MVVM 鍜� Android Data Binding

鍦� Android 寮�鍙戣繃绋嬩腑锛岀敱浜� Android 浣滀负 View 鎻忚堪鐨� xml 瑙嗗浘鍔熻兘杈冨急锛屽紑鍙戜腑寰堝鏄撳啓鍑鸿噧鑲跨箒鏉傜殑 Activity/Fragment锛岀敋鑷虫湁鍐欏嚭杩囨暟鍗冭浠ｇ爜鐨� Activity銆傚ぇ閲忕殑鏄剧ず銆佹牎楠屻�佷簨浠跺搷搴斻�佸洖璋冩帴鍙ｅ厖鏂ュ湪 Activity 涓�侫ctivity/Fragment 瀹為檯涓婃垚浜� View 鍜� Controller 鐨勬贩鍚堜綋锛屾棦瑕佹壙鎷� View 鐨勬樉绀哄姛鑳斤紝鍙堣鎵挎媴 Controller 鐨勬帶鍒跺姛鑳姐�傛壙鎷呯殑鍔熻兘杩囧锛岃啫鑳�鎴愮箒鑺滅殑宸ㄧ被涔熷氨涓嶈冻涓烘�簡銆�

UI 鐣岄潰璁捐妯″紡

鍦ㄤ紶缁熺殑 UI 璁捐妯″紡涓紝MVC 宸茬粡瀹炶返涓瘉鏄庝簡鍏朵环鍊硷紝骞跺湪婕暱鐨勪娇鐢ㄨ繃绋嬩腑锛堬紙MVC鏈�鏃╁嚭鐜颁簬 1970 骞翠唬锛夋紨鍖栧嚭 MVP 鍜� MVVM 澶氫釜鍙樼銆�

MVC

MVC 鎴戜滑閮界煡閬撴槸 Model-View-Controller锛屼负浜嗕娇寰楃▼搴忕殑鍚勪釜閮ㄥ垎鍒嗙闄嶄綆鑰﹀悎鎬э紝MVC 闄や簡鎶婂簲鐢ㄧ▼搴忓垎鎴� View銆丮odel 灞傦紝杩橀澶栫殑鍔犱簡涓�涓� Controller 灞傦紝瀹冪殑鑱岃矗涓鸿繘琛� Model 鍜� View 涔嬮棿鐨勫崗浣滐紙璺敱銆佽緭鍏ラ澶勭悊绛夛級鐨勫簲鐢ㄩ�昏緫锛汳odel 杩涜澶勭悊涓氬姟閫昏緫銆�

MVC Pattern

MVC 閫氬父鐨勫鐞嗘椂搴忓涓嬶細

1. View 鎺ュ彈鐢ㄦ埛鐨勪氦浜掕姹傦紱
2. View 灏嗚姹傝浆浜ょ粰 Controller锛�
3. Controller 鎿嶄綔 Model 杩涜鏁版嵁鏇存柊锛�
4. 鏁版嵁鏇存柊涔嬪悗锛孧odel 閫氱煡 View 鏁版嵁鍙樺寲锛�
5. View 鏄剧ず鏇存柊涔嬪悗鐨勬暟鎹��

閫氬父 Model 浣跨敤 Observer 妯″紡閫氱煡 View 鏁版嵁鍙樺寲锛�

MVC with Observer

MVC 鐨勪紭鐐癸細

• 鎶婁笟鍔￠�昏緫鍜屽睍绀洪�昏緫鍒嗙锛屾ā鍧楀寲绋嬪害楂樸�備笖褰撳簲鐢ㄩ�昏緫闇�瑕佸彉鏇寸殑鏃跺�欙紝涓嶉渶瑕佸彉鏇翠笟鍔￠�昏緫鍜屽睍绀洪�昏緫锛屽彧闇�瑕丆ontroller鎹㈡垚鍙﹀涓�涓狢ontroller灏辫浜嗭紙Swappable Controller锛夈��
• 瑙傚療鑰呮ā寮忓彲浠ュ仛鍒板瑙嗗浘鍚屾椂鏇存柊銆�

