Android：我的带有 ListView 的 App Widget 未通过按钮或更新周期进行更新
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【中文标题】Android：我的带有 ListView 的 App Widget 未通过按钮或更新周期进行更新【英文标题】：Android: My App Widget with ListView is not updating via button or update period 【发布时间】：2014-02-08 20:07:45 【问题描述】：我正在使用小部件来显示 RSS 提要。提要已显示，但我无法通过单击按钮对其进行更新。在小部件配置 xml 中设置的更新周期之后，列表也不会更新。
你能帮帮我吗？
WidgetProvider
public class WidgetProvider extends AppWidgetProvider
//Tag for Logging
private static final String TAG = "Widget";
// String to be sent on Broadcast as soon as Data is Fetched
// should be included on WidgetProvider manifest intent action
// to be recognized by this WidgetProvider to receive broadcast
public static final String DATA_FETCHED = "mypackage.DATA_FETCHED";
public static final String EXTRA_LIST_VIEW_ROW_NUMBER = "mypackage.EXTRA_LIST_VIEW_ROW_NUMBER";
public static final String WIDGET_BUTTON = "mypackage.WIDGET_BUTTON";
/*
* this method is called every 30 mins (30 min =30x60x1000) as specified on widgetinfo.xml this
* method is also called on every phone reboot from this method nothing is
* updated right now but instead RetmoteFetchService class is called this
* service will fetch data,and send broadcast to WidgetProvider this
* broadcast will be received by WidgetProvider onReceive which in turn
* updates the widget
*/
@Override
public void onUpdate(Context ctxt, AppWidgetManager appWidgetManager,
int[] appWidgetIds)
Log.d(TAG, "Hello WidgetProvider onUpdate");
/*
* int[] appWidgetIds holds ids of multiple instance of your widget
* meaning you are placing more than one widgets on your homescreen
*/
for (int i = 0; i < appWidgetIds.length; ++i)
// Create an Intent for on click refresh
Intent intent = new Intent(WIDGET_BUTTON);
PendingIntent pendingIntent = PendingIntent.getBroadcast(ctxt, 0,
intent, PendingIntent.FLAG_UPDATE_CURRENT);
// Get the layout for the App Widget and attach an on-click listener
// to the button
RemoteViews remoteViews = new RemoteViews(ctxt.getPackageName(),
R.layout.widget_layout);
remoteViews.setOnClickPendingIntent(R.id.refresh_widget,
pendingIntent);
// Tell the AppWidgetManager to perform an update on the current app widget
appWidgetManager.updateAppWidget(appWidgetIds[i], remoteViews);
//start RemoteFetchService to parse XML in AsyncTask
Intent serviceIntent = new Intent(ctxt, RemoteFetchService.class);
serviceIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,
appWidgetIds[i]);
ctxt.startService(serviceIntent);
super.onUpdate(ctxt, appWidgetManager, appWidgetIds);
protected PendingIntent getPendingSelfIntent(Context context, String action)
Intent intent = new Intent(context, getClass());
intent.setAction(action);
return PendingIntent.getBroadcast(context, 0, intent, 0);
/*
* It receives the broadcast as per the action set on intent filters on
* Manifest.xml once data is fetched from RemoteFetchService,it sends
* broadcast and WidgetProvider notifies to change the data the data change
* right now happens on ListProvider as it takes RemoteFetchService
* listItemList as data
*/
@SuppressWarnings("deprecation")
@Override
public void onReceive(Context context, Intent intent)
super.onReceive(context, intent);
Log.d(TAG, "Hello WidgetProvider onReceive");
// if RSS Feed was parsed in RemoteFetchService.java
if (intent.getAction().equals(DATA_FETCHED))
Log.d(TAG, "Data fetched in Widget Provider in OnReceive");
int appWidgetId = intent.getIntExtra(
AppWidgetManager.EXTRA_APPWIDGET_ID,
AppWidgetManager.INVALID_APPWIDGET_ID);
AppWidgetManager appWidgetManager = AppWidgetManager
.getInstance(context);
// which layout to show on widget
RemoteViews remoteViews = new RemoteViews(context.getPackageName(),
R.layout.widget_layout);
// RemoteViews Service needed to provide adapter for ListView
Intent svcIntent = new Intent(context, WidgetService.class);
// passing app widget id to that RemoteViews Service
svcIntent
.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
// setting a unique Uri to the intent
svcIntent.setData(Uri.parse(svcIntent
.toUri(Intent.URI_INTENT_SCHEME)));
// setting adapter to listview of the widget
remoteViews.setRemoteAdapter(appWidgetId, R.id.listViewWidget,
svcIntent);
// setting an empty view in case of no data
remoteViews.setEmptyView(R.id.listViewWidget, R.id.empty_view);
// onclick item listview
// This section makes it possible for items to have individualized
// behavior.
