Question 78120 in Flutter Question posted in
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How can I access each document id in Firebase? – Flutter

In my blogapp ,I am trying to implement comment system in flutter using cloud firestore. Each document is a post and I am trying to add comments as a subcollection to each document. How can I access each document id so that I can access the subcollection ?

Here I tried to print the document id below but it shows error NoSuchMethodError: 'id' method not found Receiver: null Arguments: [] :

 final ref = await FirebaseFirestore.instance
                            .collection('blogs')
                            .add({
                              'title': titleController.text,
                              'body': myController.text,
                              'author': name,
                              'date': DateFormat('dd/MM/yyyy,hh:mm')
                                  .format(DateTime.now()),
                            })
                            .then((value) => successAlert(context))
                            .catchError((error) => 
                        errorAlert(context));
                        titleController.clear();
                        myController.clear();
                        print(ref.id);
                      }

This is my firestore database :

enter image description here

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2

Answers


  1. 0

    You need to have access to the document id inside blogs, and access it’s collection and the add your data like this…

    await FirebaseFirestore.instance
                            .collection('blogs')
                            .doc(documentId) // you need to enter this document id
                            .collection('comments').add({
                              'title': titleController.text,
                              'body': myController.text,
                              'author': name,
                              'date': DateFormat('dd/MM/yyyy,hh:mm')
                                  .format(DateTime.now()),
                            })
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  2. 0

    When you dont have the document id Firebase provides the get() command which returns the content of a collection. Like this:

    db.collection("cities").get().then((res) => print("Successfully completed"), onError: (e) => print("Error completing: $e"));

    But i realize that you will need the document id, so to get this you have to store the id after inserting a post, i’ve an example from a personal project:

    await firestore.collection('item').add({
      'quantity': element.quantity,
      'product_id': element.product.productId,
    }).then((value) {
      /// Here you can access [value.id] to get this document id.
      /// Now you can save it in a list or a class instance. Just keep it.
    })

    Now you can use the document id to update the post with a new comment, like this. For more information we have the Firestore documentation with flutter code snipets.

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