保存实例活动状态以维持用户登录？

Question

I am developing an Android application that has a log in form and should maintain the user logged in. Basically what I have to do is make a request to an API and send the user email and password, that request returns a JSONObject which I manage just fine.

I have a cookieStore instance and save them into the user preferences through an instance of SharedPreferences , so every time I need the current user credentials I just get them from the preferences.

Thing is, if I close the app on my phone (I think that means to "pause" it, right?) I lost all my data which actually makes sense because I'm never saving the instance state of my activities.

My question is:

What do I need to save into the instance state of my activities in order to maintain the user logged in? I could save the preferences? How do I do it? And also, is that suppose to be done on the onResume() method of each activity?

Hope someone can help me with this, I'm just starting to develop in Android. :)

Thanks in advance.

Answer 1

data saved in SharedPreferences doesn't get lost when you close/destroy your app. just check for login details OnResume in the SharedPreferences. Don't forget to delete it from SharedPreferences when the user log out.

you could also save datetime of login in SharedPreferences and check it OnResume to see if user is timeout or not.

Answer 2

If you are using SharedPreferences and you don't want/need to save the current state of your activity you could simply get the values from SharedPreferences(if any) in onResume() method.

If you wan't to preserve the state of your activity, you must use the onSaveInstanceState(Bundle outState) method to save your data in the Bundle and in onCreate(Bundle savedInstanceState) to get the data from the Bundle and populate your View's.