Fetching Shared Preferences String Value in Recyclerview Adapter

Question

I want to fetch String value from shared preferences and show it in Recylerview Adapter. Any help will be appreciated
This is my code

public  class MyViewHolder extends RecyclerView.ViewHolder {

   // private SharedPreferences prefs;

public Context context;

public ABCAdapter(List<ChatHistory>MessagesList,Context context) {

    this.MessageList = MessagesList;
    context=this.context;


}

    public MyViewHolder(View view) {
        super(view);


       // SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(context);
        //String profile_name = pref.getString("profile_name", null);

       prefs = context.getSharedPreferences(Constants.MY_PREFS_NAME, MODE_PRIVATE);
        String ipAdrs=prefs.getString("profile_name", "");
 }
}

profile_name is already stored in shared preferences.

here I am getting this error.

Attempt to invoke virtual method 'android.content.SharedPreferences android.content.Context.getSharedPreferences(java.lang.String, int)' on a null

Possible duplicate of [What is a NullPointerException, and how do I fix it?](https://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) — ADM, May 13 '19 at 10:58
how are you calling ABCAdapter? . You need to pass activity context — rafsanahmad007, May 13 '19 at 11:03

score 1 · Accepted Answer · answered May 13 '19 at 11:07

Here:

public ABCAdapter(List<ChatHistory>MessagesList,Context context) {

    this.MessageList = MessagesList;
    context=this.context;
}

should be:

public ABCAdapter(List<ChatHistory>MessagesList,Context context) {

    this.MessageList = MessagesList;
    this.context=context;   //this refers to class variable
}

Make sure to pass the activity context while creating the adapter.

score 1 · Answer 2 · answered May 13 '19 at 11:44

A much more easier(and better way) would be

itemView.getContext().getSharedPreferences(Constants.MY_PREFS_NAME, MODE_PRIVATE);
        String ipAdrs=prefs.getString("profile_name", "");

Also passing the Context to ViewHolder it is a very bad practice. You can get the Context whenever you need from any View

score 0 · Answer 3 · answered May 13 '19 at 10:59

0

you should pass SharedPreferences object to adapter Constructor and read data from it

answered May 13 '19 at 10:59

Poorya Taghizade

56
2
12

no you are passing the context you should create SharedPreferences in activity and pass SharedPreferences instance – Poorya Taghizade May 13 '19 at 11:11
@PooryaTaghizade why should he pass SharedPreferences when he can get the String he needs and pass it directly ? – MONK May 13 '19 at 11:46
@MONK because he need get data for each viewholder base item property.i guess – Poorya Taghizade May 13 '19 at 11:52
@PooryaTaghizade he's always getting the same string `prefs.getString("profile_name", "");` – MONK May 13 '19 at 12:02

Fetching Shared Preferences String Value in Recyclerview Adapter

3 Answers3