cnh hng lot trn cc nhm mc trong mt {@link
android.widget.ListView} hoc {@link android.widget.GridView} (cho php ngi dng chn nhiu
mc v thc hin mt hnh ng trn tt c).</li>
</ul>

<p>Cc phn sau m t phn thit lp cn thit i vi tng kch bn.</p>


<h4 id="CABforViews">Kch hot ch  hnh ng theo ng cnh cho cc dng xem ring l</h4>

<p>Nu mun gi ra ch  hnh ng theo ng cnh ch khi ngi dng chn cc dng xem
c th, bn nn:</p>
<ol>
  <li>Trin khai giao din {@link android.view.ActionMode.Callback}. Trong cc phng php gi li ca giao din, bn
c th quy nh cc hnh ng cho thanh hnh ng ng cnh, hi p cc s kin nhp trn mc hnh ng, v
x l cc s kin vng i khc i vi ch  hnh ng.</li>
  <li>Gi {@link android.app.Activity#startActionMode startActionMode()} khi bn mun hin th
thanh (chng hn nh khi ngi dng nhp gi dng xem).</li>
</ol>

<p>V d:</p>

<ol>
  <li>Trin khai giao din {@link android.view.ActionMode.Callback ActionMode.Callback}:
<pre>
private ActionMode.Callback mActionModeCallback = new ActionMode.Callback() {

    // Called when the action mode is created; startActionMode() was called
    &#64;Override
    public boolean onCreateActionMode(ActionMode mode, Menu menu) {
        // Inflate a menu resource providing context menu items
        MenuInflater inflater = mode.getMenuInflater();
        inflater.inflate(R.menu.context_menu, menu);
        return true;
    }

    // Called each time the action mode is shown. Always called after onCreateActionMode, but
    // may be called multiple times if the mode is invalidated.
    &#64;Override
    public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
        return false; // Return false if nothing is done
    }

    // Called when the user selects a contextual menu item
    &#64;Override
    public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
        switch (item.getItemId()) {
            case R.id.menu_share:
                shareCurrentItem();
                mode.finish(); // Action picked, so close the CAB
                return true;
            default:
                return false;
        }
    }

    // Called when the user exits the action mode
    &#64;Override
    public void onDestroyActionMode(ActionMode mode) {
        mActionMode = null;
    }
};
</pre>

<p>Lu  rng nhng phng php gi li s kin ny hu nh ging vi cc phng php gi li i vi <a href="#options-menu">menu ty chn</a>, khc  ch tng phng php cng chuyn i tng {@link
android.view.ActionMode} c lin kt vi s kin . Bn c th s dng cc API {@link
android.view.ActionMode}  thc hin nhng thay i khc nhau vi CAB, chng hn nh sa i tiu  v
ph  bng {@link android.view.ActionMode#setTitle setTitle()} v {@link
android.view.ActionMode#setSubtitle setSubtitle()} (hu ch khi mun cho bit c bao nhiu mc
c chn).</p>

<p>Cng lu  rng cc b mu trn s t bin {@code mActionMode} l rng khi
ch  hnh ng b hy.  bc tip theo, bn s thy cch n c khi to v vic lu
bin thnh vin trong hot ng hoc phn on ca bn c th hu ch nh th no.</p>
</li>

  <li>Gi {@link android.app.Activity#startActionMode startActionMode()}  kch hot ch  hnh ng theo ng cnh
khi ph hp, chng hn nh  hi p li mt s kin nhp gi trn mt {@link
android.view.View}:</p>

<pre>
someView.setOnLongClickListener(new View.OnLongClickListener() {
    // Called when the user long-clicks on someView
    public boolean onLongClick(View view) {
        if (mActionMode != null) {
            return false;
        }

        // Start the CAB using the ActionMode.Callback defined above
        mActionMode = getActivity().startActionMode(mActionModeCallback);
        view.setSelected(true);
        return true;
    }
});
</pre>

