http://www.cnblogs.com/debugman/archive/2012/06/18/android.html
3.0 以後系統直接支持了ListView. 關於ListView 的國內資料匱乏,大多數例子都是轉來轉去。由於初學android, 鄙人在搜索資料的時候遇到了不少麻煩~很是鬱悶和苦惱~深感國內學習氛圍確實怪異，學習方式需要改變。應該多去查看官方文檔。。。。
話不多說，現在開始listView 實現：
這是文檔列出的支持的佈局和widget控件：
A RemoteViews object (and, consequently, an App Widget) can support the following layout classes:
And the following widget classes:
- AnalogClock
- Button
- Chronometer
- ImageButton
- ImageView
- ProgressBar
- TextView
- ViewFlipper
- ListView
- GridView
- StackView
- AdapterViewFlipper
Descendants of these classes are not supported
其中有ListView和 GridView 等控件。
android 中實現 appWidget 有自己的一套機制：
1. widget 的支持，AppWidgetProvider 類的實現。
覆蓋在 AppWidgetProvider 的 OnReceive() 函數，從android的源碼中可以知道，AppWidgetProvider 的 OnUpdate() ， OnEnable(), OnDelete() 等方法都是從 OnReceive() 方法中分配進去的。即所有的廣播先通過OnReceive()函數，再分配到OnUpdate()等函數去。
public void onReceive(Context
context, Intent intent) { //
Protect against rogue update broadcasts (not really a security issue, //
just filter bad broacasts out so subclasses are less likely to crash). String
action = intent.getAction(); if (AppWidgetManager.ACTION_APPWIDGET_UPDATE.equals(action))
{ Bundle
extras = intent.getExtras(); if (extras
!= null)
{ int[]
appWidgetIds = extras.getIntArray(AppWidgetManager.EXTRA_APPWIDGET_IDS); if (appWidgetIds
!= null &&
appWidgetIds.length > 0)
{ this.onUpdate(context,
AppWidgetManager.getInstance(context), appWidgetIds); } } } else if (AppWidgetManager.ACTION_APPWIDGET_DELETED.equals(action))
{ Bundle
extras = intent.getExtras(); if (extras
!= null &&
extras.containsKey(AppWidgetManager.EXTRA_APPWIDGET_ID)) { final int appWidgetId
= extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID); this.onDeleted(context,
new int[]
{ appWidgetId }); } } else if (AppWidgetManager.ACTION_APPWIDGET_ENABLED.equals(action))
{ this.onEnabled(context); } else if (AppWidgetManager.ACTION_APPWIDGET_DISABLED.equals(action))
{ this.onDisabled(context); }}//
END_INCLUDE(onReceive) |
注意到：
String
action = intent.getAction(); |
這裏 intent 先獲取 action, 通過action 來獲取到廣播並區分類型，所以自己定義 action 通過 PendingIntent 來實現各種跳轉~
到這裏先擺下基礎的文件吧：
這裏需要注意到的是：android中的xml 文件不能有大寫字母。區分單詞用最好用 _ 符號。否則找不到文件名。
provider_info 文件，提供 appWidget 的一些基本控制信息。
<?xml
version="1.0" encoding="utf-8"?><appwidget-provider android:minWidth
= "294dp" android:minHeight
= "367dp" android:updatePeriodMillis
= "1000" android:initialLayout
= "@layout/listview" android:background="#0000ff" > </appwidget-provider> |
listview 文件： ListView 控件就在內部：
<?xml
version="1.0" encoding="utf-8"?><RelativeLayout android:layout_width="294dp" android:layout_height="400dp"> <LinearLayout android:layout_width="fill_parent" android:layout_height="360dp" android:minHeight="100dp" android:id="@+id/listviewWrapper" > <ListView android:layout_height
= "360dp" android:layout_width
= "294dp" android:background="#000000" android:id
= "@+id/myListView" /> </LinearLayout> <Button android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_below="@id/listviewWrapper" android:layout_alignParentLeft="true" android:id="@+id/refresh" android:text="refresh" > </Button></RelativeLayout> |
下面是list_item 文件：
<?xml
version="1.0" encoding="utf-8"?><RelativeLayout android:layout_width="match_parent" android:layout_height="match_parent"> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center" android:textColor="#ff0000" android:layout_marginTop="5px" android:layout_marginBottom="5px" android:paddingBottom="25px" android:paddingTop="5px" android:textSize="60px" android:id="@+id/item" /> <ImageView android:id="@+id/imageItem" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentRight="true" android:layout_alignRight="@id/item" /></RelativeLayout> |
