1 page.title=S kin Nhp liu 2 parent.title=Giao din Ngi dng 3 parent.link=index.html 4 @jd:body 5 6 <div id="qv-wrapper"> 7 <div id="qv"> 8 <h2>Trong ti liu ny</h2> 9 <ol> 10 <li><a href="#EventListeners">i tng theo di S kin</a></li> 11 <li><a href="#EventHandlers">B x l S kin</a></li> 12 <li><a href="#TouchMode">Ch Cm ng</a></li> 13 <li><a href="#HandlingFocus">X l Tiu im</a></li> 14 </ol> 15 16 </div> 17 </div> 18 19 <p>Trn Android, c nhiu cch can thip vo cc s kin t tng tc ca mt ngi dng vi ng dng ca bn. 20 Khi xem xt cc s kin trong giao din ngi dng ca bn, cch tip cn l chp li s kin t 21 i tng Dng xem c th m ngi dng tng tc vi. Lp Dng xem s cung cp phng thc lm vic ny.</p> 22 23 <p>Trong cc lp Dng xem khc nhau m bn s s dng son b tr ca mnh, bn c th thy mt vi phng php gi li 24 cng khai dng nh hu ch i vi s kin UI. Nhng phng php ny c khun kh Android gi khi 25 xy ra hnh ng tng ng trn i tng . V d, khi mt Dng xem (chng hn nh mt Nt) c chm vo, 26 phng php <code>onTouchEvent()</code> c gi trn i tng . Tuy nhin, can thip vo iu ny, bn phi m rng 27 lp v khng ch phng php . Tuy nhin, vic m rng mi i tng Dng xem 28 x l mt s kin nh vy s l khng thc t. y l l do ti sao lp Dng xem cng cha 29 mt tp hp giao din lng nhau cng cc phng php gi li m bn c th nh ngha d dng hn nhiu. Nhng giao din ny, 30 c gi l <a href="#EventListeners">i tng theo di s kin</a>, l tm v bn chp li tng tc gia ngi dng vi UI ca bn.</p> 31 32 <p>Trong khi cc i tng theo di s kin s thng c s dng theo di tng tc ca ngi dng, c th 33 c lc bn mun m rng mt lp Dng xem xy dng mt thnh phn ty chnh. 34 C th l bn mun m rng lp {@link android.widget.Button} 35 khin ci g trng n tng hn. Trong trng hp ny, bn s c th nh ngha cc hnh vi s kin mc nh cho lp 36 ca mnh bng cch s dng <a href="#EventHandlers">b x l s kin</a> ca lp.</p> 37 38 39 <h2 id="EventListeners">i tng theo di S kin</h2> 40 41 <p>i tng theo di s kin l mt giao din trong lp {@link android.view.View} cha mt phng php gi li 42 n l. Nhng phng php ny s c khun kh Android gi khi Dng xem m i tng theo di 43 c ng k vi b kch khi bi tng tc gia ngi dng vi mc trong UI.</p> 44 45 <p>Trong giao din ca i tng theo di s kin l nhng phng php gi li sau:</p> 46 47 <dl> 48 <dt><code>onClick()</code></dt> 49 <dd>T {@link android.view.View.OnClickListener}. 50 Phng php ny c gi khi ngi dng chm vo mc 51 (khi ch cm ng), hoc ly tiu im vo mt mc bng phm iu hng hoc bi xoay v 52 nhn phm "enter" ph hp hoc nhn bi xoay.</dd> 53 <dt><code>onLongClick()</code></dt> 54 <dd>T {@link android.view.View.OnLongClickListener}. 55 Phng php ny c gi khi ngi gi chm v gi mc (khi ch cm ng), hoc 56 ly tiu im vo mt mc bng phm iu hng hoc bi xoay v 57 nhn v gi phm "enter" ph hp hoc nhn v gi bi xoay (trong mt giy).</dd> 58 <dt><code>onFocusChange()</code></dt> 59 <dd>T {@link android.view.View.OnFocusChangeListener}. 60 Phng php ny c gi khi ngi dng iu hng ln hoc ra khi mt mc bng cch s dng cc phm iu hng hoc bi xoay.</dd> 61 <dt><code>onKey()</code></dt> 62 <dd>T {@link android.view.View.OnKeyListener}. 63 Phng php ny c gi khi ngi dng c ly tiu im vo mt mc v nhn hoc nh phm cng trn thit b.</dd> 64 <dt><code>onTouch()</code></dt> 65 <dd>T {@link android.view.View.OnTouchListener}. 