<p>Khi bn gi {@link android.app.Activity#startActionMode startActionMode()}, h thng s tr v
{@link android.view.ActionMode} c to. Bng cch lu iu ny trong mt bin thnh vin, bn c th
thc hin thay i thanh hnh ng theo ng cnh  hi p nhng s kin khc. Trong mu trn,
{@link android.view.ActionMode} c s dng  m bo rng thc th {@link android.view.ActionMode} khng
c to li nu n  hin hot, bng cch kim tra xem thnh vin c rng khng trc khi khi ng
ch  hnh ng.</p>
</li>
</ol>


<h4 id="CABforListView">Kch hot hnh ng theo ng cnh hng lot trong ListView hoc GridView</h4>

<p>Nu bn c mt b su tp cc mc trong mt {@link android.widget.ListView} hoc {@link
android.widget.GridView} (hoc mt phn m rng khc ca {@link android.widget.AbsListView}) v mun
cho php ngi dng thc hin cc hnh ng hng lot, bn nn:</p>

<ul>
  <li>Trin khai giao din {@link android.widget.AbsListView.MultiChoiceModeListener} v t n
cho nhm dng xem bng {@link android.widget.AbsListView#setMultiChoiceModeListener
setMultiChoiceModeListener()}. Trong cc phng php gi li ca trnh nghe, bn c th quy nh cc hnh ng
cho thanh hnh ng theo ng cnh, hi p cc s kin nhp trn cc mc hnh ng, v x l cc phng php gi li khc
c k tha t giao din {@link android.view.ActionMode.Callback}.</li>

  <li>Gi {@link android.widget.AbsListView#setChoiceMode setChoiceMode()} bng tham i {@link
android.widget.AbsListView#CHOICE_MODE_MULTIPLE_MODAL}.</li>
</ul>

<p>V d:</p>

<pre>
ListView listView = getListView();
listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);
listView.setMultiChoiceModeListener(new MultiChoiceModeListener() {

    &#64;Override
    public void onItemCheckedStateChanged(ActionMode mode, int position,
                                          long id, boolean checked) {
        // Here you can do something when items are selected/de-selected,
        // such as update the title in the CAB
    }

    &#64;Override
    public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
        // Respond to clicks on the actions in the CAB
        switch (item.getItemId()) {
            case R.id.menu_delete:
                deleteSelectedItems();
                mode.finish(); // Action picked, so close the CAB
                return true;
            default:
                return false;
        }
    }

    &#64;Override
    public boolean onCreateActionMode(ActionMode mode, Menu menu) {
        // Inflate the menu for the CAB
        MenuInflater inflater = mode.getMenuInflater();
        inflater.inflate(R.menu.context, menu);
        return true;
    }

    &#64;Override
    public void onDestroyActionMode(ActionMode mode) {
        // Here you can make any necessary updates to the activity when
        // the CAB is removed. By default, selected items are deselected/unchecked.
    }

    &#64;Override
    public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
        // Here you can perform updates to the CAB due to
        // an {@link android.view.ActionMode#invalidate} request
        return false;
    }
});
</pre>

<p>Vy l xong. Lc ny, khi ngi dng chn mt mc bng nhp gi, h thng s gi phng php {@link
android.widget.AbsListView.MultiChoiceModeListener#onCreateActionMode onCreateActionMode()}
v hin th thanh hnh ng theo ng cnh vi cc hnh ng c quy nh. Trong khi thanh hnh ng theo ng cnh
hin th, ngi dng c th chn thm mc.</p>

<p>Trong mt s trng hp m cc hnh ng ng cnh cung cp cc mc hnh ng chung, bn c th mun
thm mt hp kim hoc mt phn t UI tng t  cho php ngi dng chn cc mc, v
h c th khng pht hin c hnh vi nhp gi. Khi mt ngi dng chn hp kim, bn
c th gi ra ch  hnh ng theo ng cnh bng cch thit t mc danh sch tng ng v trng thi
 chn bng {@link android.widget.AbsListView#setItemChecked setItemChecked()}.</p>


<h2 id="PopupMenu">To mt Menu Bt ln</h2>

<div class="figure" style="width:220px">
<img src="{@docRoot}images/ui/popupmenu.png" alt="" />
<p><strong>Hnh 4.</strong> Menu bt ln trong ng dng Gmail, c neo vo nt trn
 trn cng bn phi.</p>
</div>

