Query nested Realm objects encapsulated in RealmList into RealmResults

问题

I have the following RealmObject:

public class City extends RealmObject {
    private String cityId;
    private RealmList<Street> streets;

    public String getId() {
        return cityId;
    }

    public void setCityId(String cityId) {
        this.cityId = cityId;
    }

    public RealmList<Street> getStreets() {
        return streets;
    }

    public void setStreets(RealmList<Street> streets) {
        this.streets = streets;
    }
}

Now having a cityId I need to query streets of particular city. How to do that? What I did try was:

    Realm.getInstance(context).where(City.class).equalTo("cityId", someCityId, false)
         .findFirst().getStreets().where().findAll()

But this leads into an Exception. I need to display streets in a ListView implementing filtering so I need streets to be RealmResults to use RealmBaseAdapter<Street>.

回答1:

The proper way would be to have an open Realm instance either opened in your Activity in onCreate() and closed in onDestroy(), or in your custom application class.

Then you can use this realm instance to query the realm

City city = realm.where(City.class).equalTo("cityId", cityId).findFirst();

Then you can access the RealmList<T> like any other list

RealmList<Street> streets = city.getStreets();

Then you can use a recyclerview to get the view for a given index within your streets list.

来源：https://stackoverflow.com/questions/31806848/query-nested-realm-objects-encapsulated-in-realmlist-into-realmresults