66 Phng php ny c gi khi ngi dng thc hin mt hnh ng c coi nh mt s kin chm, bao gm nhn, nh, 67 hoc bt k ng tc chuyn ng no trn mn hnh (trong ng bin ca mc ).</dd> 68 <dt><code>onCreateContextMenu()</code></dt> 69 <dd>T {@link android.view.View.OnCreateContextMenuListener}. 70 Phng php ny c gi khi mt Menu Ng cnh ang c xy dng (kt qu ca mt s kin "nhp gi" ko di). Xem phn tho lun v 71 menu ng cnh trong hng dn dnh cho nh pht trin <a href="{@docRoot}guide/topics/ui/menus.html#context-menu">Menu</a> 72 .</dd> 73 </dl> 74 75 <p>Nhng phng php ny l phng php duy nht nm trong giao din tng ng ca chng. nh ngha mt trong nhng phng php ny 76 v x l s kin ca bn, hy trin khai giao din lng nhau trong Hot ng ca bn hoc nh ngha n thnh mt lp v danh. 77 Sau , chuyn mt thc th trin khai ca bn 78 ti phng php <code>View.set...Listener()</code> tng ng. (V d, gi 79 <code>{@link android.view.View#setOnClickListener(View.OnClickListener) setOnClickListener()}</code> 80 v chuyn cho n trin khai {@link android.view.View.OnClickListener OnClickListener} ca bn.)</p> 81 82 <p>V d bn di cho bit cch ng k mt i tng theo di khi nhp cho mt Nt. </p> 83 84 <pre> 85 // Create an anonymous implementation of OnClickListener 86 private OnClickListener mCorkyListener = new OnClickListener() { 87 public void onClick(View v) { 88 // do something when the button is clicked 89 } 90 }; 91 92 protected void onCreate(Bundle savedValues) { 93 ... 94 // Capture our button from layout 95 Button button = (Button)findViewById(R.id.corky); 96 // Register the onClick listener with the implementation above 97 button.setOnClickListener(mCorkyListener); 98 ... 99 } 100 </pre> 101 102 <p>Bn cng c th thy tin hn khi trin khai OnClickListener nh mt phn trong Hot ng ca mnh. 103 Lm vy s trnh phi ti lp b sung v phn b i tng. V d:</p> 104 <pre> 105 public class ExampleActivity extends Activity implements OnClickListener { 106 protected void onCreate(Bundle savedValues) { 107 ... 108 Button button = (Button)findViewById(R.id.corky); 109 button.setOnClickListener(this); 110 } 111 112 // Implement the OnClickListener callback 113 public void onClick(View v) { 114 // do something when the button is clicked 115 } 116 ... 117 } 118 </pre> 119 120 <p>Lu rng phng php gi li <code>onClick()</code> trong v d trn khng c gi tr 121 tr v, nhng mt s phng php i tng theo di s kin khc phi tr v mt boolean. L do 122 ny ph thuc vo s kin. Vi s t s kin thc hin nh vy, sau y l l do:</p> 123 <ul> 124 <li><code>{@link android.view.View.OnLongClickListener#onLongClick(View) onLongClick()}</code> - 125 Tr v mt boolean cho bit bn x l s kin v s kin khng nn c tip tc hay khng. 126 C th, tr v <em>true</em> cho bit rng bn x l s kin v n nn dng y; 127 tr v <em>false</em> nu bn cha x l n v/hoc s kin s tip tc i vi bt k 128 i tng theo di khi nhp no khc.</li> 129 <li><code>{@link android.view.View.OnKeyListener#onKey(View,int,KeyEvent) onKey()}</code> - 130 Tr v mt boolean cho bit bn x l s kin v s kin khng nn c tip tc hay khng. 131 C th, tr v <em>true</em> s cho bit rng bn x l s kin v n nn dng y; 132 tr v <em>false</em> nu bn cha x l n v/hoc s kin s tip tc i vi bt k 133 i tng theo di trn phm no khc.