// It does this by setting up a pending intent template. Individuals
// items of a collection
// cannot set up their own pending intents. Instead, the collection
// as a whole sets
// up a pending intent template, and the individual items set a
// fillInIntent
// to create unique behavior on an item-by-item basis.
Intent toastIntent = new Intent(context, WidgetProvider.class);
// Set the action for the intent.
// When the user touches a particular view, it will have the effect
// of
// broadcasting TOAST_ACTION.
toastIntent.setAction(WidgetProvider.EXTRA_LIST_VIEW_ROW_NUMBER);
toastIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,
appWidgetId);
intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME)));
PendingIntent toastPendingIntent = PendingIntent.getBroadcast(
context, 0, toastIntent, PendingIntent.FLAG_UPDATE_CURRENT);
remoteViews.setPendingIntentTemplate(R.id.listViewWidget,
toastPendingIntent);
appWidgetManager.updateAppWidget(appWidgetId, remoteViews);
//appWidgetManager.notifyAppWidgetViewDataChanged(appWidgetId, R.id.listViewWidget);
// if item on list was clicked
if (intent.getAction().equals(EXTRA_LIST_VIEW_ROW_NUMBER))
Log.d(TAG, "List Item Clicked in OnReceive in Widget Provider");
int appWidgetId = intent.getIntExtra(
AppWidgetManager.EXTRA_APPWIDGET_ID,
AppWidgetManager.INVALID_APPWIDGET_ID);
AppWidgetManager appWidgetManager = AppWidgetManager
.getInstance(context);
// get position on listview which was clicked
int position = intent.getIntExtra(EXTRA_LIST_VIEW_ROW_NUMBER, 0);
// get RSSFeed
RSSFeed feed = ListItem.Feed;
Intent toastIntent = new Intent(context, ItemDetailActivity.class);
toastIntent.setAction(WidgetProvider.EXTRA_LIST_VIEW_ROW_NUMBER);
toastIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,
appWidgetId);
/*
* Toast.makeText(context, "Clicked on position :" + viewIndex,
* Toast.LENGTH_SHORT).show();
*/
// start ItemDetailActivity
Intent detailIntent = new Intent(context, ItemDetailActivity.class);
detailIntent.putExtra("pos", position);
detailIntent.putExtra("feed", feed);
detailIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(detailIntent);
// if refresh button was pressed
if (WIDGET_BUTTON.equals(intent.getAction()))
Log.d(TAG,
"Refresh Button Clicked in OnReceive in Widget Provider");
AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
int appWidgetIds[] = appWidgetManager.getAppWidgetIds(
new ComponentName(context, WidgetProvider.class));
appWidgetManager.notifyAppWidgetViewDataChanged(appWidgetIds, R.id.listViewWidget);
else
Log.d(TAG, "No Data fetched in Widget Provider");
RemoteFetchService
public class RemoteFetchService extends Service
//Tag for Logging
private static final String TAG = "Widget";
private int appWidgetId = AppWidgetManager.INVALID_APPWIDGET_ID;
RSSFeed feed;
public Date pDate;
public static ArrayList<ListItem> listItemList;
@Override
public IBinder onBind(Intent arg0)
return null;
/*
* Retrieve appwidget id from intent it is needed to update widget later
* start Async Task
*/
@Override