<p>{@link android.widget.PopupMenu} l mt menu m thi c neo vo mt {@link android.view.View}.
N xut hin bn di dng xem du neo nu c khong trng, hoc bn trn dng xem nu khng. N c ch cho vic:</p>
<ul>
  <li>Cung cp mt menu kiu trn cho cc hnh ng m <em>lin quan ti</em> ni dung c th (chng hn nh tiu  e-mail
ca Gmail nh minh ha trong hnh 4).
    <p class="note"><strong>Lu :</strong> N khng ging nh mt menu ng cnh, vn thng
p dng cho cc hnh ng m <em>nh hng</em> ti ni dung c chn. i vi nhng hnh ng nh hng ti ni dung
c chn, hy s dng <a href="#CAB">ch  hnh ng theo ng cnh</a> hoc <a href="#FloatingContextMenu">menu ng cnh ni</a>.</p></li>
  <li>Cung cp mt phn th hai ca cu lnh (chng hn nh mt nt c nh du "Thm"
c chc nng to ra mt menu bt ln vi cc ty chn "Thm" khc nhau).</li>
  <li>Cung cp mt danh sch th xung tng t nh {@link android.widget.Spinner}, n khng gi li mt
la chn lin tc.</li>
</ul>


<p class="note"><strong>Lu :</strong> {@link android.widget.PopupMenu} sn c vi API
mc 11 tr ln.</p>

<p>Nu bn nh ngha <a href="#xml">menu ca mnh trong XML</a>, sau y l cch bn c th hin th menu bt ln:</p>
<ol>
  <li>Khi to mt {@link android.widget.PopupMenu} bng hm dng ca n, c chc nng a
ng dng hin ti {@link android.content.Context} v {@link android.view.View} ti menu
m s c neo.</li>
  <li>S dng {@link android.view.MenuInflater}  bung ti nguyn menu ca bn vo i tng {@link
android.view.Menu} c tr v bi {@link
android.widget.PopupMenu#getMenu() PopupMenu.getMenu()}. Trn API mc 14 tr ln, bn c th s dng
{@link android.widget.PopupMenu#inflate PopupMenu.inflate()} thay th.</li>
  <li>Gi {@link android.widget.PopupMenu#show() PopupMenu.show()}.</li>
</ol>

<p>V d, sau y l mt nt vi thuc tnh {@link android.R.attr#onClick android:onClick} c chc nng
hin th mt menu bt ln:</p>

<pre>
&lt;ImageButton
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/ic_overflow_holo_dark"
    android:contentDescription="@string/descr_overflow_button"
    android:onClick="showPopup" />
</pre>

<p>Khi , hot ng c th hin th menu bt ln nh sau:</p>

<pre>
public void showPopup(View v) {
    PopupMenu popup = new PopupMenu(this, v);
    MenuInflater inflater = popup.getMenuInflater();
    inflater.inflate(R.menu.actions, popup.getMenu());
    popup.show();
}
</pre>

<p>Trong API mc 14 tr ln, bn c th kt hp hai dng c chc nng bung menu bng {@link
android.widget.PopupMenu#inflate PopupMenu.inflate()}.</p>

<p>Menu b b qua khi ngi dng chn mt mc hoc chm vo bn ngoi vng
menu. Bn c th lng nghe bo hiu s kin b bng cch s dng {@link
android.widget.PopupMenu.OnDismissListener}.</p>

<h3 id="PopupEvents">X l s kin nhp</h3>

<p> thc hin mt
hnh ng khi ngi dng chn mt mc menu, bn phi trin khai giao din {@link
android.widget.PopupMenu.OnMenuItemClickListener} v ng k n vi {@link
android.widget.PopupMenu} ca mnh bng cch gi {@link android.widget.PopupMenu#setOnMenuItemClickListener
setOnMenuItemclickListener()}. Khi ngi dng chn mt mc, h thng s gi lnh gi li {@link
android.widget.PopupMenu.OnMenuItemClickListener#onMenuItemClick onMenuItemClick()} trong
giao din ca bn.</p>

<p>V d:</p>

<pre>
public void showMenu(View v) {
    PopupMenu popup = new PopupMenu(this, v);