</li> 134 <li><code>{@link android.view.View.OnTouchListener#onTouch(View,MotionEvent) onTouch()}</code> - 135 Tr v mt boolean cho bit i tng theo di ca bn c x l s kin ny hay khng. iu quan trng l 136 s kin ny c th c nhiu hnh ng ni tip nhau. V vy, nu bn tr v <em>false</em> khi 137 nhn c s kin hnh ng hng xung, bn s cho bit rng mnh cha x l s kin v cng 138 khng quan tm ti cc hnh ng sau t s kin ny. V th, bn s khng b gi v bt k hnh ng no khc 139 trong s kin, chng hn nh mt c ch ngn tay, hay s kin hnh ng cho s kin hng ln.</li> 140 </ul> 141 142 <p>Ghi nh rng cc s kin phm cng lun c chuyn ti Dng xem ang c ly tiu im. Chng c chuyn bt u t trn cng 143 ca phn cp Dng xem, ri xung di, ti khi chng n ch ph hp. Nu Dng xem ca bn (hoc con ca Dng xem) 144 hin c tiu im, khi bn c th thy hnh trnh ca s kin qua phng php <code>{@link android.view.View#dispatchKeyEvent(KeyEvent) 145 dispatchKeyEvent()}</code>. Mt cch khc chp li cc s kin phm bm thng qua Dng xem ca mnh, bn cng c th nhn 146 tt c s kin bn trong Hot ng ca mnh bng <code>{@link android.app.Activity#onKeyDown(int,KeyEvent) onKeyDown()}</code> 147 v <code>{@link android.app.Activity#onKeyUp(int,KeyEvent) onKeyUp()}</code>.</p> 148 149 <p>ng thi, khi ngh ti nhp liu vn bn cho ng dng ca bn, hy nh rng nhiu thit b ch c cc phng php 150 nhp liu mm. Nhng phng php nh vy khng bt buc phi da trn phm bm; mt s c th s dng nhp liu bng ging ni, vit tay, v.v. Ngay c khi 151 mt phng php nhp liu trnh by mt giao din nh bn phm, n s thng <strong>khng</strong> kch khi h s kin 152 <code>{@link android.app.Activity#onKeyDown(int,KeyEvent) onKeyDown()}</code>. Bn khng nn 153 xy dng UI yu cu kim sot cc thao tc nhn phm c th tr khi mun gii hn ng dng ca bn mt s thit b 154 c bn phm cng. C th, khng c da vo nhng phng php ny xc thc nhp liu khi ngi dng nhn phm 155 quay li; thay vo , hy s dng cc hnh ng nh {@link android.view.inputmethod.EditorInfo#IME_ACTION_DONE} bo hiu vi 156 phng php nhp liu bn k vng ng dng ca mnh s phn ng nh th no n c th thay i UI ca mnh cho c ngha. Trnh cc gi nh 157 v cch thc hot ng ca mt phng php nhp liu mm v ch tin tng n cung cp vn bn c nh dng cho ng dng ca mnh.</p> 158 159 <p class="note"><strong>Lu :</strong> Android s gi b x l s kin trc ri mi ti b x l 160 mc nh ph hp t nh ngha lp. Nh th, vic tr v <em>true</em> t nhng i tng theo di s kin ny s dng 161 vic lan truyn s kin ti i tng theo di s kin khc v cng s chn phng php gi li ti 162 b x l s kin mc nh trong Dng xem. V th, hy chc chn rng bn mun chm dt s kin khi tr v <em>true</em>.</p> 163 164 165 <h2 id="EventHandlers">B x l S kin</h2> 166 167 <p>Nu bn ang xy dng mt thnh phn ty chnh t Dng xem, khi bn s c th nh ngha mt vi phng php gi li 168 c s dng nh b x l s kin mc nh. 169 Trong ti liu v <a href="{@docRoot}guide/topics/ui/custom-components.html">Thnh phn 170 Ty chnh</a>, bn s tm hiu v mt s phng php gi li ph bin c s dng x l s kin, 171 bao gm:</p> 172 <ul> 173 <li><code>{@link android.view.View#onKeyDown}</code> - c gi khi xy ra mt s kin phm bm mi.</li> 174 <li><code>{@link android.view.View#onKeyUp}</code> - c gi khi xy ra mt s kin phm bm hng ln.</li> 175 <li><code>{@link android.view.View#onTrackballEvent}</code> - c gi khi xy ra mt s kin chuyn ng bi xoay.