在android使用篇（三） MVC模式中提到一個問題：
1) 視圖層（View）：一般採用XML文件進行界面的描述，使用的時候可以非常方便的引入，但是用xml編寫了，又需要在Acitvity聲明並且實例化，有點麻煩，考慮能否做一個類似註解實現匹配，或者寫一個類獲取xml的各個節點然後自動進行封裝，當然，這只是個想法，以後再實現。
今天終於把這個想法實現了，使用IOC註解實現對activity中控件的實例化。
先普及一下java的反射機制和註解機制的知識：
以下引用大神的兩篇文章：
JAVA反射機制
java 註解
完成後只需要： @ViewInject(id=R.id.btn1,click="btnClick") TextView btn1; 即可完成實例化，並添加點擊事件
基本思路：
一，public abstract class D3Activity extends Activity 寫一個類繼承Activity。
二，重寫 setContentView 在此方法實現註解。
三，Field[] fields = activity.getClass().getDeclaredFields(); 獲取activity中的字段屬性
四， field.getAnnotation(ViewInject.class); 獲取字段的註解屬性
五， field.set(activity,sourceView.findViewById(viewId)); 實例化控件
大功告成，到此已實現了註解實現對android中activity和xml文件的實例化問題。
另外也可以實現註解對控件的事件添加，詳細
分三個類實現：
實現註解類：
註解類可注入 id---對應xml的id，各種點擊事件，可自己定義
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@Target(ElementType.FIELD)@Retention(RetentionPolicy.RUNTIME)
public
@interface
ViewInject { public
int
id() default
0; public
String click() default
""; public
String longClick() default
""; public
String itemClick() default
""; public
String itemLongClick() default
"";} |
重寫activity類，使用反射和註解實現實例化並加入事件：
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public
abstract
class
D3Activity extends
Activity { public
void
setContentView(int
layoutResID) { super.setContentView(layoutResID); initInjectedView(this); } public
void
setContentView(View view, LayoutParams params) { super.setContentView(view,
params); initInjectedView(this); } public
void
setContentView(View view) { super.setContentView(view); initInjectedView(this); } private
void
initInjectedView(Activity activity){ initInjectedView(activity,
activity.getWindow().getDecorView()); } private
void
initInjectedView(Object activity,View sourceView){ Field[]
fields = activity.getClass().getDeclaredFields(); //獲取字段 if(fields!=null
&& fields.length>0){ for(Field
field : fields){ try
{ field.setAccessible(true);
//設爲可訪問 if(field.get(activity)!=
null
) continue; ViewInject
viewInject = field.getAnnotation(ViewInject.class); if(viewInject!=null){ int
viewId = viewInject.id(); if(viewId
== 0) viewId
= getResources().getIdentifier(field.getName(), "id",getPackageName()); if(viewId
== 0) Log.e("D3Activity",
"field
"+
field.getName() + "not
found"); //關鍵,註解初始化，相當於
backBtn = (TextView) findViewById(R.id.back_btn); field.set(activity,sourceView.findViewById(viewId));
//事件 setListener(activity,field,viewInject.click(),Method.Click); setListener(activity,field,viewInject.longClick(),Method.LongClick); setListener(activity,field,viewInject.itemClick(),Method.ItemClick); setListener(activity,field,viewInject.itemLongClick(),Method.itemLongClick); } }
catch
(Exception e) { e.printStackTrace(); } } } } private
void
setListener(Object activity,Field field,String methodName,Method method)throws
Exception{ if(methodName
== null
|| methodName.trim().length() == 0) return; Object
obj = field.get(activity); switch
(method) { case
Click: if(obj
instanceof
View){ ((View)obj).setOnClickListener(new
EventListener(activity).click(methodName)); } break; case
ItemClick: if(obj
instanceof
AbsListView){ ((AbsListView)obj).setOnItemClickListener(new
EventListener(activity).itemClick(methodName)); } break; case
LongClick: if(obj
instanceof
View){ ((View)obj).setOnLongClickListener(new
EventListener(activity).longClick(methodName)); } break; case
itemLongClick: if(obj
instanceof
AbsListView){ ((AbsListView)obj).setOnItemLongClickListener(new
EventListener(activity).itemLongClick(methodName)); } break; default: break; } } public
enum
Method{ Click,LongClick,ItemClick,itemLongClick } |
事件類： 實現了 OnClickListener, OnLongClickListener, OnItemClickListener,OnItemLongClickListener ，可以自己擴展
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public
class
EventListener implements
OnClickListener, OnLongClickListener, OnItemClickListener,OnItemLongClickListener { private
Object handler; private
String clickMethod; private
String longClickMethod; private
String itemClickMethod; private
String itemLongClickMehtod; public
EventListener(Object handler) { this.handler
= handler; } public
EventListener click(String method){ this.clickMethod
= method; return
this; } public
EventListener longClick(String method){ this.longClickMethod
= method; return
this; } public
EventListener itemLongClick(String method){ this.itemLongClickMehtod
