How to get the number of Firestore documents in flutter

问题

I am building a flutter app and using Cloud Firestore. I want to get the number of all documents in the database.

I tried

Firestore.instance.collection('products').toString().length

but it didn't work.

回答1:

First, you have to get all the documents from that collection, then you can get the length of all the documents by document List. The below could should get the job done.

Firestore.instance.collection('products').getDocuments.then((myDocuments){
 print("${myDocuments.documents.length}");
});

回答2:

It Should Be - Firestore.instance.collection('products').snapshots().length.toString();

回答3:

Above suggestions will cause the client to download all of the documents in the collection to get the count. As a workaround, if your write operations are not frequently happening, you can put the length of the documents to firebase remote config and change it whenever you add/delete documents from the Firestore collection. Then you can fetch the length from firebase remote configs when you need it.

来源：https://stackoverflow.com/questions/53352632/how-to-get-the-number-of-firestore-documents-in-flutter