Hi all - I’m trying to use SharedPreferences in my...

# android

[Will Nixon]

Hi all - I’m trying to use SharedPreferences in my app in order to save a few preferences that then need to update pretty instantaneously inside the app. I have a settings page, where the user can switch from light to dark mode, and also update the voice of a TTS functionality. When the user ‘saves changes’ - I call editor.putXXXX(key, value).apply() for each setting and then close out of the settings page. Unfortuntately, I neither see the settings changed in my main activity, nor see the updated settings when I go back into the settings page.

I understand that .apply() is asynchronous - I suspect that calling .apply() for each setting is going to cancel previous calls to .apply() - am I able to make several “puts” and then call .apply() just the once to make those several changes in one go? Why would I not see immediate changes in my main activity even if I call ‘sharedPrefs.getXXX’ again? I’m assuming it’s just an issue whereby the apply() function hasn’t actually finished yet?

I’ve tried Googling and SOing for solutions but not getting anywhere (edited)

[Will Nixon]

Would I only need 1 call to commit even if I make several .put calls?

[ritesh]

This might be of help, not sure how you have designed your use-case.
https://stackoverflow.com/questions/5960678/whats-the-difference-between-commit-and-apply-in-sharedpreferences

[Will Nixon]

Yeah I saw that - I think I need the immediacy of commit, unless there’s a nice way to handle an async call like apply so that I can wait until it’s applied before moving on?

[Ian Lake]

You absolutely don't need commit(). apply() is only about asynchronously writing to disk. The in memory shared preferences that it maintains is immediately updated

[Will Nixon]

Ok great, thanks @Ian Lake. I have a usecase whereby two putBooleans may get called one straight after the other. At the moment, it looks like it’s ignoring the second. Ie:

editor.putString('String', 'newVal')
editor.putBoolean("val 1", false)
editor.putBoolean("val 2", false)

editor.apply()

running this, the val 2 doesn’t change, the first two do

[Ian Lake]

Sounds like a good stack overflow question that shows your code where you write and read the shared preferences

[Will Nixon]

Turns out I was being an idiot, passing in the old value not the new one 🙄