list 的 item 中也可以添加 ImageView 等appWidget 支持的控件。
這是manifest 問件：
<?xml
version="1.0" encoding="utf-8"?><manifest
xmlns:android="http://schemas.android.com/apk/res/android" package="com.zgc.AppWidget6" android:versionCode="1" android:versionName="1.0" > <uses-sdk
android:minSdkVersion="15" /> <application android:icon="@drawable/ic_launcher" android:label="@string/app_name" > <receiver
android:name=".MyWidgetProvider"> <meta-data
android:name="android.appwidget.provider" android:resource="@xml/provider_info" > </meta-data> <intent-filter
> <action
android:name="android.appwidget.action.APPWIDGET_UPDATE"></action>
</intent-filter> </receiver> <service
android:name=".MyWidgetService" android:permission="android.permission.BIND_REMOTEVIEWS" android:exported="false" ></service> </application> <uses-permission
android:name="android.permission.INTERNET"></uses-permission></manifest> |
其中 service 提供 name 是 MyWidgetService ，他是繼承RemoteViewsService 類。是我們需要爲 遠程 ListView 提供 數據源的服務。
RemoteViewsService的是個服務。其中：
public RemoteViewsFactory
onGetViewFactory(Intent intent) { return new ListRemoteViewsFactory(this.getApplicationContext(),
intent); } |
ListRemoteViewsFactory
這裏就充當 ListView 的數據源。 |
就好比在activity 中使用ListView 一樣。也需要通過AdapterView 來爲ListView 提供數據源。不過AdatperView中提供了每一Item的方法。
具體邏輯如圖：
下面是 service 的源代碼：
public class MyWidgetService
extends RemoteViewsService
{ @Override public RemoteViewsFactory
onGetViewFactory(Intent intent) { return new ListRemoteViewsFactory(this.getApplicationContext(),
intent); } @Override public void onCreate()
{ //
TODO Auto-generated method stub System.out.println("service
in onCreate"); super.onCreate(); } @Override public void onDestroy()
{ //
TODO Auto-generated method stub System.out.println("service
in onDestory"); super.onDestroy(); } @Override public boolean onUnbind(Intent
intent) { //
TODO Auto-generated method stub System.out.println("service
in onUnbind"); return super.onUnbind(intent); } @Override public void onRebind(Intent
intent) { //
TODO Auto-generated method stub System.out.println("service
in onRebind"); super.onRebind(intent); } @Override public void onStart(Intent
intent, int startId)
{ //
TODO Auto-generated method stub System.out.println("service
in onStart"); super.onStart(intent,
startId); } @Override public int onStartCommand(Intent
intent, int flags,
int startId)
{ //
TODO Auto-generated method stub return super.onStartCommand(intent,
flags, startId); }}<br><br> |
class ListRemoteViewsFactory
implements RemoteViewsService.RemoteViewsFactory
{ private static int mCount
= 0; private List<WidgetItem>
mWidgetItems = new ArrayList<WidgetItem>(); private List<String>
mWidgetItemsAttr= new ArrayList<String>(); private Context
mContext; private int mAppWidgetId; public static int whichPage
= 0; public static int mainPageId
= -1; public static int secPageId
= -1; public static final int mainPage
= 0; public static final int secPage
= 1; public static List<Integer>
checkPos = new ArrayList<Integer>(); //public
static int[] checkPosArr = new int[100]; public ListRemoteViewsFactory(Context
context, Intent intent){ mContext
= context; mAppWidgetId
= intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID); } @Override public void onCreate()
{ System.out.println("onCreate
in factory"); //
TODO Auto-generated method stub try { Thread.sleep(3000); }
catch (InterruptedException
e) { e.printStackTrace(); } } @Override public int getCount()
{ //
TODO Auto-generated method stub if(whichPage
== mainPage){ mCount
= mWidgetItems.size(); } else if(whichPage
== secPage){ mCount
