how to Store app data and prevent data to get lost and also make app work at background in flutter - flutter

Question

I am a intermediate flutter developer and working on my first commercial app And I have almost created whole app ui but problem is when i close my app all data get lost . so how can i prevent it + how can i make my app work at background when app is close like in clock app . In clock app even if app is closed then also we get alarm at the timing we set . It is not possible to provide whole app code thats why i am explaining it in words . Hope you guys will understand the problem and provide best answer .

Answer 1

You can use internal data base concept to save user data like JWT key , user id, first name ,last name or app content for offline usage like blog articles ,pos system data for offline usage
Use Shared preferences to save basic data like user data, JWT but less secure
but if you need save complex data and need query or filter you can use hive and you can keep data more secure
And Alarm is totally deferent approach,
when we schedule alarm,alarm manager schedule task on system alarm services and wakeup app with intent and flutter Isolate class

Answer 2

We divide your question into two parts.
Question 01: How to store data locally :
You can use key-value storage like Shared preferences, Hive
If you are familiar with SQL you can use SQLite
If you are familiar with NoSQL you can use database like sembast
These are some of the popular databases that you can use with flutter. And much more available at pub.dev. But you want to use a database with your task. As an example simply store the user name or user id you can use Shared preferences
Question 02: Make Alarm Application :
For android applications, you can simply use android_alarm_manager
I suggest you take a deep look at the flutter docs about the subject:
Background processes
To run background processes continuously, take a look at this
package: https://pub.dev/packages/background_fetch
If you need to show scheduled messages, use local notifications:
I think by referring to these links you can get an idea.

Answer 3

To store data locally you can use local storage options like Database such as SQFlite, Hive etc or SharedPreference that will save your data locally and to run background process you need to use MethodChannel and write platform specific code or you also have the options to use Isolates. You may read more using this link
https://docs.flutter.dev/development/packages-and-plugins/background-processes