public int onStartCommand(Intent intent, int flags, int startId)
Log.d(TAG, "Hello RemoteFetchService onStartCommand");
if (intent.hasExtra(AppWidgetManager.EXTRA_APPWIDGET_ID))
appWidgetId = intent.getIntExtra(
AppWidgetManager.EXTRA_APPWIDGET_ID,
AppWidgetManager.INVALID_APPWIDGET_ID);
// fetchDataFromWeb();
new AsyncLoadXMLFeed().execute();
return super.onStartCommand(intent, flags, startId);
/**
* AsyncTask which parses the xml and post it
**/
public class AsyncLoadXMLFeed extends AsyncTask<Void, Void, RSSFeed>
protected RSSFeed doInBackground(Void... params)
try
Log.d(TAG, "Starte Parsing von URL in Widget");
// Obtain feed
DOMParser myParser = new DOMParser();
feed = myParser.parseXml("http://www.test.de/feed");
Log.d(TAG,
"ItemCount Parser in Widget: " + feed.getItemCount());
return feed;
catch (Exception e)
Log.d(TAG, "Exception beim Parsen: " + e.toString());
return null;
@Override
protected void onPostExecute(RSSFeed parsed_feed)
// super.onPostExecute(result);
Log.d(TAG, "Async Parse fertig");
listItemList = new ArrayList<ListItem>();
if (feed != null)
try
int length = feed.getItemCount();
for (int i = 0; i < length; i++)
String date = calc_date_difference(feed, i);
final ListItem listItem = new ListItem();
ListItem.Feed = feed;
listItem.heading = feed.getItem(i).getTitle();
listItem.pubDate = date;
Log.d(TAG+" Heading", feed.getItem(i).getTitle());
Log.d(TAG+" PubDate", date);
listItemList.add(listItem);
catch (Exception e)
Log.d(TAG, "Exception onPostExecute: " + e.toString());
else
Log.d(TAG, "Feed in onPostExecute ist null");
// start intent and broadcast WidgetProvider, that data is fetched
Intent widgetUpdateIntent = new Intent();
widgetUpdateIntent.setAction(WidgetProvider.DATA_FETCHED);
widgetUpdateIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,
appWidgetId);
sendBroadcast(widgetUpdateIntent);
// stop service
stopSelf();
/**
* Method to calculate the time difference
**/
public String calc_date_difference(RSSFeed feed, int pos)
// calculate the time difference to the actual system time
String pubDate = feed.getItem(pos).getDate();
SimpleDateFormat df = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss Z",
Locale.ENGLISH);
try
try
pDate = df.parse(pubDate);
catch (java.text.ParseException e)
e.printStackTrace();
pubDate = "Vor " + DateUtils.getDateDifference(pDate);
return pubDate;
catch (ParseException e)
Log.e(TAG, "Error parsing date..");
return null;
列表提供者
/**
* If you are familiar with Adapter of ListView,this is the same as adapter with
* few changes
*
*/
public class ListProvider implements RemoteViewsFactory
// Tag for Logging
private static final String TAG = "Widget";
private RemoteViews views;
private Context ctxt = null;
private int appWidgetId;
private ArrayList<ListItem> listItemList = new ArrayList<ListItem>();
public ImageLoader imageLoader;
private Bitmap bmp;
public ListProvider(Context ctxt, Intent intent)
this.ctxt = ctxt;
appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,
AppWidgetManager.INVALID_APPWIDGET_ID);
if (RemoteFetchService.listItemList != null)
