android 中 AppWidget 的 ListView 的实现

http://www.cnblogs.com/debugman/archive/2012/06/18/android.html

3.0 以后系统直接支持了ListView. 关于ListView 的国内资料匮乏,大多数例子都是转来转去。由于初学android, 鄙人在搜索资料的时候遇到了不少麻烦~很是郁闷和苦恼~深感国内学习氛围确实怪异，学习方式需要改变。应该多去查看官方文档。。。。

话不多说，现在开始listView 实现：

这是文档列出的支持的布局和widget控件：

A RemoteViews object (and, consequently, an App Widget) can support the following layout classes:

• FrameLayout
• LinearLayout
• RelativeLayout

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 中实现 appWidget 有自己的一套机制：

1.  widget 的支持，AppWidgetProvider 类的实现。

覆盖在 AppWidgetProvider 的 OnReceive() 函数，从android的源码中可以知道，AppWidgetProvider 的 OnUpdate() ， OnEnable(), OnDelete() 等方法都是从 OnReceive() 方法中分配进去的。即所有的广播先通过OnReceive()函数，再分配到OnUpdate()等函数去。

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();

这里 intent 先获取 action, 通过action 来获取到广播并区分类型，所以自己定义 action 通过 PendingIntent 来实现各种跳转~

到这里先摆下基础的文件吧：

这里需要注意到的是：android中的xml 文件不能有大写字母。区分单词用最好用  _  符号。否则找不到文件名。

provider_info 文件，提供 appWidget 的一些基本控制信息。

"1.0"  encoding= "utf-8" ?>

  xmlns:android= "http://schemas.android.com/apk/res/android"
  android:minWidth = "294dp"
  android:minHeight = "367dp"
  android:updatePeriodMillis = "1000"
  android:initialLayout = "@layout/listview"
  android:background= "#0000ff"
  >

listview 文件： ListView 控件就在内部：

"1.0"  encoding= "utf-8" ?>

  xmlns:android= "http://schemas.android.com/apk/res/android"
  android:layout_width= "294dp"
  android:layout_height= "400dp" >

    android:layout_width= "fill_parent"
    android:layout_height= "360dp"
    android:minHeight= "100dp"
    android:id= "@+id/listviewWrapper"
    >

        android:layout_height = "360dp"
        android:layout_width = "294dp"
        android:background= "#000000"
        android:id = "@+id/myListView"
      />


    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"
    >

下面是list_item 文件：

"1.0"  encoding= "utf-8" ?>

  xmlns:android= "http://schemas.android.com/apk/res/android"
  android:layout_width= "match_parent"
  android:layout_height= "match_parent" >

    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"
  />

    android:id= "@+id/imageItem"
    android:layout_width= "wrap_content"
    android:layout_height= "wrap_content"
    android:layout_alignParentRight= "true"
    android:layout_alignRight= "@id/item"
    />

　list 的 item 中也可以添加 ImageView 等appWidget 支持的控件。

这是manifest 问件：

"1.0"  encoding= "utf-8" ?>
"http://schemas.android.com/apk/res/android"
    package = "com.zgc.AppWidget6"
    android:versionCode= "1"
    android:versionName= "1.0"  >

    "15"  />


        android:icon= "@drawable/ic_launcher"
        android:label= "@string/app_name"  >
        ".MyWidgetProvider" >
            "android.appwidget.provider"
                android:resource= "@xml/provider_info"  >


                "android.appwidget.action.APPWIDGET_UPDATE" >



        ".MyWidgetService"
            android:permission= "android.permission.BIND_REMOTEVIEWS"
            android:exported= "false"  >



    "android.permission.INTERNET" >

其中 service 提供 name 是 MyWidgetService ，他是继承RemoteViewsService 类。是我们需要为 远程 ListView 提供 数据源的服务。

RemoteViewsService的是个服务。其中：

public  RemoteViewsFactory onGetViewFactory(Intent intent) {
      return  new  ListRemoteViewsFactory( this .getApplicationContext(), intent);
  }

ListRemoteViewsFactory 这里就充当 ListView 的数据源。

就好比在activity 中使用ListView 一样。也需要通过AdapterView 来为ListView 提供数据源。不过AdatperView中提供了每一Item的方法。

具体逻辑如图：

　　　　

 

下面是 service 的源代码：

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);
    }
}

class  ListRemoteViewsFactory implements  RemoteViewsService.RemoteViewsFactory {

    private  static  int  mCount = 0 ;
    private  List mWidgetItems = new  ArrayList();
    private  List mWidgetItemsAttr= new  ArrayList();
    private  Context mContext;
    private  int  mAppWidgetId;
    private  String url = "http://10.40.73.77/php/getData.php" ;

    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 checkPos = new  ArrayList();
    //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);
                }

                //每一个 item 都需要从新赋值。否则会出错！！具体原因没有查明
                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 > mList= new  ArrayList>();

                    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 map = new  HashMap();

                           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();
    }

}

　　

注意到几个方法： public  void  onDataSetChanged(){.....} public  RemoteViews getViewAt( int  position) {....} public  int  getCount() {....}onDateSetChanged(){...} 方法在你使用的 MyWidgetProvider 的 onReceive() 和 onUpdate() 方法中调用

AppWidgetManager 的实例的方法: mgr.notifyAppWidgetViewDataChanged(appIds, R.id.myListView); 来更新要求更新数据源：首先就会调用 ：

onDataSetChanged(){.....}

然后在调用 getViewAt( int  position){....}其中getViewAt 的参数 position 就是你的ListView中每一项 item 的位置。从 0  计数。其中你必须 override 的 getCount()方法是返回你的ListView item 的总数。这个自己必须返回自己的数据才能让getViewAt的postion能够计数。你获取数据的方式比如http从服务器获取数据的话，就需要放在onDateSetChagged()方法里。当然 public  RemoteViews getLoadingView(){...} 也可以。不过要注意放回的是RemoteViews 就说明这是要更新界面的，这个函数的作用就是在你更新界面的时候如果耗时就会显示 正在加载... 的默认字样，但是你可以更改这个界面。需要返回一个 RemoteViews 类型。其中你可以使用RemoteViews 去切换自己定义的 Layout 。关于 remoteViews 的实例的方法：