    // This activity implements OnMenuItemClickListener
    popup.setOnMenuItemClickListener(this);
    popup.inflate(R.menu.actions);
    popup.show();
}

&#64;Override
public boolean onMenuItemClick(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.archive:
            archive(item);
            return true;
        case R.id.delete:
            delete(item);
            return true;
        default:
            return false;
    }
}
</pre>


<h2 id="groups">To Nhm Menu</h2>

<p>Nhm menu l mt tp hp cc mc menu chia s nhng c im nht nh. Vi mt nhm, bn c th
:</p>
<ul>
  <li>Hin th hoc n tt c cc mc bng {@link android.view.Menu#setGroupVisible(int,boolean)
setGroupVisible()}</li>
  <li>Kch hot hoc v hiu ha tt c cc mc bng {@link android.view.Menu#setGroupEnabled(int,boolean)
setGroupEnabled()}</li>
  <li>Quy nh xem tt c cc mc c th chn hay khng bng {@link
android.view.Menu#setGroupCheckable(int,boolean,boolean) setGroupCheckable()}</li>
</ul>

<p>Bn c th to mt nhm bng cch lng cc phn t {@code &lt;item&gt;} bn trong mt phn t {@code &lt;group&gt;}
vo ti nguyn menu ca bn hoc bng cch quy nh mt ID nhm bng phng php {@link
android.view.Menu#add(int,int,int,int) add()}.</p>

<p>Sau y l mt v d v ti nguyn menu bao gm mt nhm:</p>

<pre>
&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;menu xmlns:android="http://schemas.android.com/apk/res/android"&gt;
    &lt;item android:id="@+id/menu_save"
          android:icon="@drawable/menu_save"
          android:title="@string/menu_save" /&gt;
    &lt;!-- menu group --&gt;
    &lt;group android:id="@+id/group_delete"&gt;
        &lt;item android:id="@+id/menu_archive"
              android:title="@string/menu_archive" /&gt;
        &lt;item android:id="@+id/menu_delete"
              android:title="@string/menu_delete" /&gt;
    &lt;/group&gt;
&lt;/menu&gt;
</pre>

<p>Cc mc nm trong nhm xut hin  cng cp nh mc u tin&mdash;tt c ba mc
trong menu u l cc mc ng cp. Tuy nhin, bn c th sa i cc c im ca hai
mc trong nhm bng cch tham chiu ID nhm v s dng cc phng php c lit k bn trn. H thng cng s
khng bao gi tch ring cc mc  ghp nhm. V d, nu bn khai bo {@code
android:showAsAction="ifRoom"} cho tng mc, chng s hoc u xut hin trong thanh hnh ng
hoc u xut hin trong phn trn hnh ng.</p>


<h3 id="checkable">S dng mc menu c th chn</h3>

<div class="figure" style="width:200px">
  <img src="{@docRoot}images/radio_buttons.png" height="333" alt="" />
  <p class="img-caption"><strong>Hnh 5.</strong> nh chp mn hnh mt menu con vi cc mc
c th chn.</p>
</div>

<p>Mt mc c th c ch nh mt giao din  bt v tt cc ty chn, bng cch s dng mt hp kim cho
cc ty chn c lp, hoc nt chn mt cho cc nhm
ty chn loi tr ln nhau. Hnh 5 minh ha mt menu con vi cc mc c th chn bng cc nt
 chn mt.</p>

<p class="note"><strong>Lu :</strong> Cc mc menu trong Menu Biu tng (t menu ty chn) khng th
hin th mt hp kim hay nt chn mt. Nu bn chn t cc mc trong Menu Biu tng l c th chn,
bn phi ch nh trng thi c chn bng cch tro i biu tng v/hoc vn bn
mi ln trng thi thay i mt cch th cng.</p>

<p>Bn c th nh ngha hnh vi c th chn cho cc mc menu ring l bng cch s dng thuc tnh {@code
android:checkable} trong phn t {@code &lt;item&gt;}, hoc cho ton b nhm vi
thuc tnh {@code android:checkableBehavior} trong phn t {@code &lt;group&gt;}. V
d, tt c cc mc trong nhm menu ny c th chn bng mt nt chn mt:</p>

