java - Difference between mContext.get().getApplicationContext() and getActivity()

Question

Why in my fragment getActivity() works but mContext.getApplicationContext() does not?

mDobPickerDialog = new DatePickerDialog(getActivity(), new OnDateSetListener() {

            public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
                Calendar newDate = Calendar.getInstance();
                newDate.set(year, monthOfYear, dayOfMonth);
                mDobEditText.setText(mDateFormatter.format(newDate.getTime()));
            }

        },newCalendar.get(Calendar.YEAR), newCalendar.get(Calendar.MONTH), newCalendar.get(Calendar.DAY_OF_MONTH));

My mContext is declared and initialized as:

private Context mContext;

public DisplayProfileFragment(Context context) {
        super();
        mContext = context;
    }

Answer 1

getActivity() returns the Activity the fragment is associated with.

http://developer.android.com/reference/android/app/Fragment.html#getActivity()

getApplicationContext() returns the global Application context.

http://developer.android.com/reference/android/content/Context.html#getApplicationContext()

As for why getApplicationContext() doesn't work in the code you have provided, because it shouldn't. You are creating a dialog on the current activity, for which you need the activity context, the application context should be used for functions like receivers, functions that should be destroyed when the application is destroyed, not when the activity is destroyed.