AdminDialogFragment.java

package org.ohmage.fragments;

import org.ohmage.R;
import org.ohmage.triggers.utils.TrigTextInput;

import android.app.Activity;
import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.util.Base64;
import android.widget.Toast;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class AdminDialogFragment extends DialogFragment {

	public interface AdminCodeListener {
		public void onAdminCodeEntered(boolean success);
	}

	protected static final String ADMIN_CODE = "buZMBBBnFVSjOFZYlr3Dgt42H6U3dcfU73RsS08bSKY=\n";

	protected static final String SALT = "ohmage";

	private AdminCodeListener mListener;
	private boolean mSuccess = false;

	@Override
	public void onAttach(Activity activity) {
		super.onAttach(activity);
		try {
			mListener = (AdminCodeListener) activity;
		} catch (ClassCastException e) {
			throw new ClassCastException(activity.toString() + " must implement AdminCodeListener");
		}
	}

	@Override
	public void onDismiss(DialogInterface dialogInterface) {
		super.onDismiss(dialogInterface);
		mListener.onAdminCodeEntered(mSuccess);
	}

	@Override
	public Dialog onCreateDialog(Bundle savedInstanceState) {
		TrigTextInput ti = new TrigTextInput(getActivity());
		ti.setNumberMode(true);
		ti.setPasswordMode(true);
		ti.setAllowEmptyText(false);
		ti.setPositiveButtonText(getString(R.string.ok));
		ti.setNegativeButtonText(getString(R.string.cancel));
		ti.setTitle(getActivity().getString(R.string.admin_dialog_title));

		ti.setText("");

		ti.setOnClickListener(new TrigTextInput.onClickListener() {

			@Override
			public void onClick(TrigTextInput ti, int which) {
				if (which == TrigTextInput.BUTTON_POSITIVE) {
					try {
						MessageDigest digest = MessageDigest.getInstance("SHA-256");
						digest.reset();
						digest.update(SALT.getBytes());
						byte[] input = digest.digest(String.valueOf(ti.getText()).getBytes("UTF-8"));

						mSuccess = MessageDigest.isEqual(Base64.encode(input, 0), ADMIN_CODE.getBytes());
					} catch (NoSuchAlgorithmException e) {
						throw new RuntimeException(e);
					} catch (UnsupportedEncodingException e) {
						e.printStackTrace();
					}
					if(!mSuccess) {
						Toast.makeText(getActivity(), R.string.admin_dialog_invalid_pin, Toast.LENGTH_SHORT).show();
					}
				}
			}
		});

		return ti.createDialog();
	}
}