How to change values in the shared preference

Question

I've created an application which uses a shared preference in order for the user to login. The password of the user is saved in the preference. My problem is, how can I change the password in the preference if the user wants to change his/her password?

Answer 1

SharedPreferences prefs = ... // you already know how to use prefs and have one of this objects
Editor editor = prefs.edit();
editor.putString("password", "new value");
editor.apply();

Answer 2

Use apply() instead of commit()

It is recommended that you use Editor.apply() instead of commit() because apply() works asynchronously in the background therefore it is less likely that there will be ANR because of that(if at all).

getSharedPreferences("FILE_NAME", 0 /*FILE_MODE*/)
     .edit()
     .putString("password", "new value")
     .apply();

Docs mention about apply() ,

Commit your preferences changes back from this Editor to the SharedPreferences object it is editing. This atomically performs the requested modifications, replacing whatever is currently in the SharedPreferences.

Note that when two editors are modifying preferences at the same time, the last one to call apply wins.

Unlike commit(), which writes its preferences out to persistent storage synchronously, apply() commits its changes to the in-memory SharedPreferences immediately but starts an asynchronous commit to disk and you won't be notified of any failures. If another editor on this SharedPreferences does a regular commit() while a apply() is still outstanding, the commit() will block until all async commits are completed as well as the commit itself.

As SharedPreferences instances are singletons within a process, it's safe to replace any instance of commit() with apply() if you were already ignoring the return value.

You don't need to worry about Android component lifecycles and their interaction with apply() writing to disk. The framework makes sure in-flight disk writes from apply() complete before switching states.