CODEWITHSUNDEEP
fluttergoogle-cloud-firestorenulldart-null-safety
Ugocode
Ugocode

Reputation: 283

Please how do I set a String variable to null in firestore with flutter?

//I am trying to do this
String? userAvaterUrl = null;

//so I can do this:

FutureBuilder(
                          future: getPicture(),
                          builder: (context, snapshot) {
                            if (snapshot.hasData || snapshot.data != null) {
                              return CircleAvatar(
                                radius: width * 0.18,
                                backgroundImage:
                                    NetworkImage(snapshot.data.toString()),
                              );
                            } else {
                              return CircleAvatar(
                                  radius: width * 0.18,
                                  backgroundImage: AssetImage(
                                      "assets/images/icons2.png"));
                            }
                          },
                        ),

Upvotes: 0

Views: 208

Answers (1)

brightknight08
brightknight08

Reputation: 574

this line:

  if(snapshot.hasData || snapshot.data != null) {
    ...

would check if the document has data. if you need to get the userAvaterUrl from the doc, you will need to use:

  backgroundImage: NetworkImage(snapshot.data['userAvaterUrl'].toString()),

but remember that even if snapshot.hasData || snapshot.data != null, snapshot.data['userAvaterUrl'] can be null and you may want to make sure that your app can handle that. so, instead, you may want to do this:

  if(snapshot.hasData && 
      snapshot.data != null &&
      snapshot.data['userAvaterUrl'] != null && 
      snapshot.data['userAvaterUrl'] is String
  ) {
    ... // return avatar with the network image
  } else {
    ... // return avatar with the asset image
  }

by the way, if you are using flutter 2 with null-safety, this:

  String? userAvaterUrl = null;

would just be

  String? userAvaterUrl; // no need to set to null

Upvotes: 1

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