</li> 176 <li><code>{@link android.view.View#onTouchEvent}</code> - c gi khi xy ra mt s kin chuyn ng mn hnh cm ng.</li> 177 <li><code>{@link android.view.View#onFocusChanged}</code> - c gi khi dng xem c hoc mt tiu im.</li> 178 </ul> 179 <p>C mt s phng php khc m bn cn lu , chng khng thuc lp Dng xem, 180 nhng c th tc ng trc tip ti cch bn c th x l s kin. V th, khi qun l cc s kin phc tp hn bn trong 181 mt b tr, hy xt nhng phng php khc sau:</p> 182 <ul> 183 <li><code>{@link android.app.Activity#dispatchTouchEvent(MotionEvent) 184 Activity.dispatchTouchEvent(MotionEvent)}</code> - Phng php ny cho php {@link 185 android.app.Activity} ca bn can thip vo tt c s kin chm trc khi chng c phn phi ti ca s.</li> 186 <li><code>{@link android.view.ViewGroup#onInterceptTouchEvent(MotionEvent) 187 ViewGroup.onInterceptTouchEvent(MotionEvent)}</code> - Phng php ny cho php mt {@link 188 android.view.ViewGroup} xem s kin khi chng c phn phi ti Dng xem con.</li> 189 <li><code>{@link android.view.ViewParent#requestDisallowInterceptTouchEvent(boolean) 190 ViewParent.requestDisallowInterceptTouchEvent(boolean)}</code> - Gi phng php 191 ny trn Dng xem m cho bit rng n s khng can thip vo cc s kin chm bng <code>{@link 192 android.view.ViewGroup#onInterceptTouchEvent(MotionEvent)}</code>.</li> 193 </ul> 194 195 <h2 id="TouchMode">Ch Cm ng</h2> 196 <p> 197 Khi mt ngi dng ang iu hng trong mt giao din ngi dng bng phm hng hoc bi xoay, cn 198 ly tiu im ti cc mc c th hnh ng (nh nt) sao cho ngi dng c th thy 199 mc no s chp nhn nhp liu. Tuy nhin, nu thit b c kh nng cm ng, v ngi dng 200 bt u tng tc vi giao din bng cch chm vo n, khi khng cn cn 201 t sng mc hay ly tiu im ti mt Dng xem c th na. Do , c mt ch cho 202 tng tc c tn l "ch cm ng." 203 </p> 204 <p> 205 i vi thit b c kh nng cm ng, sau khi ngi dng chm vo mn hnh, thit b 206 s vo ch cm ng. T im ny tr i, ch nhng Dng xem m 207 {@link android.view.View#isFocusableInTouchMode} l ng mi c th ly tiu im, chng hn nh ch xem cc widget chnh sa vn bn. 208 Cc Dng xem chm c, chng hn nh nt, s khng ly c tiu im khi chm; chng s ch n gin 209 khi chy i tng theo di khi nhp ca mnh khi c nhn. 210 </p> 211 <p> 212 Bt c khi no mt ngi dng nhn phm hng hoc cun bng bi xoay, thit b s 213 thot ch cm ng, v tm mt dng xem ly tiu im. Lc ny, ngi dng c th tip tc tng tc 214 vi giao din ngi dng m khng chm vo mn hnh. 215 </p> 216 <p> 217 Trng thi ch cm ng s c duy tr trn ton b h thng (tt c ca s v hot ng). 218 truy vn trng thi hin ti, bn c th gi 219 {@link android.view.View#isInTouchMode} xem liu thit b c ang trong ch cm ng hay khng. 220 </p> 221 222 223 <h2 id="HandlingFocus">X l Tiu im</h2> 224 225 <p>Khun kh s x l chuyn ng ca tiu im thng xuyn hi p li nhp liu ca ngi dng. 226 Vic ny bao gm thay i tiu im khi Dng xem b loi b hoc n i, hoc khi Dng xem 227 mi c sn. Dng xem th hin s sn sng ly tiu im ca chng 228 thng qua phng php <code>{@link android.view.View#isFocusable()}</code>. thay i vic liu mt Dng xem c th ly 229 tiu im hay khng, hy gi <code>{@link android.view.View#setFocusable(boolean) setFocusable()}</code>. Khi trong ch cm ng, 230 bn c th truy vn xem Dng xem c cho php ly tiu im bng <code>{@link android.view.View#isFocusableInTouchMode()}</code> hay khng. 231 Bn c th thay i iu ny bng <code>{@link android.view.View#setFocusableInTouchMode(boolean) setFocusableInTouchMode()}</code>. 