<pre>
&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;menu xmlns:android="http://schemas.android.com/apk/res/android"&gt;
    &lt;group android:checkableBehavior="single"&gt;
        &lt;item android:id="@+id/red"
              android:title="@string/red" /&gt;
        &lt;item android:id="@+id/blue"
              android:title="@string/blue" /&gt;
    &lt;/group&gt;
&lt;/menu&gt;
</pre>

<p>Thuc tnh {@code android:checkableBehavior} chp nhn hoc:
<dl>
  <dt>{@code single}</dt>
    <dd>Ch chn c mt mc t nhm (nt chn mt)</dd>
  <dt>{@code all}</dt>
    <dd>C th chn c tt c cc mc (hp kim)</dd>
  <dt>{@code none}</dt>
    <dd>Khng chn c mc no</dd>
</dl>

<p>Bn c th p dng mt trng thi c chn mc nh cho mt mc bng cch s dng thuc tnh {@code android:checked} trong
phn t {@code &lt;item&gt;} v thay i n trong m bng phng php {@link
android.view.MenuItem#setChecked(boolean) setChecked()}.</p>

<p>Khi chn mt mc c th chn, h thng s gi phng php gi li mc c chn tng ng
(chng hn nh {@link android.app.Activity#onOptionsItemSelected(MenuItem) onOptionsItemSelected()}). Chnh
 y bn phi t trng thi ca hp kim, v hp kim hay nt chn mt u khng
t ng thay i trng thi ca n. Bn c th truy vn trng thi hin ti ca mc (nh trc khi
ngi dng chn) bng {@link android.view.MenuItem#isChecked()} v sau  t trng thi c chn bng
{@link android.view.MenuItem#setChecked(boolean) setChecked()}. V d:</p>

<pre>
&#64;Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.vibrate:
        case R.id.dont_vibrate:
            if (item.isChecked()) item.setChecked(false);
            else item.setChecked(true);
            return true;
        default:
            return super.onOptionsItemSelected(item);
    }
}
</pre>

<p>Nu bn khng t trng thi c chn bng cch ny, khi  trng thi hin th ca mc (hp kim hoc
nt chn mt) s khng
thay i khi ngi dng chn n. Khi bn t trng thi, hot ng s gi nguyn trng thi c chn
ca mc   khi ngi dng m menu sau, trng thi c chn m bn t
s c hin th.</p>

<p class="note"><strong>Lu :</strong>
Cc mc menu c th chn c ch nh s dng trn mi phin v khng c lu sau khi
ng dng b hy. Nu bn c cc ci t ng dng m bn mun lu cho ngi dng,
bn nn lu tr d liu bng cch s dng <a href="{@docRoot}guide/topics/data/data-storage.html#pref">Ty chn dng chung</a>.</p>


<h2 id="intents">Thm Mc Menu da trn  nh</h2>

<p>i khi bn s mun mt mc menu khi chy mt hot ng bng cch s dng mt {@link android.content.Intent}
(d  l mt hot ng trong ng dng ca bn hay mt ng dng khc). Khi bn bit  nh m mnh
mun s dng v c mt mc menu c th s khi to  nh, bn c th thc thi  nh
bng {@link android.app.Activity#startActivity(Intent) startActivity()} trong phng php gi li
ph hp theo mc c chn (chng hn nh lnh gi li {@link
android.app.Activity#onOptionsItemSelected(MenuItem) onOptionsItemSelected()}).</p>

<p>Tuy nhin, nu bn khng chc chn rng thit b ca ngi dng
cha mt ng dng x l  nh  th vic thm mt mc menu gi n ra c th dn n
mc menu khng hot ng, do  nh c th khng phn gii thnh mt
hot ng.  gii quyt iu ny, Android cho php bn linh hot thm cc mc menu vo menu ca mnh
khi Android tm cc hot ng trn thit b  x l  nh ca bn.</p>