MVD 鐨勭己鐐癸細

• Controller 娴嬭瘯鍥伴毦銆傚洜涓鸿鍥惧悓姝ユ搷浣滄槸鐢� View 鑷繁鎵ц锛岃�� View 鍙兘鍦� UI 鐜涓嬭繍琛屻�傚湪娌℃湁 UI 鐜涓嬪 Controller 杩涜鍗曞厓娴嬭瘯鐨勬椂鍊欙紝搴旂敤閫昏緫姝ｇ‘鎬ф槸鏃犳硶楠岃瘉鐨勶細Model 鏇存柊鐨勬椂鍊欙紝鏃犳硶瀵� View 鐨勬洿鏂版搷浣滆繘琛屾柇瑷�銆�
• View 鏃犳硶缁勪欢鍖栥�俈iew 鏄己渚濊禆鐗瑰畾鐨� Model 鐨勶紝濡傛灉闇�瑕佹妸杩欎釜 View 鎶藉嚭鏉ヤ綔涓轰竴涓彟澶栦竴涓簲鐢ㄧ▼搴忓彲澶嶇敤鐨勭粍浠跺氨鍥伴毦浜嗐�傚洜涓轰笉鍚岀▼搴忕殑鐨� Model 鏄笉涓�鏍风殑銆�
• 褰撴湁鍙樺寲鐨勬椂鍊欓渶瑕佸悓鏃剁淮鎶� Model, View, Controller 鍙婂叾浜や簰锛岃繖鏄剧劧璁╀簨鎯呭鏉傚寲浜嗐��

MVP

涓轰簡瑙ｅ喅 MVC 鐨勬潈闄愶紝MVP 瀵� MVC 杩涜浜嗘敼鑹紝MVP 妯″紡鎶� MVC 妯″紡涓殑 Controller 鎹㈡垚浜� Presenter锛�

MVP Pattern

MVP 閫氬父鐨勮皟鐢ㄦ椂搴忓涓嬶細

1. View 鎺ュ彈鐢ㄦ埛鐨勪氦浜掕姹傦紱
2. View 灏嗚姹傝浆浜ょ粰 Presenter锛�
3. Presenter 鎿嶄綔 Model 杩涜涓氬姟澶勭悊锛�
4. Model 閫氱煡 Presenter 鏁版嵁鍙戠敓鍙樺寲锛�
5. Presenter 鏇存柊 View 鐨勬暟鎹��

鍜� MVC 涓嶅悓鐨勬槸锛孭resenter 浼氬弽浣滅敤浜� View锛屼笉鍍� Controller 鍙兘琚姩鐨勬帴鍙� View 鐨勬寚鎸ャ��

閫氬父鎴戜滑浼氭娊璞� View 鎺ュ彛锛屾毚闇插睘鎬у拰浜嬩欢锛岀劧鍚� Presenter 寮曠敤 View 鎺ュ彛銆傝繖鏍峰彲浠ュ緢瀹规槗鐨勬瀯閫� View 鐨� Mock 瀵硅薄锛屾彁楂樺彲鍗曞厓娴嬭瘯鎬с�傚湪杩欓噷锛孭resenter 鐨勮矗浠诲彉澶т簡锛屼笉浠呰鎿嶄綔鏁版嵁锛岃�屼笖瑕佹洿鏂� View銆�

涓婇潰璁茬殑鏄� MVP 鐨� Passive View 妯″紡锛岃妯″紡涓� View 闈炲父 Passive锛屽畠鍑犱箮浠�涔堥兘涓嶇煡閬擄紝Presenter 璁╁畠骞蹭粈涔堝畠灏卞共浠�涔堛��

鍦ㄥ疄闄呯殑瀹炵幇涓紝鏈変汉浼氬�惧悜浜� 濂� Presenter 涓�閮ㄥ垎绠�鍗曠殑鍚屾閫昏緫浜ょ粰 View 鑷繁鍘诲仛锛孭resenter 鍙礋璐ｆ瘮杈冨鏉傜殑銆侀珮灞傛鐨� UI 鎿嶄綔锛屾墍浠ュ彲浠ユ妸瀹冪湅鎴愪竴涓� Supervising Controller锛岃繖绉嶆ā寮忎篃琚О涓� The Supervising Controller MVP锛�

The Supervising Controller MVP

MVP 鐨勪紭鐐癸細

• 渚夸簬娴嬭瘯銆侾resenter 瀵� View 鏄�氳繃鎺ュ彛杩涜锛屽湪瀵� Presenter 杩涜涓嶄緷璧� UI 鐜鐨勫崟鍏冩祴璇曠殑鏃跺�欍�傚彲浠ラ�氳繃 Mock 涓�涓� View 瀵硅薄锛岃繖涓璞″彧闇�瑕佸疄鐜颁簡 View 鐨勬帴鍙ｅ嵆鍙��
• View 鍙互杩涜缁勪欢鍖栥�傚湪 MVP 褰撲腑锛孷iew 涓嶄緷璧� Model銆傝繖鏍峰氨鍙互璁� View 浠庣壒瀹氱殑涓氬姟鍦烘櫙涓劚绂诲嚭鏉ワ紝鍙互璇� View 鍙互鍋氬埌瀵逛笟鍔″畬鍏ㄦ棤鐭ャ�傚畠鍙渶瑕佹彁渚涗竴绯诲垪鎺ュ彛鎻愪緵缁欎笂灞傛搷浣溿�傝繖鏍峰氨鍙互鍋氬埌楂樺害鍙鐢ㄧ殑 View缁勪欢銆�

