CODEWITHSUNDEEP
android
jamesxbrown
jamesxbrown

Reputation: 135

SharedPreferences shows null in Fragment (Android)

I am soo frustrated. In my very simple MainActivity I created a very simple Preference and everything works fine. I can display the value in other Activities, there are no errors or something. 

preference = getSharedPreferences("testPreference", Context.MODE_PRIVATE)

val editor = preference.edit()
editor.putString("nameOfUser", "TEST")
editor.apply()

Now I created a SettingsFragment and I want to display in this Fragment the value of the SharedPreferences - and it doesn't work. I tried like the example above, but it shows me the value null. I don't understand it why is it soooo difficult, when I'm using a Fragment?

Fragment:

var preference: SharedPreferences? = context?.getSharedPreferences("testPreference", 0)

override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
    setPreferencesFromResource(R.xml.preferences_profilesettings, rootKey)
    println(preference?.getString("nameOfUser", "error"))
}

Upvotes: 0

Views: 269

Answers (2)

AskNilesh
AskNilesh

Reputation: 69681

You are using a different Preferences name inside your SettingsFragment check

You need to Use testPreference Instead of nameOfUser

Use this 

preference = getSharedPreferences("testPreference", Context.MODE_PRIVATE)

Instead of 

preference = getSharedPreferences("nameOfUser", Context.MODE_PRIVATE)

UPDATE

lateinit preference: SharedPreferences

override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
preference = context?.getSharedPreferences("testPreference", 0)
    setPreferencesFromResource(R.xml.preferences_profilesettings, rootKey)
    println(preference?.getString("nameOfUser", "error"))
}

Upvotes: 2

guipivoto
guipivoto

Reputation: 18677

Problem is here:

var preference: SharedPreferences? = context?.getSharedPreferences("testPreference", 0)

When the Fragment is created, there's no Context associated with it yet. So, you can't use Context in the preference declaration.

Try something like:

var lateinit preference: SharedPreferences

override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
    preference = context?.getSharedPreferences("testPreference", 0)
    setPreferencesFromResource(R.xml.preferences_profilesettings, rootKey)
    println(preference?.getString("nameOfUser", "error"))
}

The same error does not happen with an Activity because an Activity is also a Context. Fragments on the other hand aren't Context. It receives a Context sometime later after its creation via onAttach(Context context)

Upvotes: 1

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