Flutter async/await is not working between 2 Firebase functions - flutter

Question

I'm trying to call a cloud firestore function that has to persist an object only when another function returns the url of the file in Firebase Storage but the async await is not working and the second function is called anyway whereas the first function is not yet completed!!!
await schoolProfileProvider.uploadSchoolProfileAvatar(data).then( (data) {
schoolProfileProvider.addSchoolProfile(data);
});
print('PROFILE ADDED');
Future<SchoolProfileData> uploadSchoolProfileAvatar(SchoolProfileData data) async {
List<File> avatars = [];
data.childrenDetails.forEach((child) {
avatars.add(File(child.childImage));
});
try {
await _api.uploadFilesToStorage(avatars, 'image', 'png').then((urls) {
for (var i = 0; i < urls.length; i++) {
data.childrenDetails[i].childImage = urls[i];
print('ADD ' + data.childrenDetails[i].childImage);
}
});
} on Exception catch (e) {
print(e.toString());
}
return data;
}
T cast<T>(x) => x is T ? x : null;
Future<List<String>> uploadFilesToStorage(List<File> files, String type, String extension) async {
final urls = <Future<String>>[];
files.forEach((file) async {
StorageReference storageRef = storage.ref().child(file.path);
final StorageTaskSnapshot downloadUrl =
(await storageRef
.putFile(file, StorageMetadata(contentType: type + '/' + extension))
.onComplete);
await downloadUrl.ref.getDownloadURL().then((url) {
urls.add(cast<Future<String>>(url));
print('URL for file ${file.path} = ${url.toString()}');
});
});
print ('urls returned');
return Future.wait(urls);
}
Future addSchoolProfile(SchoolProfileData data) async{
var result;
try {
result = await _api.addDocument(data.toJson());
} on Exception catch(e) {
print (e.toString());
}
return result;
}

Answer 1

I've managed to make the things work and execute addSchoolProfile only after uploadFilesToStorage is completed by reducing the nested functions and making the await downloadUrl.ref.getDownloadURL() as the last instruction returned in the callee function.
Please find the code for who is interested in :
The caller :
schoolProfileProvider.addSchoolProfileAndUploadAvatar(data);
Future addSchoolProfileAndUploadAvatar(SchoolProfileData data) async {
List<File> avatars = [];
data.childrenDetails.forEach((child) {
avatars.add(File(child.childImage));
});
try {
for (int i=0;i<avatars.length;i++){
await _api.uploadFileToStorageAndGetUrl(avatars[i], 'image', 'png').then((url) {
print('URL for file ${avatars[i].path} = ${url.toString()}');
data.childrenDetails[i].childImage = url;
print('ADD ' + data.childrenDetails[i].childImage);
});
}
_api.addDocument(data.toJson()) ; // Add document in Google Firebase after setting the avatar url
} on Exception catch (e) {
print(e.toString());
}
}
The callee :
Future <String> uploadFileToStorageAndGetUrl(File file,String type, String extension) async{
StorageReference storageRef = storage.ref().child(file.path);
final StorageTaskSnapshot downloadUrl =
(await storageRef
.putFile(file, StorageMetadata(contentType: type + '/' + extension))
.onComplete);
return await downloadUrl.ref.getDownloadURL(); // return the url of the file in Google Storage
}