<p> thm cc mc menu da trn cc hot ng sn c m chp nhn  nh:</p>
<ol>
  <li>nh ngha mt
 nh bng th loi {@link android.content.Intent#CATEGORY_ALTERNATIVE} v/hoc
{@link android.content.Intent#CATEGORY_SELECTED_ALTERNATIVE}, cng vi bt k yu cu no khc.</li>
  <li>Gi {@link
android.view.Menu#addIntentOptions(int,int,int,ComponentName,Intent[],Intent,int,MenuItem[])
Menu.addIntentOptions()}. Sau , Android tm kim bt k ng dng no c th thc hin  nh
v thm chng vo menu ca bn.</li>
</ol>

<p>Nu khng c ng dng c ci t
m tha mn  nh th khng c mc menu no c thm vo.</p>

<p class="note"><strong>Lu :</strong>
{@link android.content.Intent#CATEGORY_SELECTED_ALTERNATIVE} c s dng  x l
phn t ang c chn trn mn hnh. V vy, n ch nn c s dng khi to mt Menu trong {@link
android.app.Activity#onCreateContextMenu(ContextMenu,View,ContextMenuInfo)
onCreateContextMenu()}.</p>

<p>V d:</p>

<pre>
&#64;Override
public boolean onCreateOptionsMenu(Menu menu){
    super.onCreateOptionsMenu(menu);

    // Create an Intent that describes the requirements to fulfill, to be included
    // in our menu. The offering app must include a category value of Intent.CATEGORY_ALTERNATIVE.
    Intent intent = new Intent(null, dataUri);
    intent.addCategory(Intent.CATEGORY_ALTERNATIVE);

    // Search and populate the menu with acceptable offering applications.
    menu.addIntentOptions(
         R.id.intent_group,  // Menu group to which new items will be added
         0,      // Unique item ID (none)
         0,      // Order for the items (none)
         this.getComponentName(),   // The current activity name
         null,   // Specific items to place first (none)
         intent, // Intent created above that describes our requirements
         0,      // Additional flags to control items (none)
         null);  // Array of MenuItems that correlate to specific items (none)

    return true;
}</pre>

<p>i vi mi hot ng c tm thy m cung cp mt b lc  nh khp vi  nh c nh ngha, mt mc menu
c thm, bng cch s dng gi tr trong <code>android:label</code> ca b lc  nh lm
tiu  ca mc menu v biu tng ca ng dng lm biu tng ca mc menu. Phng php
{@link android.view.Menu#addIntentOptions(int,int,int,ComponentName,Intent[],Intent,int,MenuItem[])
addIntentOptions()} tr v s mc menu c thm.</p>

<p class="note"><strong>Lu :</strong> Khi bn gi {@link
android.view.Menu#addIntentOptions(int,int,int,ComponentName,Intent[],Intent,int,MenuItem[])
addIntentOptions()}, n s khng ch bt k v tt c cc mc menu theo nhm menu c quy nh trong tham i
u tin.</p>


<h3 id="AllowingToAdd">Cho php hot ng ca bn c thm vo cc menu khc</h3>

<p>Bn cng c th cung cp cc dch v ca hot ng ca mnh cho cc ng dng khc, v vy ng dng ca bn
c th nm trong menu ca cc ng dng khc (o ngc vai tr nu trn).</p>

<p> c nm trong menu ca ng dng khc, bn cn nh ngha mt b lc
 nh nh bnh thng, nhng m bo thm cc gi tr {@link android.content.Intent#CATEGORY_ALTERNATIVE}
v/hoc {@link android.content.Intent#CATEGORY_SELECTED_ALTERNATIVE} cho th loi
b lc  nh. V d:</p>
<pre>
&lt;intent-filter label="&#64;string/resize_image">
    ...
    &lt;category android:name="android.intent.category.ALTERNATIVE" />
    &lt;category android:name="android.intent.category.SELECTED_ALTERNATIVE" />
    ...
&lt;/intent-filter>
</pre>

<p>Tm hiu thm v vic ghi cc b lc  nh trong ti liu
<a href="/guide/components/intents-filters.html"> nh v B lc  nh</a>.</p>

<p> tham kho mt ng dng mu s dng k thut ny, hy xem m mu
<a href="{@docRoot}resources/samples/NotePad/src/com/example/android/notepad/NoteEditor.html">Note
Pad</a>.</p>