Shared Preferences in Flutter

Hi coders, Hope you are doing great..

In this article i am gonna teach you how to use shared preferences in flutter So first i am gonna tell which topics i am gonna cover in this article and if you interested to watch video in hindi the below is the the video 

In Hindi 👇

In English 👇

1. Save data in localStorage from user input
2. Read/Retrieve data from localStorage
3. Delete data from localStorage

And here i am gonna create a Text Field with 3 more Buttons which include Save, Read and Delete buttons and when user fill the text field and then click on add/save button then the data which filled in text field will be save into local storage and then if you wanna read which data is stored into local storage then you just need to click on Read button and at last but not the least if you wanna delete the data from local storage then just click in Delete button.

So let's get started to understand this deeply and at the end of the this post you will find the complete source code.

In main.dart file :-

we only call our main file where our whole code is written

home: LocalStorageData()

In Pubspec.yaml file:-

We add dependency of SharedPreferences:-

  shared_preferences: 2.0.8

In sharedp.dart file:-

TextEditingController controller = TextEditingController();

Create variable of type TextEditingController to use the data input by user into the text field.

late SharedPreferences prefs;

Declare variable of SharedPreferences named prefs which will be used to open SharedPreferences

String name = " ";

Creating String variable to show data from SharedPreferences to UI/Screen

we Created 3 buttons and 1 textfield and i assuming that you already know how to create them So In every Button when pressed i.e. onPressed function of Buttons we are going to call method which i am show why we have to create  them in deeply.

save() async {
  prefs = await SharedPreferences.getInstance();
  prefs.setString('text', controller.text.toString());
}

At above its called Save() function which is used to save the data(user input data from textfield) into SharedPreferences

using key: value format i.e. the data will be saved into the local by the name 'text' here using setString method and we

have to call getInstance method to get into SharedPreferences and here we used await because It maybe take some time

to get or save data in or from local so we want success and we can wait for some mili seconds to complete that part.

retrieve() async {
  prefs = await SharedPreferences.getInstance();
  setState(() {
    name = prefs.getString('text')!;
  });
}

Everything is same as save() function but with few little changes which are 

Here we are looking to read data so we used getString method and our data is saved
in key: value pair so i am calling key here 
and i am using setState so that the UI will be changed i.e. the data from shared
preferences will be shown in the screen and for that we have to use setState.
delete() async {
  prefs = await SharedPreferences.getInstance();
  prefs.remove('text');
  name = "";
  setState(() {});
}

Everything is same as above other 2 function but here i am going to delete data from SharedPreferences 
so just use remove() function and delete using key of that data.