= mWidgetItemsAttr.size(); } return mCount; } @Override public long getItemId(int position)
{ //
TODO Auto-generated method stub return position; } @Override public RemoteViews
getLoadingView() { //
TODO Auto-generated method stub System.out.println("getLoadingView"); return null; } @Override public RemoteViews
getViewAt(int position)
{ System.out.println("getViewAt"); //
TODO Auto-generated method stub RemoteViews
rv = new RemoteViews(mContext.getPackageName(),
R.layout.list_item); switch(whichPage){ case mainPage
: if(-1 ==
mainPageId){ //refresh
main page System.out.println("getViewAt
mainPage refresh"); rv.setTextViewText(R.id.item,
mWidgetItems.get(position).text); Bundle
extras = new Bundle(); extras.putInt("page",
0); extras.putInt(MyWidgetProvider.EXTRA_ITEM,
position); extras.putString("name",
mWidgetItems.get(position).text); Intent
fillInIntent = new Intent(); fillInIntent.putExtras(extras); rv.setOnClickFillInIntent(R.id.item,
fillInIntent); } else{
//refresh
to secPage list content System.out.println("getViewAt
mainPage item click"); mainPageId
= -1; } break; case secPage: if(-1 ==
secPageId){ //refresh
when click back button, but I only have one home button //refresh
second list page System.out.println("getViewAt
secPage refresh"); rv.setTextViewText(R.id.item,
mWidgetItemsAttr.get(position)); rv.setImageViewResource(R.id.imageItem,
R.drawable.checkbox); Bundle
extras = new Bundle(); extras.putInt("page",
1); extras.putInt(MyWidgetProvider.EXTRA_ITEM,
position); Intent
fillInIntent = new Intent(); fillInIntent.putExtras(extras); rv.setOnClickFillInIntent(R.id.item,
fillInIntent); rv.setOnClickFillInIntent(R.id.imageItem,
fillInIntent); } else{
//change
positon rv.setTextViewText(R.id.item,
mWidgetItemsAttr.get(position)); if(-1 !=
checkPos.indexOf(position)){ //change
list item picture to be checked rv.setImageViewResource(R.id.imageItem,
R.drawable.checkedbox); } else{ rv.setImageViewResource(R.id.imageItem,
R.drawable.checkbox); } //每一個
item 都需要從新賦值。否則會出錯！！具體原因沒有查明 Bundle
extras = new Bundle(); extras.putInt("page",
1); extras.putInt(MyWidgetProvider.EXTRA_ITEM,
position); Intent
fillInIntent = new Intent(); fillInIntent.putExtras(extras); rv.setOnClickFillInIntent(R.id.item,
fillInIntent); rv.setOnClickFillInIntent(R.id.imageItem,
fillInIntent); } break; default:
; } return rv; } @Override public int getViewTypeCount()
{ //
TODO Auto-generated method stub return 1; } @Override public boolean hasStableIds()
{ //
TODO Auto-generated method stub return true; } @Override public void onDataSetChanged()
{ //
TODO Auto-generated method stub System.out.println("onDataSetChanged"); //this
func is get data mWidgetItems.clear(); switch(whichPage){ case mainPage
: System.out.println("onDataSetChanged_mainPage"); if(-1 ==
mainPageId){ //refresh
main page try{ URL
reqURL = new URL(url); BufferedReader
br = new BufferedReader(new InputStreamReader(reqURL.openStream(),
"gbk")); StringBuffer
sb = new StringBuffer(); String
line; while(null !=
(line = br.readLine())){ sb.append(line); }
br.close(); ArrayList
<Map<String, Object>> mList= new ArrayList<Map<String,
Object>>(); JSONArray
arr_json = new JSONArray(sb.toString()); for(int i
= 0,
len = arr_json.length(); i < len; i++){ String
strName = arr_json.getJSONObject(i).getString("name"); String
strUrl = arr_json.getJSONObject(i).getString("url"); int id
= arr_json.getJSONObject(i).getInt("id"); Map<String,
Object> map = new HashMap<String,
Object>(); mWidgetItems.add(new WidgetItem(strName,
id)); map.put("name",
strName); map.put("url",
strUrl); mList.add(map);
} mCount
= mWidgetItems.size(); }catch(Exception
e){ Toast.makeText(mContext,
"can't
