Retrieve users from Firestore within a range using GeoFireStore Android

问题

In my Android application, I need to get a list with users from Firestore within a range using GeoFireStore.

Database structure in Firestore:

All the information I got from this link.

Dependency:

implementation 'com.github.imperiumlabs:GeoFirestore-Android:v1.1.1'

Repositories:

maven { url 'https://jitpack.io' }

A code:

CollectionReference geoFirestoreRef = 
FirebaseFirestore.getInstance().collection("Users");
GeoFirestore geoFirestore = new GeoFirestore(geoFirestoreRef);

GeoQuery geoQuery = geoFirestore.queryAtLocation(new GeoPoint(32.848971, 35.0920935), 30);

geoQuery.addGeoQueryDataEventListener(new GeoQueryDataEventListener() {
    @Override
    public void onDocumentEntered(DocumentSnapshot documentSnapshot, GeoPoint location) {
    }

    @Override
    public void onDocumentExited(DocumentSnapshot documentSnapshot) {  
    }

    @Override
    public void onDocumentMoved(DocumentSnapshot documentSnapshot, GeoPoint location) { 
    }

    @Override
    public void onDocumentChanged(DocumentSnapshot documentSnapshot, GeoPoint location) {    
    }

    @Override
    public void onGeoQueryReady() {     
    }

    @Override
    public void onGeoQueryError(Exception exception) {
    }
});

So I didn't do I can't to call a function:

@Override
public void onDocumentEntered(DocumentSnapshot documentSnapshot, GeoPoint location) {
}

Only this function is called:

@Override
public void onGeoQueryReady() {     
}

回答1:

I'm adding this as an answer because I can't add comments.

So, what you're trying to do is getting all the DocumentSnapshots within a certain radius, for this your code is correct, you create a new GeoFirestore instance using a CollectionReference, and then you query the location you want.

The problem is that in your database currently there is no location data usable by GeoFirestore; you can solve this by appending the "location data" when you add your document to the database.

implementation 'com.github.imperiumlabs:GeoFirestore-Android:v1.2.0'
/*
 * You have to do this only one time for document
 * so the best is after the document upload to Firestore.
 */

//The id of the document you want to add the location
String documentId = documentReference.id;
GeoPoint point = new GeoPoint(/*lat,long of your point*/);
geoFirestore.setLocation(documentId, point);

You can find the official documentation here.

As the last tip, I suggest you update the library to the correct version (1.2.0) because the geo hashing algorithm is changed and you can take advantage of the kotlin capability.

回答2:

So, as Alex said, I missed GeoHash in my database. This is correct.

A code convert location to a hash:

GeoHash geoHash = new GeoHash(32.9235234, 35.3310622);
String res = geoHash.getGeoHashString();

result:

res = svc57cx33m

But for all this to work, you need to properly store data in Firestore.

How to store geo data correctly in Firestore here.

来源：https://stackoverflow.com/questions/56005186/retrieve-users-from-firestore-within-a-range-using-geofirestore-android

标签

java

android

firebase

google-cloud-firestore

geofirestore