MVP 缂虹偣锛�

• Presenter 涓櫎浜嗗簲鐢ㄩ�昏緫浠ュ锛岃繕鏈夊ぇ閲忕殑 View->Model锛孧odel->View 鐨勬墜鍔ㄥ悓姝ラ�昏緫锛岄�犳垚 Presenter 姣旇緝绗ㄩ噸锛岀淮鎶よ捣鏉ヤ細姣旇緝鍥伴毦銆�

MVVM

MVVM 鍙互鐪嬩綔鏄竴绉嶇壒娈婄殑 MVP锛圥assive View锛夋ā寮忥紝鎴栬�呰鏄 MVP 妯″紡鐨勮繘涓�姝ユ敼鑹��

MVVM 妯″紡鏈�鏃╂槸寰蒋鍏徃鎻愬嚭锛屽苟涓斾簡澶ч噺浣跨敤鍦�.NET鐨刉PF鍜孲liverlight涓��2005骞村井杞伐绋嬪笀John Gossman鍦ㄨ嚜宸辩殑鍗氬涓婇娆″叕甯冧簡MVVM妯″紡銆�

MVVM Pattern

MVVM 浠ｈ〃鐨勬槸 Model-View-ViewModel銆侻VVM 妯″紡灏� Presenter 鏀瑰悕涓� ViewModel锛屽熀鏈笂涓� MVP 妯″紡瀹屽叏涓�鑷达紝鍞竴鍖哄埆鍦ㄤ簬 ViewModel 灏嗗瘑鍒囧叧鑱旂殑 Model 鍜� View 鐨勯�昏緫鍗曠嫭鎻愬彇鍑烘潵锛岀敤鏁版嵁缁戝畾灏嗕粬浠叧鑱斿埌涓�璧枫�侻odel 鐨勬敼鍙樹細閫氳繃 ViewModel 鏉ユ槧灏勫埌 View 涓婏紝鍙嶄箣浜︾劧銆傛暟鎹粦瀹氫綘鍙互璁や负鏄� Observer 妯″紡鎴栬�呮槸 Publish/Subscribe 妯″紡锛屽師鐞嗛兘鏄负浜嗙敤涓�绉嶇粺涓�鐨勯泦涓殑鏂瑰紡瀹炵幇棰戠箒闇�瑕佽瀹炵幇鐨勬暟鎹洿鏂伴棶棰樸��

姣旇捣MVP锛孧VVM 涓嶄粎绠�鍖栦簡涓氬姟涓庣晫闈㈢殑渚濊禆鍏崇郴锛岃繕浼樺寲浜嗘暟鎹绻佹洿鏂扮殑瑙ｅ喅鏂规锛岀敋鑷冲彲浠ヨ鎻愪緵浜嗕竴绉嶆湁鏁堢殑瑙ｅ喅妯″紡銆�

MVVM 浼樼偣锛�

• 鐪佸幓浜唌odel鍙樺寲涔嬪悗鎵嬪姩淇敼view鍜寁iew鍙樺寲涔嬪悗鎵嬪姩淇敼model鐨勭箒鐞愬伐浣滐紱
• UI鍜屽姛鑳芥洿鍔犳澗鑰﹀悎浜嗭紝鍔熻兘鐨勫彲娴嬭瘯鎬у氨瓒婃潵瓒婂己銆�

MVVM 缂虹偣锛�

• 鍦ㄥ鏉傜殑鎯呭喌涓嬶紝寰堥毦棰勫厛璁捐濂借冻澶熼�氱敤鐨� ViewModel锛�
• 閫氬父浼氫緷璧栦簬鐗瑰畾鐨勬暟鎹粦瀹氭鏋讹紱

Android Data Binding

2015 Google IO 澶т細甯︽潵鐨� Data Binding 搴撲娇寰� Android 寮�鍙戣�呭彲浠ユ柟渚跨殑瀹炵幇 MVVM 鏋舵瀯妯″紡銆�

璀﹀憡锛欴ata Binding 搴撶洰鍓嶈繕鏄� Beta 鐗堟湰锛岄噰鐢ㄩ渶璋ㄦ厧銆�

浠ヤ笅澶ч儴鍒嗗唴瀹规憳褰曡嚜Data Binding锛堟暟鎹粦瀹氾級鐢ㄦ埛鎸囧崡锛屾牴鎹� Android 瀹樻柟鑻辨枃鎸囧崡 鍋氫簡涓�浜涙洿鏂般��

閰嶇疆鐜

鏈�鏂扮増鐨� Android Studio 宸茬粡鍐呯疆浜嗗 Android Data Binding 妗嗘灦鐨勬敮鎸侊紝閰嶇疆璧锋潵涔熷緢绠�鍗曪紝鍙渶瑕佸湪 app 鐨� build.gradle 鏂囦欢涓坊鍔犱笅闈㈢殑鍐呭灏卞ソ浜�

android {
    ....
    dataBinding {
        enabled = true
    }
}

Data Binding Layout 鏂囦欢

Data Binding 琛ㄨ揪寮�

Data Binding layout 鏂囦欢鏈夌偣涓嶅悓鐨勬槸锛氳捣濮嬫牴鏍囩鏄� layout锛屾帴涓嬫潵涓�涓� data 鍏冪礌浠ュ強涓�涓� view 鐨勬牴鍏冪礌銆傝繖涓� view 鍏冪礌灏辨槸浣犳病鏈変娇鐢� Data Binding鐨刲ayout鏂囦欢鐨勬牴鍏冪礌銆備妇渚嬭鏄庡涓嬶細

鍦╠ata鍐呮弿杩颁簡涓�涓悕涓簎ser鐨勫彉閲忓睘鎬э紝浣垮叾鍙互鍦ㄨ繖涓猯ayout涓娇鐢細

鍦╨ayout鐨勫睘鎬ц〃杈惧紡鍐欎綔 @{}锛屼笅闈㈡槸涓�涓� TextView 鐨� text 璁剧疆涓� user 鐨� firstName 灞炴�э細

Data Object

鍋囪浣犳湁涓�涓猽ser鐨刾lain-old Java Object锛圥OJO锛夛細

public class User {
   public final String firstName;
   public final String lastName;
   public User(String firstName, String lastName) {
       this.firstName = firstName;
       this.lastName = lastName;
   }
}

杩欎釜绫诲瀷鐨勫璞℃嫢鏈変粠涓嶆敼鍙樼殑鏁版嵁銆傚湪 app 涓畠鏄父瑙佺殑锛屽彲浠ヨ鍙栦竴娆″苟涓斾箣鍚庝粠涓嶆敼鍙樸�傚綋鐒朵篃鍙互浣跨敤 JavaBeans 瀵硅薄锛�

public class User {
   private final String firstName;
   private final String lastName;
   public User(String firstName, String lastName) {
       this.firstName = firstName;
       this.lastName = lastName;
   }
   public String getFirstName() {
       return this.firstName;
   }
   public String getLastName() {
       return this.lastName;
   }
}

浠� Data Binding 鐨勮搴︽潵鐪嬶紝杩欎袱涓被鏄瓑浠风殑銆傜敤浜� TextView 涓殑 android:text 灞炴�х殑琛ㄨ揪寮� @{user.firstName} 灏嗚闂墠鑰� POJO 瀵硅薄涓殑 firstName 鍜屽悗鑰� JavaBeans 瀵硅薄涓殑 getFirstName() 鏂规硶銆�

缁戝畾鏁版嵁

榛樿鎯呭喌涓嬶紝涓�涓� Binding 绫讳細鍩轰簬 layout 鏂囦欢鐨勫悕绉拌�屼骇鐢燂紝灏嗗叾杞崲涓� Pascal case锛堣瘧娉細棣栧瓧姣嶅ぇ鍐欑殑鍛藉悕瑙勮寖锛夊苟涓旀坊鍔� 鈥淏inding鈥� 鍚庣紑銆備笂杩扮殑 layout 鏂囦欢鏄� activity_main.xml锛屽洜姝ょ敓鎴愮殑绫诲悕鏄� ActivityMainBinding銆傛绫诲寘鍚粠 layout 灞炴�у埌 layout 鐨� Views 涓墍鏈夌殑 bindings锛堜緥濡倁ser鍙橀噺锛夛紝骞朵笖瀹冭繕鐭ラ亾濡備綍缁� Binding 琛ㄨ揪寮忓垎閰嶆暟鍊笺�傚垱寤� bindings 鐨勬渶绠�鍗曠殑鏂瑰紡鏄湪 inflating锛堣瘧娉細layout鏂囦欢涓嶢ctivity/Fragment鐨勨�滈摼鎺モ�濓級鏈熼棿濡備笅锛�

@Override
protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.main_activity);
   User user = new User("Test", "User");
   binding.setUser(user);
}

灏辨槸杩欐牱锛岃繍琛� app 鍚庯紝浣犲皢浼氱湅鍒� Test User銆傛垨鑰呬綘鍙互閫氳繃濡備笅鑾峰彇 View锛�

MainActivityBinding binding = MainActivityBinding.inflate(getLayoutInflater());