= method; return
this; } public
EventListener itemClick(String method){ this.itemClickMethod
= method; return
this; } public
boolean
onLongClick(View v) { return
invokeLongClickMethod(handler,longClickMethod,v); } public
boolean
onItemLongClick(AdapterView<!--?--> arg0, View arg1, int
arg2,long
arg3) { return
invokeItemLongClickMethod(handler,itemLongClickMehtod,arg0,arg1,arg2,arg3); } public
void
onItemClick(AdapterView<!--?--> arg0, View arg1, int
arg2, long
arg3) { invokeItemClickMethod(handler,itemClickMethod,arg0,arg1,arg2,arg3); } public
void
onClick(View v) { invokeClickMethod(handler,
clickMethod, v); } private
static
Object invokeClickMethod(Object handler, String methodName, Object... params){ if(handler
== null)
return
null; Method
method = null; try{
method
= handler.getClass().getDeclaredMethod(methodName,View.class); if(method!=null) return
method.invoke(handler, params); else throw
new
RuntimeException("no
such method:"+methodName); }catch(Exception
e){ e.printStackTrace(); } return
null; } private
static
boolean
invokeLongClickMethod(Object handler, String methodName, Object... params){ if(handler
== null)
return
false; Method
method = null; try{
//public
boolean onLongClick(View v) method
= handler.getClass().getDeclaredMethod(methodName,View.class); if(method!=null){ Object
obj = method.invoke(handler, params); return
obj==null?false:Boolean.valueOf(obj.toString());
} else throw
new
RuntimeException("no
such method:"+methodName); }catch(Exception
e){ e.printStackTrace(); } return
false; } private
static
Object invokeItemClickMethod(Object handler, String methodName, Object... params){ if(handler
== null)
return
null; Method
method = null; try{
///onItemClick(AdapterView<!--?-->
arg0, View arg1, int arg2, long arg3) method
= handler.getClass().getDeclaredMethod(methodName,AdapterView.class,View.class,int.class,long.class); if(method!=null) return
method.invoke(handler, params); else throw
new
RuntimeException("no
such method:"+methodName); }catch(Exception
e){ e.printStackTrace(); } return
null; } private
static
boolean
invokeItemLongClickMethod(Object handler, String methodName, Object... params){ if(handler
== null)
throw
new
RuntimeException("invokeItemLongClickMethod:
handler is null :"); Method
method = null; try{
///onItemLongClick(AdapterView<!--?-->
arg0, View arg1, int arg2,long arg3) method
= handler.getClass().getDeclaredMethod(methodName,AdapterView.class,View.class,int.class,long.class); if(method!=null){ Object
obj = method.invoke(handler, params); return
Boolean.valueOf(obj==null?false:Boolean.valueOf(obj.toString()));
} else throw
new
RuntimeException("no
such method:"+methodName); }catch(Exception
e){ e.printStackTrace(); } return
false; }} |
到此已經完成了，只需要這樣即可實例化：
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public
class
MainActivity extends
D3Activity { //@ViewInject
EditText input; //id和屬性名相同，自動匹配 @ViewInject(id
= R.id.input) EditText editText; @ViewInject(click="btnClick")
TextView btn1,btn2,btn3; public
void
onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public
void
btnClick(View v){ switch
(v.getId()) { case
R.id.btn1: btn1.setText(editText.getText().toString()); Toast.makeText(getApplicationContext(),
"111",
Toast.LENGTH_SHORT).show(); break; case
R.id.btn2: Toast.makeText(getApplicationContext(),
"222",
Toast.LENGTH_SHORT).show(); break; case
R.id.btn3: Toast.makeText(getApplicationContext(),
"333",
Toast.LENGTH_SHORT).show(); break; default: break; } } } |
對應xml佈局文件：
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<!--?xml
version="1.0"
encoding="utf-8"?--><linearlayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"> <edittext
android:id="@+id/input"
android:layout_width="fill_parent"
android:layout_height="wrap_content"> <textview
android:id="@+id/btn1"
android:layout_margintop="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="設置自己"> <textview
android:id="@+id/btn2"
android:layout_margintop="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="btn2"> <textview
android:id="@+id/btn3"
android:layout_margintop="10dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="btn3"></textview></textview></textview></edittext></linearlayout> |
源碼已經放在了github，有興趣的可以去看看 ：https://github.com/mozhenhau/injectAndroid.git
