如何使用
Geo Queries获取接近传递的GeoLocation(double lat,double lng)的所有位置.
我有以下代码(它没有发生)：
我有以下代码(它没有发生)：
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,"onDataMoved "+dataSnapshot.toString());
// ...
}
@Override
public void onDataChanged(DataSnapshot dataSnapshot,"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");
}
这是我的火力基础数据：
我想我可以根据需要修改数据结构.
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' ....
UPDATE
如果您愿意,我可以授予访问我的私人仓库的权限.
解决方法
你将值8f(float)作为半径传递,而半径应该是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Reference来表示;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 relateduidkey for these nodes (or at least add it as a child-node),in order to be able to look up within the usersReference. it’s a1:1relation,in between twoReferences.
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",...
}
}
}
数据库规则应该有.indexOn用于位置字段g set：
{
"rules": {
...
"locations": {
".indexOn": "g"
}
}
}
模块的build.gradle中的依赖项：
dependencies {
...
api "com.firebase:geofire-android:2.3.1"
}
这表明了如何通过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,在删除用户记录时,需要删除关联的位置记录 – 否则会导致密钥无法再查找.