如何从活动中使用列表视图更新应用程序小部件

我知道这个问题已经被问过很多次了，但我从上到下浏览了文档，阅读了这里的所有答案，但没有一个有帮助。 老实说，每个答案对于如何解决这个问题都有不同的说法。

现在回到我的问题。我想从某些活动更新小部件列表视图，我创建了WidgetProvider#sendUpdateBroadcastToAllWidgets()为此目的，我从活动中调用了这一点。

它最终调用onUpdate()所以广播被正确接收。但视图并没有刷新。

我也尝试打电话AppWidgetManager#notifyAppWidgetViewDataChanged()并刷新了数据WidgetFactory#onDataSetChanged()但该方法从未被调用过。

所以我想这一切都不起作用，因为远程视图工厂被缓存，但我不知道如何可靠地克服这个问题。有什么想法吗？

那么上下文又如何呢？我总是必须提供一份，但我不太关心是哪一份。有关系吗？

Thanks

PROVIDER

public class WidgetProvider extends AppWidgetProvider {

    public static void sendUpdateBroadcastToAllWidgets(Context context) {
        int allWidgetIds[] = AppWidgetManager.getInstance(context).getAppWidgetIds(new ComponentName(context, WidgetProvider.class));
        Intent intent = new Intent(context, WidgetProvider.class);
        intent.setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
        intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, allWidgetIds);
        context.sendBroadcast(intent);
    }

    @Override
    public void onUpdate(Context context, AppWidgetManager widgetManager, int[] widgetIds) {
        for (int id : widgetIds) {
            updateWidget(context, widgetManager, id);
        }
        super.onUpdate(context, widgetManager, widgetIds);
    }

    @Override
    public void onDeleted(Context context, int[] widgetIds) {
        WidgetPreferences prefs = new WidgetPreferences(context);
        for (int widgetId : widgetIds) {
            prefs.getWidgetPreferences(widgetId).edit().clear().commit();
        }
        super.onDeleted(context, widgetIds);
    }

    private static void updateWidget(Context context, AppWidgetManager widgetManager, int widgetId) {
        RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget);

        // set list adapter
        Intent serviceIntent = new Intent(context, WidgetService.class);
        serviceIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, widgetId);
        serviceIntent.setData(Uri.parse(serviceIntent.toUri(Intent.URI_INTENT_SCHEME)));
        views.setRemoteAdapter(android.R.id.list, serviceIntent);
        views.setEmptyView(android.R.id.list, android.R.id.empty);

        // set widget title
        WidgetDataCategory category = new WidgetPreferences(context).getSavedCategory(widgetId);
        views.setTextViewText(R.id.titleText, context.getString(category.titleResourceId()));

        // set onclick listener - we create a pending intent template and when an items is clicked
        // the intent is filled with missing data and sent
        Intent startActivityIntent = new Intent(context, SimplePersonDetailActivity.class);
        startActivityIntent.setData(Uri.parse(startActivityIntent.toUri(Intent.URI_INTENT_SCHEME)));
        startActivityIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP);
        startActivityIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, widgetId);
        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, startActivityIntent, PendingIntent.FLAG_UPDATE_CURRENT);
        views.setPendingIntentTemplate(android.R.id.list, pendingIntent);

        // all hail to Google
        widgetManager.updateAppWidget(widgetId, views);
    }
}

FACTORY

public class WidgetFactory implements RemoteViewsService.RemoteViewsFactory {

    private Context context;
    private List<Person> people = new ArrayList<>();

    public WidgetFactory(Context context, Intent intent) {
        this.context = context;

        int widgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
        if (widgetId != AppWidgetManager.INVALID_APPWIDGET_ID) {
            WidgetPreferences prefs = new WidgetPreferences(context);

            WidgetDataCategory category = prefs.getSavedCategory(widgetId);
            int numberOfItemsToShow = prefs.getSavedLimit(widgetId);

            people = category.filterAndSlice(new PersonDao(context).getAllForGroup(Constants.SIMPLE_GROUP_ID), numberOfItemsToShow);
        }
    }

    @Override
    public void onCreate() {}

    @Override
    public void onDataSetChanged() {}

    @Override
    public void onDestroy() {}

    @Override
    public int getCount() {
        return people.size();
    }

    @Override
    public RemoteViews getViewAt(int position) {
        Person person = people.get(position);
        BigDecimal amount = ListViewUtil.sumTransactions(new TransactionDao(context).getAllForPerson(person));

        RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.item_widget);
        remoteViews.setTextViewText(R.id.nameText, person.getName());
        remoteViews.setTextViewText(R.id.amountText, MoneyFormatter.withoutPlusPrefix().format(amount));

        // fill details for the onclick listener (updating the pending intent template
        // set in the WidgetProvider)
        Intent listenerIntent = new Intent();
        listenerIntent.putExtra(Constants.PERSON_ID, people.get(position).getId());
        remoteViews.setOnClickFillInIntent(R.id.widgetItem, listenerIntent);

        return remoteViews;
    }

    @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;
    }
}

我会这样说notifyAppWidgetViewDataChanged方法应该适合你。

你必须建立AppWidgetManager并得到appWidgetIds然后打电话notifyAppWidgetViewDataChanged在你的AppWidgetManager.

伪代码，

AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
int appWidgetIds[] = appWidgetManager.getAppWidgetIds(
                           new ComponentName(context, WidgetProvider.class));
appWidgetManager.notifyAppWidgetViewDataChanged(appWidgetIds, R.id.listview);

更多内容可以查看我的回答here https://stackoverflow.com/a/12907825/726863其中包含 github 上的演示。