connect server",
Toast.LENGTH_LONG).show(); } } else{
// System.out.println("onDataSetChanged_mainPage
else"); WidgetItem
item = mWidgetItems.get(mainPageId); } System.out.println("onDataSetChanged_-1"); break; case secPage:
//here
can get more info from server, but no need to get more infomation, if(-1 ==
secPageId){ mWidgetItemsAttr.clear(); System.out.println("onDataSetChanged_secPage
-1"); mWidgetItemsAttr.add("zhang"); mWidgetItemsAttr.add("gui"); mWidgetItemsAttr.add("chuang"); mWidgetItemsAttr.add("hui"); mWidgetItemsAttr.add("cong"); mWidgetItemsAttr.add("gui"); mWidgetItemsAttr.add("chuang"); mWidgetItemsAttr.add("hui"); mWidgetItemsAttr.add("cong"); mWidgetItemsAttr.add("gui"); mWidgetItemsAttr.add("chuang"); mWidgetItemsAttr.add("hui"); mWidgetItemsAttr.add("cong"); mWidgetItemsAttr.add("cong"); } else{ System.out.println("onDataSetChanged_secPage
else"); } break; default:
return ; } } @Override public void onDestroy()
{ System.out.println("onDestory
in factory"); //
TODO Auto-generated method stub mWidgetItems.clear();
}} |
<br> |
<br>注意到幾個方法：<br>public void onDataSetChanged(){.....}<br>public RemoteViews
getViewAt(int position)
{....}<br>public int getCount()
{....}<br><br>onDateSetChanged(){...} 方法在你使用的 MyWidgetProvider 的 onReceive() 和 onUpdate() 方法中調用 |
AppWidgetManager
的實例的方法: mgr.notifyAppWidgetViewDataChanged(appIds, R.id.myListView); 來更新要求更新數據源：<br>首先就會調用 ： |
onDataSetChanged(){.....} |
然後在調用
getViewAt(int position){....}<br>其中getViewAt
的參數 position 就是你的ListView中每一項 item 的位置。從 0 計數。<br>其中你必須
override 的 getCount()方法是返回你的ListView item 的總數。這個自己必須返回自己的數據才能讓getViewAt的postion能夠計數。<br><br>你獲取數據的方式比如http從服務器獲取數據的話，就需要放在onDateSetChagged()方法裏。<br>當然
public RemoteViews
getLoadingView(){...} 也可以。不過要注意放回的是RemoteViews 就說明這是要更新界面的，這個函數的作用就是在你更新界面的時候如果耗時就會顯示 正在加載... 的默認字樣，但是你可以更改這個界面。需要返回一個 RemoteViews 類型。其中你可以使用RemoteViews 去切換自己定義的 Layout 。<br><br>關於 remoteViews 的實例的方法： |
rv.setOnClickFillInIntent(R.id.item,
fillInIntent); |
在下面會解釋。<br><br><br>下面是provider: |
public class MyWidgetProvider
extends AppWidgetProvider{ public static final String
TOAST_ACTION = "com.zgc.listwidget.TOAST_ACTION"; public static final String
EXTRA_ITEM = "com.zgc.listwidget.EXTRA_ITEM"; public static final String
TO_SITE = "com.zgc.listwidget.TO_SITE"; public static final String
SITE = "com.zgc.listwidget.SITE"; public static final String
BACK_HOME = "com.zgc.listwidget.BACK_HOME"; public static String
PicName = ""; public static final String
REFRESH = "com.zgc.listwidget.REFRESH"; public static final String
ITEM = "com.zgc.AppWidget6.ITEM"; @Override public IBinder
peekService(Context myContext, Intent service) { //
TODO Auto-generated method stub System.out.println("peekService
in provider"); return super.peekService(myContext,
service); } @Override public void onDeleted(Context
context, int[]
appWidgetIds) { //
TODO Auto-generated method stub System.out.println("onDeleted
in Provider"); super.onDeleted(context,
appWidgetIds); } @Override public void onDisabled(Context
context) { //
TODO Auto-generated method stub System.out.println("onDisabled
in Provider"); super.onDisabled(context); } @Override public void onEnabled(Context
context) { //
TODO Auto-generated method stub System.out.println("onEnabled
in Provider"); super.onEnabled(context); } @Override public void onReceive(Context
context, Intent intent) { //
TODO Auto-generated method stub AppWidgetManager
mgr = AppWidgetManager.getInstance(context); ComponentName
cmpName = new ComponentName(context,
MyWidgetProvider.class); if (intent.getAction().equals(ITEM))
{ System.out.println("item
action"); int pageNum
= intent.getIntExtra("page",
