在RemoteViewsService中注册DataSetObserver并手动调用onDataSetChanged()方法。

代码示例：

1. 在RemoteViewsService中注册DataSetObserver

public class MyWidgetRemoteViewsService extends RemoteViewsService {

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

}

public class MyWidgetRemoteViewsFactory implements RemoteViewsService.RemoteViewsFactory {

    private Context mContext;
    private List mDataList;

    private DataSetObserver mDataSetObserver = new DataSetObserver() {
        @Override
        public void onChanged() {
            super.onChanged();
            // 数据集发生变化时，手动调用onDataSetChanged()方法
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
                MyWidgetRemoteViewsService.this.onDataSetChanged();
            }
        }
    };

    public MyWidgetRemoteViewsFactory(Context context, Intent intent) {
        mContext = context;
        mDataList = new ArrayList<>();
        // 注册DataSetObserver
        mDataList.registerDataSetObserver(mDataSetObserver);
    }

    // ... 省略其他方法 ...

}

2. 更新RemoteViews时，调用notifyAppWidgetViewDataChanged()方法

public class MyWidgetProvider extends AppWidgetProvider {

    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        super.onUpdate(context, appWidgetManager, appWidgetIds);

        for (int appWidgetId : appWidgetIds) {
            RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget_layout);
            // 设置ListView的adapter
            remoteViews.setRemoteAdapter(R.id.list_view, new Intent(context, MyWidgetRemoteViewsService.class));
            // 更新ListView的内容
            appWidgetManager.notifyAppWidgetViewDataChanged(appWidgetId, R.id.list_view);
            // 更新widget视图
            appWidgetManager.updateAppWidget(appWidgetId, remoteViews);
        }
    }

}