濡傛灉浣犲湪 ListView 鎴栬�� RecyclerView adapter 浣跨敤 Data Binding 鏃讹紝浣犲彲鑳戒細浣跨敤锛�

ListItemBinding binding = ListItemBinding.inflate(layoutInflater, viewGroup,
false);
//or
ListItemBinding binding = DataBindingUtil.inflate(layoutInflater, R.layout.list_item, viewGroup, false);

缁戝畾浜嬩欢

灏卞儚浣犲彲浠ュ湪xml鏂囦欢閲岄潰浣跨敤灞炴�ndroid:onClick缁戝畾Activity閲岄潰鐨勪竴涓柟娉曚竴鏍凤紝Data Binding Library 鎵╁睍浜嗘洿澶氱殑浜嬩欢鍙互鐢ㄦ潵缁戝畾鏂规硶锛屾瘮濡� View.OnLongClickListener 鏈変釜鏂规硶 onLongClick(), 浣犲氨鍙互浣跨敤 android:onLongClick 灞炴�ф潵缁戝畾涓�涓柟娉曪紝闇�瑕佹敞鎰忕殑鏄粦瀹氱殑鏂规硶鐨勭鍚嶅繀椤诲拰璇ュ睘鎬у師鏈搴旂殑鏂规硶鐨勭鍚嶅畬鍏ㄤ竴鏍凤紝鍚﹀垯缂栬瘧闃舵浼氭姤閿欍��

涓嬮潰涓句緥鏉ヨ鏄庡叿浣撴�庝箞浣跨敤锛屽厛鐪嬬敤鏉ョ粦瀹氫簨浠剁殑绫伙細

public class MyHandlers {
    public void onClickButton(View view) { ... }

    public void afterFirstNameChanged(Editable s) { ... }
}

鐒跺悗灏辨槸layout鏂囦欢锛�

娣卞叆 Layout 鏂囦欢

Import

闆朵釜鎴栧涓� import 鍏冪礌鍙兘鍦� data 鍏冪礌涓娇鐢ㄣ�傝繖浜涘彧鐢ㄥ湪浣犵殑 layout 鏂囦欢涓坊鍔犲紩鐢紝灏卞儚鍦� Java 涓細

鐜板湪锛孷iew 鍙互浣跨敤浣犵殑 Binding 琛ㄨ揪寮忥細

褰撶被鍚嶆湁鍐茬獊鏃讹紝鍏朵腑涓�涓被鍚嶅彲浠ラ噸鍛藉悕涓篴lias:锛�

杩欐牱锛屽湪璇� layout 鏂囦欢涓� Vista 瀵瑰簲 com.example.real.estate.View锛岃�孷iew瀵瑰簲android.view.View銆傚鍏ョ殑绫诲瀷鍙互鍦╒ariable鍜岃〃杈惧紡涓娇鐢ㄤ綔涓哄紩鐢ㄦ潵浣跨敤锛�

娉ㄦ剰锛欰ndroid Studio杩樻病鏈夊鐞唅mports锛屾墍浠ヨ嚜鍔ㄥ鍏ariable鍦ㄤ綘鐨処DE涓嶈兘浣跨敤銆傛偍鐨刟pp浠嶄細姝ｅ父缂栬瘧锛屼綘鍙互鍦ㄦ偍鐨刅ariable瀹氫箟涓娇鐢ㄥ畬鍏ㄧ鍚堣瀹氱殑鍚嶇О鏉ヨВ鍐宠IDE闂銆�

瀵煎叆鐨勭被鍨嬭繕鍙互鍦ㄨ〃杈惧紡涓娇鐢� static 灞炴�у拰鏂规硶锛�

    
    

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灏卞儚鍦↗ava涓紝java.lang銆�*鏄嚜鍔ㄥ鍏ョ殑銆�

Variables

鍦╠ata涓彲浠ヤ娇鐢ㄤ换鎰忔暟閲忕殑variable鍏冪礌銆傛瘡涓�涓獀ariable鍏冪礌鎻忚堪浜嗕竴涓敤浜巐ayout鏂囦欢涓瑽inding琛ㄨ揪寮忕殑灞炴�с��

璇ariable绫诲瀷鍦ㄧ紪璇戞椂妫�鏌ワ紝鍥犳濡傛灉涓�涓猇ariable瀹炵幇浜哋bservable鎴杘bservable collection锛岃繖搴旇鍙嶆槧鍦ㄧ被鍨嬩腑銆傦紙璇戞敞锛氶渶瑕佹煡鎵捐祫鏂欐潵鐞嗚В锛夊鏋渧ariable鏄竴涓病鏈夊疄鐜癘bservable鎺ュ彛鐨勫熀鏈被鎴栬�呮帴鍙ｏ紝Variables涓嶄細琚玱bserved锛�

褰撳浜庡绉嶉厤缃湁涓嶅悓鐨刲ayout鏂囦欢鏃讹紙濡傦紝妯悜鎴栫旱鍚戯級锛孷ariables浼氳鍚堝苟銆傝繖浜沴ayout鏂囦欢涔嬮棿蹇呴』涓嶈兘鏈夊啿绐佺殑Variable瀹氫箟銆�

浜х敓鐨凚inding绫诲浜庢瘡涓�涓弿杩扮殑Variables閮戒細鏈塻etter鍜実etter銆傝繖浜沄ariables浼氫娇鐢ㄩ粯璁ょ殑Java鍊� - null锛堝紩鐢ㄧ被鍨嬶級銆�0锛坕nt锛夈�乫alse锛坆oolean锛夌瓑绛夛紝鐩村埌璋冪敤setter鏃躲��

鑷畾涔� Binding 绫诲悕绉�

榛樿鎯呭喌涓嬶紝Binding绫荤殑鍛藉悕鏄熀浜庢墍杩發ayout鏂囦欢鐨勫悕绉帮紝鐢ㄥぇ鍐欏紑澶达紝闄ゅ幓涓嬪垝绾匡紙锛変互鍙婏紙锛夊悗鐨勭涓�涓瓧姣嶅ぇ鍐欙紝鐒跺悗娣诲姞鈥淏inding鈥濆悗缂�銆傝繖涓被灏嗚鏀剧疆鍦ㄤ竴涓ā鍧楀皝瑁呭寘閲岀殑databinding灏佽鍖呬笅銆備緥濡傦紝鎵�杩發ayout鏂囦欢contact_item.xml灏嗙敓鎴怌ontactItemBinding銆傚鏋滄ā鍧楀寘鏄痗om.example.my.app锛岄偅涔堝畠灏嗚鏀剧疆鍦╟om.example.my.app.databinding銆�

Binding绫诲彲閫氳繃璋冩暣data鍏冪礌涓殑class灞炴�ф潵閲嶅懡鍚嶆垨鏀剧疆鍦ㄤ笉鍚岀殑鍖呬腑銆備緥濡傦細

    ...

鍦ㄦā鍧楀皝瑁呭寘鐨刣atabinding鍖呬腑浼氱敓鎴愬悕涓篊ontactItem鐨凚inding绫汇�傚鏋滆鎯宠璇ョ被鐢熸垚鍦ㄤ笉鍚岀殑鍖呯锛屼綘闇�瑕佹坊鍔犲墠缂�.锛屽涓嬶細

    ...

鍦ㄨ繖涓儏鍐典笅锛孋ontactItem绫荤洿鎺ュ湪妯″潡鍖呯鐢熸垚銆傛垨鑰呬綘鍙互鎻愪緵鏁翠釜鍖呭悕锛�

    ...

Includes

閫氳繃浣跨敤application namespace浠ュ強鍦ㄥ睘鎬т腑鐨刅ariable鍚嶅瓧浠庡鍣╨ayout涓紶閫扸ariables鍒颁竴涓鍖呭惈鐨刲ayout锛�

娉ㄦ剰锛氬湪name.xml浠ュ強contact.xml涓や釜layout鏂囦欢涓繀闇�瑕佹湁user variable

Data binding 涓嶆敮鎸佸寘鍚� merge 鍏冪礌浣滀负鐩存帴鐨勫瓙鍏冪礌锛屾瘮濡備互涓媗ayout鏄笉鏀寔鐨勶細

琛ㄨ揪寮忚瑷�

甯哥敤琛ㄨ揪寮忚窡Java琛ㄨ揪寮忓緢鍍忥紝浠ヤ笅杩欎簺鏄竴鏍风殑锛�

• 鏁板琛ㄨ揪寮� + 鈥� / * %
• 瀛楃涓查摼鎺� +
• 閫昏緫鎿嶄綔绗� && ||
• 浜屽厓鎿嶄綔绗� & | ^
• 涓�鍏冩搷浣滅 + 鈥� ! ~
• Shift >> >>> <<
• 姣旇緝 == > < >= <=
• instanceof
• Grouping ()
• Literals 鈥� character, String, numeric, null
• Cast
• 鍑芥暟璋冪敤
• 鍊煎煙寮曠敤锛團ield access锛�
• 閫氳繃[]璁块棶鏁扮粍閲岄潰鐨勫璞�
• 涓夊厓鎿嶄綔绗� ?:

绀轰緥锛�

android:text="@{String.valueOf(index + 1)}"
android:visibility="@{age < 13 ? View.GONE : View.VISIBLE}"
android:transitionName='@{"image_" + id}'

