在onUpdate()方法中使用RemoteViewsFactory动态设置RemoteViews缓存和控件高度，并在onDataSetChanged()方法中更新缓存。具体的代码示例如下：

public class GlanceWidget extends AppWidgetProvider {

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

    for (int i = 0; i < appWidgetIds.length; i++) {
        int appWidgetId = appWidgetIds[i];

        RemoteViews views = new RemoteViews(context.getPackageName(),
                R.layout.widget_layout);

        Intent intent = new Intent(context, GlanceWidgetService.class);
        views.setRemoteAdapter(R.id.listView, intent);

        // Set the Empty view
        views.setEmptyView(R.id.listView, R.id.empty_view);

        // 设置RemoteViews高度
        int height = getListViewHeight(context);
        views.setListViewHeight(R.id.listView, height);

        // 更新Widget
        appWidgetManager.updateAppWidget(appWidgetId, views);
    }
    super.onUpdate(context, appWidgetManager, appWidgetIds);
}

private int getListViewHeight(Context context) {
    int rows = GlanceWidgetService.getRows();

    TypedValue tv = new TypedValue();
    int actionBarHeight = 0;

    if (context.getTheme().resolveAttribute(R.attr.actionBarSize, tv, true)) {
        actionBarHeight = TypedValue.complexToDimensionPixelSize(tv.data,
                context.getResources().getDisplayMetrics());
    }

    int height = rows * context.getResources().getDimensionPixelSize(R.dimen.widget_list_item_height)
            + actionBarHeight;

    return height;
}

}

public class GlanceWidgetService extends RemoteViewsService {

public GlanceWidgetService() {
    super();
}

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

public static int getRows() {
    return rows;
}

}

public class GlanceWidgetRemoteViewsFactory implements RemoteViewsService.RemoteViewsFactory {

private List mList = new ArrayList<>();
private Context mContext;

public GlanceWidgetRemoteViewsFactory(Context context, Intent intent) {
    mContext = context.getApplicationContext();
}

@Override
public void onCreate() {
    // 初始化缓存
    initData();
}

@Override
public void onDataSetChanged() {
    // 更新缓存
    initData();
}

@Override
public void onDestroy() {
    mList.clear();
}

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

@Override
public RemoteViews getViewAt(int position) {
    RemoteViews views = new RemoteViews(mContext.getPackageName(), R.layout.widget_list_item);
    views.setTextViewText(R.id.text, mList.get(position));
    return views;
}

@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;
}

private void initData() {
    mList.clear();
    for (int i = 0; i < 20; i++) {
        mList.add("Item " + i);
    }
}

}