[Flutter/dart] Precautions when saving Map data in firestore
Overview
I use firebase's cloud firestore to store my app's data.
This time, I wanted to save the Map data in the firestore, but there were some precautions.
Note 1: key is String
It seems that the Map key that can be saved must be a String type. I wanted to save the Map data with int key, but I have no choice but to convert it to a String .
Note 2: Output from the forestore is not Map type
When retrieving data from the firestore, the type is _internalLinkedHashMap instead of Map type. If you try to assign this to a Map type variable, then exception
_InternalLinkedHashMap<dynamic, dynamic>' is not a subtype of type 'Map<String, dynamic>
occurs.
To assign to a Map type variable, do as follows.
Map<String, int> data= Map<String, int>.from(snapshot.data[key]);Recent Posts
See AllWhat want to do I want to create an input form using TextField. For example, if the input content is a monetary amount, I would like to display it in 3-digit delimiters with a ¥ prefix. Rather than ha
What want to do There is a variable that remain unchanged once the initial value is determined. However, it cannot be determined yet when the constructor is called. About such variable Define the vari
What want to do As the title suggests. Place two widgets in one line on the screen One in the center of the screen and the other on the right edge of the screen When I tried to do it with Row's mainAx
