Firebase Resources & Complex queries in Firestore using Dart & Flutter
1) Firebase integration in flutter:
https://medium.com/@themaaz32/firebase-integration-in-flutter-application-bb1c5f4a0eb9
2) Basics about cloud Firestore with Flutter:
https://medium.com/@atul.sharma_94062/how-to-use-cloud-firestore-with-flutter-e6f9e8821b27
3) Algolia search in Firestore using TextBox:
4) Write data in array of objects in Firestore:
Case-1(Overwrite a field inside of map in list):
Future<void> updateUserData(String bus_id, String speed, GeoPoint geoPoint) async {
Map<String, dynamic>data=new Map();
data[‘coordinate’]=geoPoint;
data[‘velocity’]=speed;var list=new List<Map<String, dynamic>>();
list.add(data);firestoreref.document(bus_id).setData({
‘locations’: FieldValue.arrayUnion(list)
});}
Case-2(Append the data in array):
Future<void> updateUserData(String bus_id, String speed, GeoPoint geoPoint) async {
Map<String, dynamic>data=new Map();
data[‘coordinate’]=geoPoint;
data[‘velocity’]=speed;var list=new List<Map<String, dynamic>>();
list.add(data);
firestoreref.document(bus_id).setData({
‘locations’: FieldValue.arrayUnion(list)
},merge:true);}
For using updateData() , you need to access a existing document ,otherwise you cant write the data.
Using setData() ,you can write both existing and non-existing document to write some data.
Merge:true ←- parameter is used for appending a existing data.
Read Data:
Fetch all the Array of objects of all documents:
Future<void> readLoacationData() async
{
var query = await Firestore.instance.collection(‘crowd_sourcing’).getDocuments();query.documents.forEach((doc) {
List<Map<dynamic, dynamic>> values = List.from(doc.data[‘locations’]);
});
}
Fetch array of objects of a single document:
Future<void> readLoacationData() async
{
var query = await Firestore.instance.collection(‘crowd_sourcing’).document(‘bus-1’);query.snapshots().forEach((doc) {
List<Map<dynamic, dynamic>> values = List.from(doc.data[‘locations’]);
});
Listener function in any Document Changes:
Structure-1
Future<void> readLoacationData() async
{
var query = await Firestore.instance.collection(‘crowd_sourcing’);query.snapshots().listen((querySnapshot) {
querySnapshot.documentChanges.forEach((change) {List<Map<dynamic, dynamic>>values=
List.from(change.document.data[‘locations’]);
});});
}
Structure-2
Future<void> readLoacationData() async
{
var query = await Firestore.instance.collection(‘bus_location’);query.snapshots().listen((querySnapshot) {
querySnapshot.documentChanges.forEach((change) {Map<dynamic, dynamic> values = Map.from(change.document.data);
});
});}
Whenever a value is updated in any of these documents,the listener function is called and the data of array of objects are updated in values list of map.(Structure-1).
Whenever a value is updated in any of these documents,the listener function is called and the data are updated in values of map. (Structure-2)
Listener function in single Document Changes:
Structure-1:
Future<void> readLoacationData() async
{
var query = await Firestore.instance.collection(‘crowd_sourcing’).document(‘bus-1’);List<Map<dynamic, dynamic>> main_list=new List<Map<dynamic, dynamic>>();
query.snapshots().listen((querySnapshot) {
List<Map<dynamic, dynamic>> values = List.from(querySnapshot.data[‘locations’]);
});
