SingleChoiceDialogFragment.java

import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatDialogFragment;
import android.util.Log;

/**
 * Created by Giang Nguyen on 6/25/16.
 */
public class SingleChoiceDialogFragment extends AppCompatDialogFragment {

  public static final String EXTRA_TITLE = "title";
  public static final String EXTRA_ITEMS = "items";
  public static final String EXTRA_SELECTION = "selection";
  private static final String TAG = "SingleChoiceDialog";

  public static SingleChoiceDialogFragment newInstance(String title, String[] items, int selection) {
    if (title == null || items == null || items.length == 0) {
      throw new NullPointerException("title and items must not be null or empty");
    }
    if (selection < 0 || selection > items.length - 1) {
      throw new IllegalArgumentException("selection must be in [0, item.length)");
    }
    Bundle args = new Bundle();
    args.putString(EXTRA_TITLE, title);
    args.putStringArray(EXTRA_ITEMS, items);
    args.putInt(EXTRA_SELECTION, selection);

    SingleChoiceDialogFragment fragment = new SingleChoiceDialogFragment();
    fragment.setArguments(args);
    return fragment;
  }

  @NonNull @Override public Dialog onCreateDialog(Bundle savedInstanceState) {
    final Bundle args = getArguments();
    final String title;
    final String[] items;
    final int selection;
    if (args != null) {
      title = args.getString(EXTRA_TITLE);
      items = args.getStringArray(EXTRA_ITEMS);
      selection = args.getInt(EXTRA_SELECTION);
    } else {
      title = "";
      items = new String[0];
      selection = 0;
    }
    return new AlertDialog.Builder(getContext())
        .setTitle(title)
        .setSingleChoiceItems(items, selection, new DialogInterface.OnClickListener() {
          @Override public void onClick(DialogInterface dialog, int which) {
            dialog.dismiss();
            onItemSelected(which);
          }
        })
        .create();
  }

  private void onItemSelected(int which) {
    if (getParentFragment() instanceof OnItemSelectedListener) {
      ((OnItemSelectedListener) getParentFragment()).onItemSelected(which);
    } else if (getActivity() instanceof OnItemSelectedListener) {
      ((OnItemSelectedListener) getActivity()).onItemSelected(which);
    } else {
      Log.i(TAG, "onItemSelected() called with: " + "which = [" + which + "]");
    }
  }

  public interface OnItemSelectedListener {
    void onItemSelected(int position);
  }
}