1); int itemPos
= intent.getIntExtra(EXTRA_ITEM, 0); if(0 ==
pageNum){ System.out.println("item
action 0 page"); ListRemoteViewsFactory.secPageId
= -1; ListRemoteViewsFactory.whichPage
= ListRemoteViewsFactory.secPage; int[]
appIds = mgr.getAppWidgetIds(cmpName); mgr.notifyAppWidgetViewDataChanged(appIds,
R.id.myListView); //change
refresh to commit button ,here no need to reload listview RemoteViews
rv2 = new RemoteViews(context.getPackageName(),
R.layout.listview); rv2.setTextViewText(R.id.refresh,
"commit"); Intent
commitIntent = new Intent(context,
MyWidgetProvider.class); commitIntent.setData(Uri.parse(commitIntent.toUri(Intent.URI_INTENT_SCHEME))); commitIntent.setAction(SITE); PendingIntent
commitPendingIntent = PendingIntent.getBroadcast(context, 0,
commitIntent,
PendingIntent.FLAG_UPDATE_CURRENT); rv2.setOnClickPendingIntent(R.id.refresh,
commitPendingIntent); mgr.updateAppWidget(appIds,
rv2); } else if(1 ==
pageNum){ System.out.println("item
action 1 page"); ListRemoteViewsFactory.secPageId
= itemPos; if(-1 ==
ListRemoteViewsFactory.checkPos.indexOf(itemPos)){ ListRemoteViewsFactory.checkPos.add(itemPos); } else{ ListRemoteViewsFactory.checkPos.remove(ListRemoteViewsFactory.checkPos.indexOf(itemPos)); } int[]
appIds = mgr.getAppWidgetIds(cmpName); mgr.notifyAppWidgetViewDataChanged(appIds,
R.id.myListView); } } else if(intent.getAction().equals(SITE)){ System.out.println("in
receive commit SITE action"); RemoteViews
rv = new RemoteViews(context.getPackageName(),
R.layout.img); int id
= R.drawable.uliuli; if(PicName.equals("google")){ id
= R.drawable.uliuli; } else if(PicName.equals("douban")){ id
= R.drawable.uliuli; } rv.setImageViewResource(R.id.displayImage,
id); Intent
homeIntent = new Intent(context,
MyWidgetProvider.class); homeIntent.setAction(BACK_HOME); //homeIntent.setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE); homeIntent.setData(Uri.parse(homeIntent.toUri(Intent.URI_INTENT_SCHEME))); PendingIntent
pendingIntent = PendingIntent.getBroadcast(context, 0,
homeIntent, PendingIntent.FLAG_UPDATE_CURRENT); rv.setOnClickPendingIntent(R.id.backHome,
pendingIntent); mgr.updateAppWidget(cmpName,
rv); //Toast.makeText(context,
"Touched view zhang", Toast.LENGTH_SHORT).show(); } else if(intent.getAction().equals(BACK_HOME)){ System.out.println("back_home
"); int[]
appWidgetIds = mgr.getAppWidgetIds(cmpName); //mgr.notifyAppWidgetViewDataChanged(appWidgetIds,
R.id.myListView); Intent
serviceIntent = new Intent(context,
MyWidgetService.class);
//
//intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,
appWidgetIds[i]); serviceIntent.setData(Uri.parse(serviceIntent.toUri(Intent.URI_INTENT_SCHEME))); RemoteViews
rv = new RemoteViews(context.getPackageName(),
R.layout.listview); rv.setRemoteAdapter(R.id.myListView,
serviceIntent); Intent
toastIntent = new Intent(context,
MyWidgetProvider.class); toastIntent.setAction(MyWidgetProvider.ITEM); intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME))); PendingIntent
toastPendingIntent = PendingIntent.getBroadcast(context, 0,
toastIntent, PendingIntent.FLAG_UPDATE_CURRENT); rv.setPendingIntentTemplate(R.id.myListView,
toastPendingIntent); mgr.updateAppWidget(appWidgetIds,
rv); Intent
refreshIntent = new Intent(context,
MyWidgetProvider.class); refreshIntent.setAction(REFRESH); PendingIntent
refreshPendingIntent = PendingIntent.getBroadcast(context, 0,
refreshIntent,
0); rv.setOnClickPendingIntent(R.id.refresh,
refreshPendingIntent); ListRemoteViewsFactory.whichPage
= ListRemoteViewsFactory.mainPage; ListRemoteViewsFactory.mainPageId
= -1; mgr.updateAppWidget(cmpName,
rv); mgr.notifyAppWidgetViewDataChanged(appWidgetIds,
