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Save string from firestore to variable

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2

I am trying to get a value from firestore and save it to a variable in flutter. I tried using StreamBuilder, but since i am not building a widget it does not work.

To clarify my problem, I am trying to get a url from a firestore document and then open it when i press a button in the app.

I also tried to adapt code i found in another question, but that returns null.

Future _getUrl() async
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 var data;
 docRef.get().then((datasnapshot)
 data = datasnapshot.data['url'];
 );
 return data;
 

The collection is called information, the document pdf, and the field url

dart flutter google-cloud-firestore

share|improve this question

asked Mar 28 at 18:18

Hannes HultergårdHannes Hultergård

4266 bronze badges

add a comment
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2

I am trying to get a value from firestore and save it to a variable in flutter. I tried using StreamBuilder, but since i am not building a widget it does not work.

To clarify my problem, I am trying to get a url from a firestore document and then open it when i press a button in the app.

I also tried to adapt code i found in another question, but that returns null.

Future _getUrl() async
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 var data;
 docRef.get().then((datasnapshot)
 data = datasnapshot.data['url'];
 );
 return data;
 

The collection is called information, the document pdf, and the field url

dart flutter google-cloud-firestore

share|improve this question

asked Mar 28 at 18:18

Hannes HultergårdHannes Hultergård

4266 bronze badges

add a comment
 | 

I am trying to get a value from firestore and save it to a variable in flutter. I tried using StreamBuilder, but since i am not building a widget it does not work.

To clarify my problem, I am trying to get a url from a firestore document and then open it when i press a button in the app.

I also tried to adapt code i found in another question, but that returns null.

Future _getUrl() async
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 var data;
 docRef.get().then((datasnapshot)
 data = datasnapshot.data['url'];
 );
 return data;
 

The collection is called information, the document pdf, and the field url

dart flutter google-cloud-firestore

share|improve this question

asked Mar 28 at 18:18

Hannes HultergårdHannes Hultergård

4266 bronze badges

Future _getUrl() async
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 var data;
 docRef.get().then((datasnapshot)
 data = datasnapshot.data['url'];
 );
 return data;
 

dart flutter google-cloud-firestore

dart flutter google-cloud-firestore

share|improve this question

asked Mar 28 at 18:18

Hannes HultergårdHannes Hultergård

4266 bronze badges

share|improve this question

asked Mar 28 at 18:18

Hannes HultergårdHannes Hultergård

4266 bronze badges

asked Mar 28 at 18:18

Hannes HultergårdHannes Hultergård

4266 bronze badges

asked Mar 28 at 18:18

Hannes HultergårdHannes Hultergård

4266 bronze badges

2 Answers
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1

This method will return null because you are not waiting for the get() future to return before you return data. docRef.get() is a Future, so it will execute asychronously. Meanwhile, your program will move on to the next line, which is return data.

Something like this would do what you want I think:

Future _getUrl() async
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 return docRef.get().then((datasnapshot)
 return datasnapshot.data['url'];
 );

share|improve this answer

answered Mar 28 at 19:12

KrisKris

52333 silver badges1010 bronze badges

add a comment
 | 

0

Since _getUrl is already marked as async you can also use await in its body to return the right value:

Future _getUrl() async 
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 await datasnapshot = docRef.get();
 let data = datasnapshot.data['url'];
 return data;

share|improve this answer

answered Mar 28 at 19:53

Frank van PuffelenFrank van Puffelen

277k3737 gold badges449449 silver badges469469 bronze badges

add a comment
 | 

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1

This method will return null because you are not waiting for the get() future to return before you return data. docRef.get() is a Future, so it will execute asychronously. Meanwhile, your program will move on to the next line, which is return data.

Something like this would do what you want I think:

Future _getUrl() async
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 return docRef.get().then((datasnapshot)
 return datasnapshot.data['url'];
 );

share|improve this answer

answered Mar 28 at 19:12

KrisKris

52333 silver badges1010 bronze badges

add a comment
 | 

1

This method will return null because you are not waiting for the get() future to return before you return data. docRef.get() is a Future, so it will execute asychronously. Meanwhile, your program will move on to the next line, which is return data.

Something like this would do what you want I think:

Future _getUrl() async
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 return docRef.get().then((datasnapshot)
 return datasnapshot.data['url'];
 );

share|improve this answer

answered Mar 28 at 19:12

KrisKris

52333 silver badges1010 bronze badges

add a comment
 | 

This method will return null because you are not waiting for the get() future to return before you return data. docRef.get() is a Future, so it will execute asychronously. Meanwhile, your program will move on to the next line, which is return data.

Something like this would do what you want I think:

Future _getUrl() async
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 return docRef.get().then((datasnapshot)
 return datasnapshot.data['url'];
 );

share|improve this answer

answered Mar 28 at 19:12

KrisKris

52333 silver badges1010 bronze badges

Future _getUrl() async
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 return docRef.get().then((datasnapshot)
 return datasnapshot.data['url'];
 );

share|improve this answer

answered Mar 28 at 19:12

KrisKris

52333 silver badges1010 bronze badges

answered Mar 28 at 19:12

KrisKris

52333 silver badges1010 bronze badges

answered Mar 28 at 19:12

KrisKris

52333 silver badges1010 bronze badges

0

Since _getUrl is already marked as async you can also use await in its body to return the right value:

Future _getUrl() async 
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 await datasnapshot = docRef.get();
 let data = datasnapshot.data['url'];
 return data;

share|improve this answer

answered Mar 28 at 19:53

Frank van PuffelenFrank van Puffelen

277k3737 gold badges449449 silver badges469469 bronze badges

add a comment
 | 

0

Since _getUrl is already marked as async you can also use await in its body to return the right value:

Future _getUrl() async 
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 await datasnapshot = docRef.get();
 let data = datasnapshot.data['url'];
 return data;

share|improve this answer

answered Mar 28 at 19:53

Frank van PuffelenFrank van Puffelen

277k3737 gold badges449449 silver badges469469 bronze badges

add a comment
 | 

Since _getUrl is already marked as async you can also use await in its body to return the right value:

Future _getUrl() async 
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 await datasnapshot = docRef.get();
 let data = datasnapshot.data['url'];
 return data;

share|improve this answer

answered Mar 28 at 19:53

Frank van PuffelenFrank van Puffelen

277k3737 gold badges449449 silver badges469469 bronze badges

Future _getUrl() async 
 DocumentReference docRef = Firestore.instance.collection('information').document('pdf');
 await datasnapshot = docRef.get();
 let data = datasnapshot.data['url'];
 return data;

share|improve this answer

answered Mar 28 at 19:53

Frank van PuffelenFrank van Puffelen

277k3737 gold badges449449 silver badges469469 bronze badges

answered Mar 28 at 19:53

Frank van PuffelenFrank van Puffelen

277k3737 gold badges449449 silver badges469469 bronze badges

answered Mar 28 at 19:53

Frank van PuffelenFrank van Puffelen

277k3737 gold badges449449 silver badges469469 bronze badges