缂哄皯鐨勬搷浣滐細

• this
• super
• new
• 鏄惧紡娉涘瀷璋冪敤

Null鍚堝苟鎿嶄綔

?? - 宸﹁竟鐨勫璞″鏋滃畠涓嶆槸null锛岄�夋嫨宸﹁竟鐨勫璞★紱鎴栬�呭鏋滃畠鏄痭ull锛岄�夋嫨鍙宠竟鐨勫璞★細

android:text="@{user.displayName ?? user.lastName}"

鍑芥暟涓婄殑鍐欐硶濡備笅锛�

android:text="@{user.displayName != null ? user.displayName : user.lastName}"

灞炴�у紩鐢�

鎴戜滑宸茬粡鍦ㄥ墠杈光�淒ata Binding琛ㄨ揪寮忊�濅腑鎻愬埌浜咼avaBean寮曠敤鐨勭畝鐭牸寮忋��

褰撲竴涓〃杈惧紡寮曠敤涓�涓被鐨勫睘鎬э紝瀹冧粛浣跨敤鍚屾牱鐨勬牸寮忓浜庡瓧娈点�乬etters浠ュ強ObservableFields銆�

android:text="@{user.lastName}"

閬垮厤 NullPointerException

Data Binding浠ｇ爜鐢熸垚鏃惰嚜鍔ㄦ鏌ユ槸鍚︿负nulls鏉ラ伩鍏嶅嚭鐜皀ull pointer exceptions閿欒銆備緥濡傦紝鍦ㄨ〃杈惧紡@{user.name}涓紝濡傛灉user鏄痭ull锛�user.name浼氳祴浜堝畠鐨勯粯璁ゅ�硷紙null锛夈�傚鏋滀綘寮曠敤user.age锛宎ge鏄痠nt绫诲瀷锛岄偅涔堝畠鐨勯粯璁ゅ�兼槸0銆�

闆嗗悎

甯哥敤鐨勯泦鍚堬細arrays銆乴ists銆乻parse lists浠ュ強maps锛屼负浜嗙畝渚块兘鍙互浣跨敤[]鏉ヨ闂��

    
    
    
    
    
    
    
    

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android:text="@{list[index]}"
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android:text="@{sparse[index]}"
鈥�
android:text="@{map[key]}"

瀛楃涓�

褰撲娇鐢ㄥ崟寮曞彿鍖呭惈灞炴�у�兼椂锛屽湪琛ㄨ揪寮忎腑浣跨敤鍙屽紩鍙峰緢瀹规槗锛�

android:text='@{map["firstName"]}'

浣跨敤鍙屽紩鍙锋潵鍖呭惈灞炴�у�间篃鏄彲浠ョ殑銆傚瓧绗︿覆鍓嶅悗闇�瑕佷娇鐢�"`"锛�

android:text="@{map[`firstName`]}"
android:text="@{map["firstName"]}"

Resources

浣跨敤姝ｅ父鐨勮〃杈惧紡鏉ヨ闂畆esources涔熸槸鍙鐨勶細

android:padding="@{large? @dimen/largePadding : @dimen/smallPadding}"

鏍煎紡鍖栧瓧绗︿覆鍜屽鏁板彲浠ラ�氳繃鎻愪緵鍙傛暟鏉ュ垽鏂�

android:text="@{@string/nameFormat(firstName, lastName)}"
android:text="@{@plurals/banana(bananaCount)}"

褰撳鏁伴渶瑕佸涓弬鏁版椂锛屾墍鏈夌殑鍙傛暟閮戒細閫氳繃锛�

  Have an orange
  Have %d oranges

android:text="@{@plurals/orange(orangeCount, orangeCount)}"

涓�浜涜祫婧愰渶瑕佹樉寮忕被鍨嬪垽鏂細

Type	Normal Reference	Expression Reference
String[]	@array	@stringArray
int[]	@array	@intArray
TypedArray	@array	@typedArray
Animator	@animator	@animator
StateListAnimator	@animator	@stateListAnimator
color int	@color	@color
ColorStateList	@color	@colorStateList

Data Object

浠讳綍Plain old Java object锛圥O鈥嬧�婮O锛夊彲鐢ㄤ簬Data Binding锛屼絾淇敼POJO涓嶄細瀵艰嚧UI鏇存柊銆侱ata Binding鐨勭湡姝ｈ兘鍔涙槸褰撴暟鎹彉鍖栨椂锛屽彲浠ラ�氱煡缁欎綘鐨凞ata瀵硅薄銆傛湁涓夌涓嶅悓鐨勬暟鎹彉鍖栭�氱煡鏈哄埗锛歄bservable瀵硅薄銆丱bservableFields浠ュ強observable collections銆�

