LayoutInflator throws NullPointerException

Question

I'm new to android. And I'm trying to manipulate the TextView from aother class out of the GUI class which is the MainActivity class. But it throws an exception.

Following is the code i used...

Context ctx;
private SharedPreferences pref;

LayoutInflater inflater = LayoutInflater.from(ctx);
View myView = inflater.inflate(R.layout.activity_main, null);
TextView tv_datePick = (TextView) myView.findViewById(R.id.pickDate);
tv_datePick.setText(pref.getString(Constants.SELECTED_DATE,""));

I'm getting a date stored in SharedPreference and setting it to the TextView

Following is the Exception i get..

FATAL EXCEPTION: main
Process: srt.com.srtnew_nisal, PID: 25351
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference
  at android.view.LayoutInflater.from(LayoutInflater.java:219)
  at srt.com.srtnew_nisal.DatePickerFragment.onDateSet(DatePickerFragment.java:61)
  at android.app.DatePickerDialog.onClick(DatePickerDialog.java:134)
  at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:162)
  at android.os.Handler.dispatchMessage(Handler.java:102)
  at android.os.Looper.loop(Looper.java:135)
  at android.app.ActivityThread.main(ActivityThread.java:5290)
  at java.lang.reflect.Method.invoke(Native Method)
  at java.lang.reflect.Method.invoke(Method.java:372)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:911)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:706)

Following is the full code of the class that I'm using the LayoutInflator

public class DatePickerFragment extends DialogFragment implements DatePickerDialog.OnDateSetListener {

    Context ctx;
    private SharedPreferences pref;


    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        // Use the current date as the default date in the picker
        pref = this.getActivity().getSharedPreferences("Users",0);
        final Calendar c = Calendar.getInstance();
        int year = c.get(Calendar.YEAR);
        int month = c.get(Calendar.MONTH);
        int day = c.get(Calendar.DAY_OF_MONTH);

        // Create a new instance of DatePickerDialog and return it
        return new DatePickerDialog(getActivity(), this, year, month, day);
    }

    @Override
    public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {

        String new_month = "";

        if(Integer.parseInt(String.valueOf(month))<10) {
            new_month="0"+String.valueOf(month);
        }else{
            new_month = String.valueOf(month);
        }
        Log.d("month new",year+"-"+new_month+"-"+dayOfMonth);

        SharedPreferences.Editor editor = pref.edit();
        editor.putString(Constants.SELECTED_DATE,year+"-"+new_month+"-"+dayOfMonth);
        editor.apply();

        Log.d("shared pref",pref.getString(Constants.SELECTED_DATE,""));

        LayoutInflater inflater = LayoutInflater.from(this);
        View myView = inflater.inflate(R.layout.activity_main, null);
        TextView tv_datePick = (TextView) myView.findViewById(R.id.pickDate);
        tv_datePick.setText(pref.getString(Constants.SELECTED_DATE,""));


    }
}

What have i done wrong here? Am I doing the right way?

I have not initialized the ctx variable. I have declared it at the top. — Nisal Malinda Livera, Sep 15 '17 at 09:46
Change `LayoutInflater inflater = LayoutInflater.from(ctx);` to `LayoutInflater inflater = LayoutInflater.from(this);` — KeLiuyue, Sep 15 '17 at 09:46
@KeLiuyue it doesn't work here. It says `cannot be convert to Context` — Nisal Malinda Livera, Sep 15 '17 at 09:49
You need a constructor and pass `context` from `MainActivity` to it — M.Waqas Pervez, Sep 15 '17 at 09:49
use `LayoutInflater layoutInflater = LayoutInflater.from(getActivity());` .And try it. — KeLiuyue, Sep 15 '17 at 09:57
Also you can try `LayoutInflater inflater = getActivity().getLayoutInflater(); ` in your code @NisalMalindaLivera — KeLiuyue, Sep 15 '17 at 10:03
@KeLiuyue Both of them worked without any runtime erors. But i cant get the `TextView` updated. You have any idea about that issue? — Nisal Malinda Livera, Sep 15 '17 at 10:19
And you need to add `SharedPreferences sharedPreferences = getActivity().getApplicationContext().getSharedPreferences(SP_NAME, Context.MODE_PRIVATE);` in your code .And make sure that `pref.getString(Constants.SELECTED_DATE,"")` was not null .@NisalMalindaLivera — KeLiuyue, Sep 15 '17 at 10:29
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) — Vladyslav Matviienko, Sep 15 '17 at 11:24

score 0 · Answer 1 · answered Sep 15 '17 at 09:53

0

Here are several other ways you can get a reference to the LayoutInflater object:

LayoutInflater inflater = getLayoutInflater();

LayoutInflater inflater = ctx.getLayoutInflater();

LayoutInflater layoutInflater = (LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);

LayoutInflater layoutInflater = (LayoutInflater) ctx.getSystemService(LAYOUT_INFLATER_SERVICE);

Also, make sure that your Context ctx variable is not null. For this you should pass the Context from the constructor of the class.

answered Sep 15 '17 at 09:53

Sergey Emeliyanov

5,158
6
29
52

`LayoutInflater layoutInflater = (LayoutInflater) ctx.getSystemService(LAYOUT_INFLATER_SERVICE);` i tried this and it also threw the same exception – Nisal Malinda Livera Sep 15 '17 at 10:17
It seems that the problem is that your Context ctx is null. You should provide it a valid Context reference. Try passing the context from the constructor. – Sergey Emeliyanov Sep 15 '17 at 10:43

LayoutInflator throws NullPointerException

1 Answers1