java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()'

Question

I have a class dedicated to managing sharedpreferences, however I keep getting a NPE on one of my calls. Heres the class,

public class UserManager extends Activity{

Context mContext;

UserManager(Context mContext){
    this.mContext = mContext;
}


public boolean getFromMatches(String userUid, String matchUid){
    SharedPreferences spMatches = mContext.getSharedPreferences(getString(R.string.match_key), Context.MODE_PRIVATE);
    if(spMatches.contains(userUid + matchUid)){
        return true;
    }else{
        return false;
    }
}

}

This is what is passed from my main activity:

    @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_screen);

    userManager = new UserManager(getApplicationContext());
}

The NPE is received at this line:

SharedPreferences spMatches = mContext.getSharedPreferences(getString(R.string.match_key), Context.MODE_PRIVATE);

@SpecialSnowflake Use this.mContext instead of mcontext in the line `mContext.getSharedPreferences(getString(R.string.match_key), Context.MODE_PRIVATE);` — Debojyoti, Aug 03 '16 at 09:03

score 0 · Answer 1 · answered Aug 03 '16 at 09:00

0

Use this

SharedPreferences spMatches = mContext.getSharedPreferences(getResources().getString(R.string.match_key), Context.MODE_PRIVATE);

answered Aug 03 '16 at 09:00

Vivek Mishra

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score 0 · Accepted Answer · answered Aug 03 '16 at 09:01

replace the getFromMatches function with this

public boolean getFromMatches(String userUid, String matchUid){
     SharedPreferences spMatches =  mContext.getSharedPreferences(mContext.getString(R.string.match_key), Context.MODE_PRIVATE);
     if(spMatches.contains(userUid + matchUid)){
        return true;
     }else{
       return false;
     }
}

for calling getString or any resources you will need Context

java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()'

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