褰撹繖浜涘彲瑙傚療Data瀵硅薄鈥嬧�嬬粦瀹氬埌UI锛孌ata瀵硅薄灞炴�х殑鏇存敼鍚庯紝UI涔熷皢鑷姩鏇存柊銆�

Observable 瀵硅薄

瀹炵幇android.databinding.Observable鎺ュ彛鐨勭被鍙互鍏佽闄勫姞涓�涓洃鍚櫒鍒癇ound瀵硅薄浠ヤ究鐩戝惉瀵硅薄涓婄殑鎵�鏈夊睘鎬х殑鍙樺寲銆�

Observable鎺ュ彛鏈変竴涓満鍒舵潵娣诲姞鍜屽垹闄ょ洃鍚櫒锛屼絾閫氱煡涓庡惁鐢卞紑鍙戜汉鍛樼鐞嗐�備负浜嗕娇寮�鍙戞洿瀹规槗锛屼竴涓狟aseObservable鐨勫熀绫讳负瀹炵幇鐩戝惉鍣ㄦ敞鍐屾満鍒惰�屽垱寤恒�侱ata瀹炵幇绫讳緷鐒惰礋璐ｉ�氱煡褰撳睘鎬ф敼鍙樻椂銆傝繖鏄�氳繃鎸囧畾涓�涓狟indable娉ㄨВ缁檊etter浠ュ強setter鍐呴�氱煡鏉ュ畬鎴愮殑銆�

private static class User extends BaseObservable {
   private String firstName;
   private String lastName;
   @Bindable
   public String getFirstName() {
       return this.firstName;
   }
   @Bindable
   public String getFirstName() {
       return this.lastName;
   }
   public void setFirstName(String firstName) {
       this.firstName = firstName;
       notifyPropertyChanged(BR.firstName);
   }
   public void setLastName(String lastName) {
       this.lastName = lastName;
       notifyPropertyChanged(BR.lastName);
   }
}

鍦ㄧ紪璇戞湡闂达紝Bindable娉ㄨВ鍦˙R绫绘枃浠朵腑鐢熸垚涓�涓狤ntry銆侭R绫绘枃浠朵細鍦ㄦā鍧楀寘鍐呯敓鎴愩�傚鏋滅敤浜嶥ata绫荤殑鍩虹被涓嶈兘鏀瑰彉锛孫bservable鎺ュ彛閫氳繃鏂逛究鐨凱ropertyChangeRegistry鏉ュ疄鐜扮敤浜庡偍瀛樺拰鏈夋晥鍦伴�氱煡鐩戝惉鍣ㄣ��

Observable 瀛楁

涓�浜涘皬宸ヤ綔浼氭秹鍙婂埌鍒涘缓Observable绫伙紝鍥犳閭ｄ簺鎯宠鑺傜渷鏃堕棿鎴栬�呭嚑涔庢病鏈夊嚑涓睘鎬х殑寮�鍙戣�呭彲浠ヤ娇鐢∣bservableFields銆侽bservableFields鏄嚜鍖呭惈鍏锋湁鍗曚釜瀛楁鐨刼bservable瀵硅薄銆傚畠鏈夋墍鏈夊熀鏈被鍨嬪拰涓�涓槸寮曠敤绫诲瀷銆傝浣跨敤瀹冮渶瑕佸湪data瀵硅薄涓垱寤簆ublic final瀛楁锛�

private static class User extends BaseObservable {
   public final ObservableField firstName =
       new ObservableField<>();
   public final ObservableField lastName =
       new ObservableField<>();
   public final ObservableInt age = new ObservableInt();
}

灏辨槸杩欐牱锛岃璁块棶璇ュ�硷紝浣跨敤set鍜実et鏂规硶锛�

user.firstName.set("Google");
int age = user.age.get();

鍦ㄥ疄璺佃繃绋嬩腑锛屾湁鏃� notifyPropertyChanged(BR.lastName); 寰堝鏄撳紩鐢ㄩ敊璇紝鍥犳锛屽紑鍙戣繃绋嬩腑杩樻槸鎺ㄨ崘浣跨敤 ObservableField銆�

Observable 闆嗗悎

涓�浜沘pp浣跨敤鏇村鐨勫姩鎬佺粨鏋勬潵淇濆瓨鏁版嵁銆侽bservable闆嗗悎鍏佽閿帶璁块棶杩欎簺data瀵硅薄銆侽bservableArrayMap鐢ㄤ簬閿槸寮曠敤绫诲瀷,濡係tring銆�

ObservableArrayMap user = new ObservableArrayMap<>();
user.put("firstName", "Google");
user.put("lastName", "Inc.");
user.put("age", 17);

鍦╨ayout鏂囦欢涓紝閫氳繃String閿彲浠ヨ闂甿ap锛�

    
    

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ObservableArrayList 鍦ㄦ暣褰㈤敭鍊煎緢鏈夌敤锛�

ObservableArrayList