how can i store multiple data in sharedpreferences? - flutter

Question

I am getting user information like the username , profile pic and name .I want to store all that info inside Sharedpreferences so that i wont have to call firebase every time I need them.
here is how i am getting the data ,how can i store this data so that later on i can get user's name and its profilepic by checking it through its username ?
storeUsersInfo()async{
print('STORE CALLED');
QuerySnapshot querySnapshot = await DatabaseMethods().getUsers();
var length = querySnapshot.docs.length ;
print(length);
int i = 0 ;
while ( i < length ) {
print(name = "${querySnapshot.docs[i]["name"]}");
print(profilePicUrl = "${querySnapshot.docs[i]["profileURL"]}");
i++;
}
}
here is the firebase call
Future<QuerySnapshot> getUsers() async {
return await FirebaseFirestore.instance
.collection("users")
.get();
}
and if anyone needs anything else please ask .

Answer 1

You can store all the information in SharePreference by encoding picture objects to Base64String before storing them.
How you can encode it:
Future<String> encodeImageToBase64String(String imageUrl) async {
final response = await client.get(Uri.parse(imageUrl));
final base64 = base64Encode(response.bodyBytes);
return base64;
}
After Encoding the image, you can cache it to sharedPreference using
SharedPreferences pref = await SharedPreferences.getInstance();
//Save string to SharedPreference
pref.setString('image', encodedImageString);
How to Decode and use Image Later
//Get Encoded Image String from SharedPreferences
final base64String = pref.getString('image');
///Decodes Images file encoded to Base64String to Image
Uint8List decodeImageFromBase64String(String base64String) {
return base64Decode(base64String);
}
Finally, you can use this in your Image Widget like so
...
Image(image: MemoryImage(decodeImageFromBase64String))
Assuming you want to cache name, username and image gotten from firebase
//Create a model for the firebase data
class UserModel{
final String name;
final String username;
final String encodedImage;
UserModel(this.name, this.username, this.encodedImage);
String toJson(){
Map<String, dynamic> userMap = {
'name': name,
'username': username,
'image': encodedImage,
};
return json.encode(userMap);
}
}
//Encode the image HERE
encodeImageToBase64String(imageUrl);
//Pass in the parameters to the UserModel() constructor and Call //the toJson(), then Cache the Resulting String
String stringToCache = UserModel(nameString, usernameString, encodedImageString).toJson();

Answer 2

SharedPreferences takes a key and the data.
use this in an async funtion.
This syntax is sharedPreferences.setString(key, value)
So in a function,
SharedPreferences sharedPreferences = await SharedPreferences.getInstance();
sharedPreferences.setString("token", jsonResponse['access_token'].toString());
sharedPreferences.setString("userId", jsonResponse['customer_id'].toString());
You can get the stored data by sharedPreferences.getString(key).Like
var token = sharedPreferences.getString("token");

Answer 3

You can use a cache like https://pub.dev/packages/firestore_cache which does that for you.