R.id.myListView); System.out.println("zhanggui"); //Toast.makeText(context,
"Touched view back home", Toast.LENGTH_SHORT).show(); } else if(intent.getAction().equals(REFRESH)){ System.out.println("refresh
button begin"); int[]
appWidgetIds = mgr.getAppWidgetIds(cmpName); mgr.notifyAppWidgetViewDataChanged(appWidgetIds,
R.id.myListView); System.out.println("refresh
button end"); } super.onReceive(context,
intent); } @Override public void onUpdate(Context
context, AppWidgetManager appWidgetManager, int[]
appWidgetIds) { System.out.println("onUpdate"); //
TODO Auto-generated method stub for(int i
= 0;
i < appWidgetIds.length; i++){ Intent
intent = new Intent(context,
MyWidgetService.class); intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,
appWidgetIds[i]); //
When intents are compared, the extras are ignored, so we need to embed the extras //
into the data so that the extras will not be ignored. intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME))); RemoteViews
rv = new RemoteViews(context.getPackageName(),
R.layout.listview); rv.setRemoteAdapter(R.id.myListView,
intent); //rv.setEmptyView(R.id.myListView,
R.id.empty); Intent
refreshIntent = new Intent(context,
MyWidgetProvider.class); refreshIntent.setAction(REFRESH); PendingIntent
refreshPendingIntent = PendingIntent.getBroadcast(context, 0,
refreshIntent,
0); rv.setOnClickPendingIntent(R.id.refresh,
refreshPendingIntent); Intent
toastIntent = new Intent(context,
MyWidgetProvider.class); toastIntent.setAction(MyWidgetProvider.ITEM); //toastIntent.putExtra("page",
0); // main page intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME))); PendingIntent
toastPendingIntent = PendingIntent.getBroadcast(context, 0,
toastIntent, PendingIntent.FLAG_UPDATE_CURRENT); rv.setPendingIntentTemplate(R.id.myListView,
toastPendingIntent); appWidgetManager.updateAppWidget(appWidgetIds[i],
rv); } super.onUpdate(context,
appWidgetManager, appWidgetIds); }} |
首先看onUpdate() 函數，默認是從這裏先進去的：
申明intent 後使用：
intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME))); |
用：這是爲了讓 intent 能夠帶上 extras 數據一起傳遞，否則在intent的比較的過程中會被忽略掉。這裏的比較應該是在同一個代碼塊中有多個intent的時候會發生比較吧（猜測：因爲當一條邏輯執行路徑上代碼塊中只有一個Intent發送的時候能夠帶數據(不適用intent.setData函數)，但是有多個Intent的話不行）
PendingIntent 的使用不再解釋。不過這裏的 remoteView 實例使用：
rv.setPendingIntentTemplate(R.id.myListView,
toastPendingIntent); |
listView 使用 setPendingIntentTemplate 方法，當你點擊 ListView 中的任何一個item 時都會發送 toastPendingIntent ，在我們的 service 中的getViewAt() 方法中，爲每一個item 都設置了一個 intent ：
rv.setOnClickFillInIntent(R.id.item,
fillInIntent); |
其中 remoteViews 的setOnClickFillInIntent() 是將 fillIntent 合併到 toastPendingIntent 中去。就是兩個 intent 合併了。
具體的合併方法是Intent中的fillIn(..) 方法：
Intent A ： {data="foo", categories="bar"}
Intent B ： {action="gotit", data-type="some/thing", categories="one","two"}.
調用 fillIn()： A.fillIn(B, Intent.FILL_IN_DATA)
結果： A : {action="gotit", data-type="some/thing", categories="bar"}.
|
|
注意到 action 還是你在 onUpdate()中設置的 action,當然你也可以在 item 中的 fillInIntent 設置action.但是不好。
這裏可以在每個 item 的 fillInIntent 中 使用 putExtras() 方法讓Intent 帶每個item 的 位置號碼 來區分每個 item.
機制基本上已經說完，還有一點就是：
RemoteViewsService 中每次獲取數據都會重新創建 service 和 銷燬 service ，但是 RemoteViewsService.RemoteViewsFactory
的銷燬則是在 機器上把 appWidget 刪除後發生。就好像 RemoteViewsService.RemoteViewsFactory 是個數據庫。你每次去訪問這個數據源都會創建 一個 RemoteViewsService 然後銷燬。這個源於我android學習1月，也不清楚內部機制。沒仔細研究。等研究了再發文表上。
還有 AppWidgetProvider 類的實例是每發送一次 intent （即每一次 boardcast） 就新建一次，所以如果需要做 flag 來表示按鈕是否check的話，最好就先聲明爲 static 類型或者放到其他類中。
其餘的就是自己邏輯的實現：
我這裏實現了 兩個 ListView 的數據加載(通過http從服務器獲取數據)和點入每條item進入另外的頁面(這裏也是在listView上從新加載數據，但是可以區分每個Item。也可以自己加載其他的layout)。還可以實現回到第一個加載的頁面。其實可以做到回到上一個頁面。