android - Geofire - 未找到位置

Question

如何使用 Geo Queries 获取靠近传递的 GeoLocation(double lat, double lng) 的所有位置.我有以下代码(它什么也没发生):

public void setCurrentLatLng(double lat, double lng){
    this.lat = lat;
    this.lng = lng;
    GeoLocation geoLocation = new GeoLocation(lat, lng);
    updateCurrenLocation(geoLocation);
    GeoQuery geoQuery = geoFire.queryAtLocation(geoLocation, 8f);
    geoQuery.addGeoQueryDataEventListener(new GeoQueryDataEventListener() {

        @Override
        public void onDataEntered(DataSnapshot dataSnapshot, GeoLocation location) {
            Log.d("geoQuery","onDataEntered "+dataSnapshot.toString());
            // ...
        }

        @Override
        public void onDataExited(DataSnapshot dataSnapshot) {
            Log.d("geoQuery","onDataExited "+dataSnapshot.toString());
            // ...
        }

        @Override
        public void onDataMoved(DataSnapshot dataSnapshot, GeoLocation location) {
            Log.d("geoQuery","onDataMoved "+dataSnapshot.toString());
            // ...
        }

        @Override
        public void onDataChanged(DataSnapshot dataSnapshot, GeoLocation location) {
            Log.d("geoQuery","onDataChanged "+dataSnapshot.toString());
            // ...
        }

        @Override
        public void onGeoQueryReady() {
            // ...
            Log.d("geoQuery","onGeoQueryReady");
        }

        @Override
        public void onGeoQueryError(DatabaseError error) {
            Log.d("geoQuery","onGeoQueryError");
            // ...
        }

    });
    this.setChanged();
    notifyObservers();
    this.clearChanged();
    Log.d("update","clearChanged");
}

这是我的 firebase 数据:

如果需要，我想我愿意修改数据结构。

日志

09-12 08:55:33.818 17710-17710/es.rchampa.weirdo D/geoQuery: lat=40.4430883 lng=-3.721805
09-12 08:55:33.982 17710-17710/es.rchampa.weirdo D/geoQuery: lat=40.4430883 lng=-3.721805
09-12 08:55:33.986 17710-17710/es.rchampa.weirdo D/geoQuery: onGeoQueryReady
09-12 08:55:34.025 17710-17710/es.rchampa.weirdo D/geoQuery: onGeoQueryReady

Gradle 文件

....
// Firebase
implementation 'com.google.firebase:firebase-database:16.0.1'
implementation 'com.google.firebase:firebase-storage:16.0.1'
implementation 'com.google.firebase:firebase-auth:16.0.3'
implementation 'com.google.firebase:firebase-crash:16.2.0'
implementation 'com.google.firebase:firebase-core:16.0.3'

// Firebase UI
implementation 'com.firebaseui:firebase-ui-database:1.2.0'

//Firebase GeoFire
implementation 'com.firebase:geofire-android:2.3.1'

// Google Play Services
implementation 'com.google.android.gms:play-services-auth:16.0.0'
implementation 'com.google.android.gms:play-services-maps:15.0.1'
implementation 'com.google.android.gms:play-services-location:15.0.1'
....

更新

如果您愿意，我可以授予对我的私有(private)仓库的访问权限。

Answer 1

您将值 8f( float )作为 radius 传递给那里，而 radius 应该是 8.0d 或 Double.valueOf(8.0)，其中 MAX_SUPPORTED_RADIUS 等于 8587 公里。

虽然实际问题是，GeoFire 已经需要知道 .child("location")，但不可能用 引用;只有 DataSnapshot 有 getChildren()。

底线是:

you'd have to create a separate locations Reference, in order to avoid the nesting. nevertheless you still can use the related uid key for these nodes (or at least add it as a child-node), in order to be able to look up within the users Reference. it's a 1:1 relation, in between two References.

所以这是一个有效的 Java 示例，只是因为......

我们假设以下结构(如上所述):

{
  "locations" : {
    "CR88aa9gnDfJYYGq5ZTMwwC38C12" : {
      ".priority" : "9q8yywdgue",
      "g" : "9q8yywdgue",
      "l" : [ 37.7853889, -122.4056973 ]
    }
  },
  "users" : {
    "CR88aa9gnDfJYYGq5ZTMwwC38C12" : {
      "displayName" : "user 01",
      ...
    }
  }
}

数据库规则应该为 locations 字段 g 设置 .indexOn:

{
  "rules": {
    ...
    "locations": {
      ".indexOn": "g"
    }
  }
}

模块build.gradle中的依赖:

dependencies {
    ...
    implementation "com.firebase:geofire-android:2.3.1"
}

这演示了如何通过 GeoQuery 结果获取用户的快照；

注意 GeoQueryEventListener 而不是 GeoQueryDataEventListener:

public class GeofireActivity extends AppCompatActivity {

    private static final String LOG_TAG = GeofireActivity.class.getSimpleName();

    private DatabaseReference refBase     = null;
    private DatabaseReference refLocation = null;
    private DatabaseReference refUser     = null;

    private GeoFire geoFire = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.setContentView(R.layout.fragment_geofire);
        this.setReferences();
    }

    private void setReferences() {
        this.refBase = FirebaseDatabase.getInstance().getReference();
        this.refUser = refBase.child("users");
        this.refLocation = refBase.child("locations");
        this.geoFire = new GeoFire(this.refLocation);
    }

    private void searchNearby(double latitude, double longitude, double radius) {
        this.searchNearby(new GeoLocation(latitude, longitude), radius);
    }

    private void searchNearby(GeoLocation location, double radius) {

        GeoQuery geoQuery = this.geoFire.queryAtLocation(location, radius);
        geoQuery.addGeoQueryEventListener(new GeoQueryEventListener() {

            @Override
            public void onKeyEntered(String key, GeoLocation location) {

                String loc = String.valueOf(location.latitude) + ", " + String.valueOf(location.longitude);
                Log.d(LOG_TAG, "onKeyEntered: " + key + " @ " + loc);

                /* once the key is known, one can lookup the associated record */
                refUser.child(key).addListenerForSingleValueEvent(new ValueEventListener() {

                    @Override
                    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                        Log.d(LOG_TAG, "onDataChange: " + dataSnapshot.toString());
                    }

                    @Override
                    public void onCancelled(@NonNull DatabaseError firebaseError) {
                        Log.e(LOG_TAG, "onCancelled: " + firebaseError.getMessage());
                    }
                });
            }

            @Override
            public void onKeyExited(String key) {
                Log.d(LOG_TAG, "onKeyExited: " + key);
            }

            @Override
            public void onKeyMoved(String key, GeoLocation location) {
                Log.d(LOG_TAG, "onKeyMoved: " + key);
            }

            @Override
            public void onGeoQueryReady() {
                Log.d(LOG_TAG, "onGeoQueryReady");
            }

            @Override
            public void onGeoQueryError(DatabaseError error) {
                Log.e(LOG_TAG, "onGeoQueryError" + error.getMessage());
            }
        });
    }
}

为了保持完整性，需要在删除用户记录时删除关联的位置记录 - 否则会导致无法再查找 key 。