Flutter - remove a firebase document onTap() - firebase

Question

I have a ListView, filled with Firebase collection as chat messages.
When the user long press a ListTile (an item on the list), I show a BottomSheet.
When the user clicks the Delete button on the BottomSheet, the document should be removed. I'm unable to find a way to remove the selected document after tapping the "Delete" button.
The listview widget:
return ListView.builder(
padding: new EdgeInsets.all(8.0),
reverse: true,
itemCount: snapshot.data.documents.length,
itemBuilder: (_, int index) {
var message = snapshot.data.documents[index]["content"];
var from = snapshot.data.documents[index]["idFrom"];
return new ListTile(
leading: new CircleAvatar(
backgroundColor: Colors.blue,
child: new Image.network(
"http://res.cloudinary.com/kennyy/image/upload/v1531317427/avatar_z1rc6f.png")),
title: new Row(
children: <Widget>[
new Expanded(child: new Text(message))
]
),
subtitle: new Text(from),
onLongPress: () {
showModalBottomSheet<void>(context: context,
builder: (BuildContext context) {
return Container(
child: new Wrap(
children: <Widget>[
new ListTile(
leading: new Icon(Icons.delete),
title: new Text('Delete'),
onTap: () =>
// Remove the tapped document here - how?
print(snapshot.data.documents[index]["id"])
Firestore.instance.collection("chats").document("ROOM_1")
.collection("messages").document(snapshot.data.documents[index]["id"])
.delete();
)
)
]
)
);
});
}
);
});
I need to find a way to remove the document in the onTap() method. not sure why, but even when I do:
onTap: () => {
// Remove the tapped document here - how?
const id = snapshot.data.documents[index]["id"];
},
the IDE retruns an error Expected an identifier

Answer 1

To delete a document, we can use the runTransaction method of the Firestore.instance and use the delete method of the Transaction class.
await Firestore.instance.runTransaction((Transaction myTransaction) async {
await myTransaction.delete(snapshot.data.documents[index].reference);
});
instead of
Firestore.instance.collection("chats").document("ROOM_1")
.collection("messages").document(snapshot.data.documents[index]["id"])
.delete();
Here is the look of my dummy database before the deletion of doc1 document:
After deleting doc1:

Answer 2

If you know document id, You can delete easily.
Future<void> rejectJob(String jobId){
return _db.collection('jobs').document(jobId).delete();
}

Answer 3

Update 2021:
Add the following code to your button's onPressed method.
final collection = FirebaseFirestore.instance.collection('collection');
collection
.doc('some_id') // <-- Doc ID to be deleted.
.delete() // <-- Delete
.then((_) => print('Deleted'))
.catchError((error) => print('Delete failed: $error'));

Answer 4

.delete() method will only remove the document fields but will not remove the nested collections in the document.
Use runTransactions() method to delete the document completely without leaving any data behind.
FireBaseFirestore.instance.runTransactions((transaction) async =>
await transaction.delete(DocumentReference));
So, use runTransactions() instead of delete() method.

Answer 5

for simple and quick method try this (especially if you use login/signup)
Future deleteData(String id) async{
try {
await FirebaseFirestore.instance
.collection("users")
.doc(FirebaseAuth.instance.currentUser!.uid)
.collection("collection_name")
.doc(id)
.delete();
}catch (e){
return false;
}
}
then under the delete button you can pass the deleteData function
onPressed:() {
deleteData(collection_name.id);
Navigator.pop(context);
}, //delete