232 </p> 233 234 <p>Chuyn ng tiu im c da trn mt gii thut tm kim i tng gn nht theo 235 mt hng cho trc. Trong cc trng hp him gp, gii thut mc nh c th khng khp vi 236 hnh vi theo nh ca nh pht trin. Trong nhng tnh hung ny, bn c th cung cp 237 cc khng ch r rng vi cc thuc tnh XML sau trong tp b tr: 238 <var>nextFocusDown</var>, <var>nextFocusLeft</var>, <var>nextFocusRight</var>, v 239 <var>nextFocusUp</var>. Thm mt trong nhng thuc tnh ny vo Dng xem m <em>t</em> 240 tiu im ang ri khi. nh ngha gi tr ca thuc tnh l id ca Dng xem 241 <em>m</em> cn c ly tiu im. V d:</p> 242 <pre> 243 <LinearLayout 244 android:orientation="vertical" 245 ... > 246 <Button android:id="@+id/top" 247 android:nextFocusUp="@+id/bottom" 248 ... /> 249 <Button android:id="@+id/bottom" 250 android:nextFocusDown="@+id/top" 251 ... /> 252 </LinearLayout> 253 </pre> 254 255 <p>Thng thng, trong b tr thng ng ny, vic iu hng ln t Nt u tin s khng 256 i ti u ht v vic iu hng xung t Nt th hai cng vy. Gi th khi Nt trn cng 257 nh ngha Nt di cng l <var>nextFocusUp</var> (v ngc li), tiu im iu hng s 258 lun chuyn t trn-xung-di v di-ln-trn.</p> 259 260 <p>Nu bn mun khai bo mt Dng xem l c th ly tiu im trong UI ca mnh (thng thng th khng), 261 hy thm thuc tnh XML <code>android:focusable</code> vo Dng xem, trong khai bo b tr ca bn. 262 t gi tr <var>true</var>. Bn cng c th khai bo mt Dng xem 263 l c th ly tiu im trong khi Ch Cm ng bng <code>android:focusableInTouchMode</code>.</p> 264 <p> yu cu mt Dng xem c th ly tiu im, hy gi <code>{@link android.view.View#requestFocus()}</code>.</p> 265 <p> theo di cc s kin tiu im (c thng bo khi mt Dng xem nhn c hoc mt tiu im), hy s dng 266 <code>{@link android.view.View.OnFocusChangeListener#onFocusChange(View,boolean) onFocusChange()}</code>, 267 nh c cp trong phn <a href="#EventListeners">i tng theo di S kin</a> bn trn.</p> 268 269 270 271 <!-- 272 <h2 is="EventCycle">Event Cycle</h2> 273 <p>The basic cycle of a View is as follows:</p> 274 <ol> 275 <li>An event comes in and is dispatched to the appropriate View. The View 276 handles the event and notifies any listeners.</li> 277 <li>If, in the course of processing the event, the View's bounds may need 278 to be changed, the View will call {@link android.view.View#requestLayout()}.</li> 279 <li>Similarly, if in the course of processing the event the View's appearance 280 may need to be changed, the View will call {@link android.view.View#invalidate()}.</li> 281 <li>If either {@link android.view.View#requestLayout()} or {@link android.view.View#invalidate()} were called, 282 the framework will take care of measuring, laying out, and drawing the tree 283 as appropriate.</li> 284 </ol> 285 286 <p class="note"><strong>Note:</strong> The entire View tree is single threaded. You must always be on 287 the UI thread when calling any method on any View. 288 If you are doing work on other threads and want to update the state of a View 289 from that thread, you should use a {@link android.os.Handler}. 290 </p> 291 --> 292
