How to call NumberPicker's onvaluechange from SharedPreferences?

Question

I want to update the NumberPicker using the value stored in Shared Preferences. This is all happening inside a fragment, there is also a button which calls the onValueChange() method whenever the user clicks on it.

HomeFragment.java

import android.content.SharedPreferences;
import android.widget.NumberPicker;


public class HomeFragment extends Fragment {

NumberPicker numberPicker;
SharedPreferences sharedPref;

public HomeFragment() {
    // Required empty public constructor
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View rootView = inflater.inflate(R.layout.fragment_home, container, false);

    numberPicker = (NumberPicker) rootView.findViewById(R.id.np);

    //Populate NumberPicker values from minimum and maximum value range
    //Set the minimum value of NumberPicker
    numberPicker.setMinValue(0);
    //Specify the maximum value/number of NumberPicker
    numberPicker.setMaxValue(239);

    //Gets whether the selector wheel wraps when reaching the min/max value.
    numberPicker.setWrapSelectorWheel(true);

    //Set a value change listener for NumberPicker
    final NumberPicker.OnValueChangeListener np_listener = new NumberPicker.OnValueChangeListener() {
        @Override
        public void onValueChange(NumberPicker picker, int oldVal, int newVal){

            //Statement goes here...

            SharedPreferences.Editor editor = sharedPref.edit();
            editor.putInt("someInteger", newVal);
            editor.commit();
        }
    };

    numberPicker.setOnValueChangedListener(np_listener);

    b1 = (Button) rootView.findViewById(R.id.button);
    b1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            int oldValue = numberPicker.getValue();
            numberPicker.setValue(oldValue + 1);
            np_listener.onValueChange(numberPicker, oldValue, oldValue + 1);
        }
    });


    // Inflate the layout for this fragment
    return rootView;
}
}

Whenever the NumberPicker value changes, I'm saving it in Preferences but where to retrieve the value? I know the code to retrieve:

SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
int someInteger = sharedPref.getInt("someInteger", 0);

But where to put this code, inside onCreate() or onCreateView()? After the value is retrieved if it exists then how to call onValueChange() so that all the statements inside that method gets executed?

Answer 1

You don't have to call it from SharedPreferences.

Inside onCreateView, set the NumberPicker value using the setValue method.

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // ... some code ...

    SharedPreferences sharedPref = getActivity().getPreferences(Context.MODE_PRIVATE);
    // Use default value 0 if key does not exist
    int someInteger = sharedPref.getInt("someInteger", 0);

    numberPicker = (NumberPicker) rootView.findViewById(R.id.np);
    numberPicker.setValue(someInteger);

    // ...

}