listItemList = (ArrayList<ListItem>) RemoteFetchService.listItemList
.clone();
else
listItemList = new ArrayList<ListItem>();
@Override
public void onCreate()
// no-op
Log.d(TAG, "Hello ListProvider onCreate");
@Override
public void onDestroy()
// no-op
@Override
public int getCount()
return listItemList.size();
/*
* Similar to getView of Adapter where instead of Viewwe return RemoteViews
*/
@Override
public RemoteViews getViewAt(int position)
final RemoteViews remoteView = new RemoteViews(ctxt.getPackageName(),
R.layout.widget_row);
ListItem listItem = listItemList.get(position);
remoteView.setTextViewText(R.id.heading, listItem.heading);
remoteView.setTextViewText(R.id.pubDate, listItem.pubDate);
// onclick item listview
Intent fillInIntent = new Intent();
fillInIntent.putExtra(WidgetProvider.EXTRA_LIST_VIEW_ROW_NUMBER,
position);
remoteView.setOnClickFillInIntent(R.id.heading, fillInIntent);
return remoteView;
@Override
public RemoteViews getLoadingView()
return (null);
@Override
public int getViewTypeCount()
return (1);
@Override
public long getItemId(int position)
return (position);
@Override
public boolean hasStableIds()
return (true);
@Override
public void onDataSetChanged()
// This code is executed if the refresh button is pressed or after the
// update period
// start RemoteFetchService to parse XML in AsyncTask
Intent serviceIntent = new Intent(ctxt, RemoteFetchService.class);
serviceIntent
.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId);
ctxt.startService(serviceIntent);
widget_provider.xml
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
android:minHeight="200dp"
android:minWidth="200dp"
android:updatePeriodMillis="30000"
android:initialLayout="@layout/widget_layout"
android:autoAdvanceViewId="@+id/words"
android:previewImage="@drawable/widget_preview"
android:resizeMode="vertical|horizontal"
/>
我希望这一切都可以帮助我。
【问题讨论】：
我不确定，但不应该在 onUpdate 中返回吗？ 在其他示例中我从未在 onUpdate 中看到 return 语句 我的意思是，如果我没记错的话，remoteViews 应该有回报 我不这么认为，看官方描述：developer.android.com/guide/topics/appwidgets/… 您是否在onReceive() 中进行了任何调试以查看您是否按预期获得了DATA_FETCHED 广播？我猜这还没有完全正确地设置广播。
【参考方案1】：
在我为您的问题提供潜在答案之前，这里有一些如何改进代码的想法（注意它们与答案相关，因为它们有助于防止错误发生）。
onReceive
当您实现 onReceive() 时，您必须记住，appWidgetIds 可以作为带有 AppWidgetManager.EXTRA_APPWIDGET_ID 的 int 或作为带有 AppWidgetManager.EXTRA_APPWIDGET_IDS 的 int 数组传递（您自己使用这两种方法）。 为了解决这个问题，我通常会这样做：
@Override
public void onReceive(Context context, Intent intent)
Bundle extras = intent.getExtras();
int invalidId = AppWidgetManager.INVALID_APPWIDGET_ID;
int appWidgetId = extras != null ? extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, invalidId) : invalidId ;
int[] appWidgetIds = extras != null ? extras.getIntArray(AppWidgetManager.EXTRA_APPWIDGET_IDS) : null;
// single appWidgetId as parameter
if (appWidgetId != AppWidgetManager.INVALID_APPWIDGET_ID)
appWidgetIds = new int[] appWidgetId;
// multiple appWidgetIds as parameter
if (appWidgetIds != null)
for (int id:appWidgetIds)
// process a single appWidgetId
onReceiveInternal(context, intent, id)
super.onReceive(context, intent);
