问题
SharedPreferences are used to save Application data in Android.
commit() and apply() both are used to save the changes in the shared preferences.
As mentioned in Android Library:
public abstarct void apply():
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.
public abstract boolean commit ():
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.
Does this mean that the changes made by commit() are instant as compared with apply()? Which one is better?
If I need to use the same shared preference value in the next immediate activity, which one should I use? As I have seen if the value of Preference is updated it is not reflected till the application is restarted.
回答1:
Commit() is instantaneous but performs disk writes. If you are on the ui thread you should call apply() which is asynchronous.
回答2:
apply() - returns void
apply() was added in 2.3, it saves without returning a boolean indicating success or failure.
commit() - returns boolean value.
commit() returns true if the save works, false otherwise. apply() was added as the android dev team noticed that most no one took notice of the return value, so apply is faster.
You can refer to below link
What's the difference between commit() and apply() in Shared Preference
来源：https://stackoverflow.com/questions/15335456/difference-between-commit-and-apply-in-android-sharedpreferences