private boolean onReceiveInternal(Context context, Intent intent, int appWidgetId)
// do your stuff for one appWidgetId
这会阻止你这样做：
if (WIDGET_BUTTON.equals(intent.getAction()))
AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
int appWidgetIds[] = appWidgetManager.getAppWidgetIds(new ComponentName(context, WidgetProvider.class));
appWidgetManager.notifyAppWidgetViewDataChanged(appWidgetIds, R.id.listViewWidget);
如果您收到针对单个 appWidgetId 的广播，则不应更新所有小部件实例。为什么不？因为您的所有小部件实例都将收到相同的广播，并且每个实例都会为其他实例调用 notifyAppWidgetViewDataChanged。如果用户将 4 个小部件实例放在主屏幕上，按下刷新按钮将触发 16 次（原文如此！）更新。
onUpdate
当您处理 DATA_FETCHED 广播时，您希望更新小部件。现在，与 onUpdate() 相比，为什么要为此使用不同的代码？他们真的应该这样做，所以我建议使用以下模式：
private void onReceiveInternal(Context context, Intent intent, int appWidgetId)
AppWidgetManager appWidgetMgr = AppWidgetManager.getInstance(context);
String action = intent.getAction();
if (DATA_FETCHED.equals(action))
onUpdateInternal(context, appWidgetMgr, appWidgetId);
// more code here
@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds)
for (int appWidgetId : appWidgetIds)
onUpdateInternal(context, appWidgetManager, appWidgetId);
startFetchService(context, appWidgetId); // here we start the service to fetch the feed
super.onUpdate(context, appWidgetManager, appWidgetIds);
private void onUpdateInternal(Context context, AppWidgetManager appWidgetManager, int appWidgetId)
// here goes the update code
这样做可以保证更新小部件的效果相同，无论是 Android 触发的更新还是在您的提要数据进入时触发的更新。我了解您希望在第一种情况下启动 fetch 服务（这很容易实现正如我上面的代码示例所示），但实际的 ui 更新应该是一样的。
现在您创建的不是相同的 RemoteView。如果它是 Android 触发的更新，那么您基本上会膨胀布局并为刷新按钮添加一个 Intent，而提要后的更新使用 RemoteViewsService 为每个列表项设置单独的 Intent。这种方法的问题在于，Android 更新会破坏各个 Intent，直到新的提要进来，并且从用户的角度来看，小部件的行为会变得不稳定。使用我的方法，显示和行为将是一致的。
清单
请确保在您的 WidgetProvider 接收器的定义中包含具有正确操作的标签，否则您将不会收到任何更新（我猜您已经拥有该标签，或者您的小部件根本不会显示任何数据）：
<receiver android:name="mypackage.WidgetProvider">
<intent-filter>
<action android:name="mypackage.DATA_FETCHED" />
<action android:name="mypackage.EXTRA_LIST_VIEW_ROW_NUMBER" />
<action android:name="mypackage.WIDGET_BUTTON" />
</intent-filter>
<meta-data
android:name="android.appwidget.provider"
android:resource="@xml/widget_provider" />
</receiver>
一个答案
您没有发布完整的代码，所以我无法运行它。没有它，我只能确定哪个部分肯定会失败，但我可能会错过其他可能无法正常工作的部分。因此，我将其声明为“一个答案”。
在收到 DATA_FETCHED 广播后创建 RemoteViews 时，您没有将 Intent 设置为刷新按钮（您在 onUpdate 中执行此操作，但在处理 DATA_FETCHED 时未调用该按钮 -> 因此我建议使用相同的更新代码以防止此类错误发生）。如果没有这个 Intent，按下刷新按钮将什么也做不了。
当然，当涉及到定期更新时，其他答案是正确的，根据这个：http://developer.android.com/reference/android/appwidget/AppWidgetProviderInfo.html#updatePeriodMillis
如果您需要更频繁的更新，请使用 AlarmManager（在 SO 上搜索代码示例）。
【讨论】：
同时我重写了我的整个小部件代码，但你给出了如此详细的答案，你值得赏金！我在你指出的代码中有很多错误！【参考方案2】：虽然这不能解决您通过按钮更新的问题，但您的updatePeriodMillis 肯定不会按预期工作。
根据AppWidgetProviderInfo 文档，最短更新周期为 30 分钟（1800000 毫秒）。您在 XML 中指定的更新周期仅为 30 秒。如果您在检查小部件之前没有等待整整 30 分钟，您将看不到任何新数据。
【讨论】：
【参考方案3】：The issue is:
您已在 xml 中指定了仅 30 秒的更新周期
android:updatePeriodMillis="30000"
您需要等待 30 分钟才能使其正常工作。 详情见链接
http://developer.android.com/reference/android/appwidget/AppWidgetProviderInfo.html#updatePeriodMillis
【讨论】：
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