LoginActivity.java

package co.fppc.ig;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.annotation.TargetApi;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.LoaderManager.LoaderCallbacks;
import android.content.CursorLoader;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.Loader;
import android.database.Cursor;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.text.TextUtils;
import android.util.Log;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.inputmethod.EditorInfo;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.List;

import co.fppc.ig.database.model.User;
import co.fppc.ig.library.Constants;
import co.fppc.ig.library.GPSTracker;
import co.fppc.ig.library.Helper;
import co.fppc.ig.library.JSONParser;


/**
 * A login screen that offers login via email/password.
 */
public class LoginActivity extends Activity implements LoaderCallbacks<Cursor> {
    private User user;
    JSONParser jParser = new JSONParser();
    JSONObject json;
    /**
     * Keep track of the login task to ensure we can cancel it if requested.
     */

    // Mendeklarasikan instance/object dari UserLoginTask.
    // UserLoginTask adalah class untuk melakukan pengambilan data verifikasi login antara android dengan server
    // UserLoginTask didefinisikan didalam kelas ini sebagai inner class
    private UserLoginTask mAuthTask = null;

    // UI references.
    private AutoCompleteTextView mEmailView;
    private EditText mPasswordView;
    private View mProgressView;
    private View mLoginFormView;
    private GPSTracker gps;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        // Set up the login form.
        mEmailView = (AutoCompleteTextView) findViewById(R.id.email);
        populateAutoComplete();

        mPasswordView = (EditText) findViewById(R.id.password);
        mPasswordView.setOnEditorActionListener(new TextView.OnEditorActionListener() {
            @Override
            public boolean onEditorAction(TextView textView, int id, KeyEvent keyEvent) {
                if (id == R.id.login || id == EditorInfo.IME_NULL) {
                    attemptLogin();
                    return true;
                }
                return false;
            }
        });

        Button mEmailSignInButton = (Button) findViewById(R.id.sign_in_button);
        mEmailSignInButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                attemptLogin();
            }
        });

        Button buttonProfilAplikasi = (Button) findViewById(R.id.buttonProfilAplikasi);
        buttonProfilAplikasi.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                AlertDialog.Builder aboutDialog = new AlertDialog.Builder(LoginActivity.this);
                aboutDialog.setTitle("About App");
                // Get the layout inflater
                LayoutInflater inflater = getLayoutInflater();
                View view = inflater.inflate(R.layout.app_profile_dialog, null);
                // Inflate and set the layout for the dialog
                // Pass null as the parent view because its going in the dialog layout
                aboutDialog.setView(view)
                        // Add action buttons
                        .setNegativeButton(R.string.button_label_close, new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {

                            }
                        })
                ;
                aboutDialog.show();
            }
        });
        mLoginFormView = findViewById(R.id.login_form);
        mProgressView = findViewById(R.id.login_progress);

        // create class object
        gps = new GPSTracker(LoginActivity.this);
        // check if GPS enabled
        if (gps.canGetLocation()) {

            double latitude = gps.getLatitude();
            double longitude = gps.getLongitude();

            // \n is for new line
            //Helper.toast(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude);

            Log.d("_onLocationChanged_", "Lat: " + String.valueOf(String.format("%.8f", latitude)) + " Long: " + String.valueOf(String.format("%.8f", longitude)));
        } else {
            // can't get location
            // GPS or Network is not enabled
            // Ask user to enable GPS/network in settings
            gps.showSettingsAlert();
        }
    }

    private void populateAutoComplete() {
        getLoaderManager().initLoader(0, null, this);
    }


    // Fungsi yang digunakan untuk melakukan login dari aplikasi
    public void attemptLogin() {
        // Check apakah object mAuthTask belum terinstansiasi
        if (mAuthTask != null) {
            return;
        }

        // Reset errors.
        mEmailView.setError(null);
        mPasswordView.setError(null);

        // Store values at the time of the login attempt.
        String email = mEmailView.getText().toString();
        String password = mPasswordView.getText().toString();

        boolean cancel = false;
        View focusView = null;

        // Check apakah password tidak kosong dan password valid
        if (!TextUtils.isEmpty(password) && !isPasswordValid(password)) {
            mPasswordView.setError(getString(R.string.error_invalid_password));
            focusView = mPasswordView;
            cancel = true;
        }

        // Check untuk valid email dan formatnya.
        if (TextUtils.isEmpty(email)) {
            mEmailView.setError(getString(R.string.error_field_required));
            focusView = mEmailView;
            cancel = true;
        } else if (!isEmailValid(email)) {
            mEmailView.setError(getString(R.string.error_invalid_email));
            focusView = mEmailView;
            cancel = true;
        }

        // Jika cancel, maka tampilkan pesan error
        // Status cancel bernilai true jika syarat login pada form login tidak terpenuhi
        // Misalkan email / password kosong, dsb
        if (cancel) {
            // There was an error; don't attempt login and focus the first
            // form field with an error.
            focusView.requestFocus();
        } else {
            // Jika status cancel = false, atau tidak ada kesalahan, maka mulai melakukan verifikasi data login dengan server
            showProgress(true);
            mAuthTask = new UserLoginTask(email, password);
            mAuthTask.execute((Void) null);
        }
    }

    private boolean isEmailValid(String email) {
        //TODO: Replace this with your own logic
        return email.contains("@");
    }

    private boolean isPasswordValid(String password) {
        //TODO: Replace this with your own logic
        return password.length() > 2;
    }

    // Loader icon untuk login
    @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
    public void showProgress(final boolean show) {
        // On Honeycomb MR2 we have the ViewPropertyAnimator APIs, which allow
        // for very easy animations. If available, use these APIs to fade-in
        // the progress spinner.
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2) {
            int shortAnimTime = getResources().getInteger(android.R.integer.config_shortAnimTime);

            mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
            mLoginFormView.animate().setDuration(shortAnimTime).alpha(
                    show ? 0 : 1).setListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
                }
            });

            mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
            mProgressView.animate().setDuration(shortAnimTime).alpha(
                    show ? 1 : 0).setListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
                }
            });
        } else {
            // The ViewPropertyAnimator APIs are not available, so simply show
            // and hide the relevant UI components.
            mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
            mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
        }
    }

    @Override
    public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
        return new CursorLoader(this,
                // Retrieve data rows for the device user's 'profile' contact.
                Uri.withAppendedPath(ContactsContract.Profile.CONTENT_URI,
                        ContactsContract.Contacts.Data.CONTENT_DIRECTORY), ProfileQuery.PROJECTION,

                // Select only email addresses.
                ContactsContract.Contacts.Data.MIMETYPE +
                        " = ?", new String[]{ContactsContract.CommonDataKinds.Email
                .CONTENT_ITEM_TYPE},

                // Show primary email addresses first. Note that there won't be
                // a primary email address if the user hasn't specified one.
                ContactsContract.Contacts.Data.IS_PRIMARY + " DESC");
    }

    @Override
    public void onLoadFinished(Loader<Cursor> cursorLoader, Cursor cursor) {
        List<String> emails = new ArrayList<String>();
        cursor.moveToFirst();
        while (!cursor.isAfterLast()) {
            emails.add(cursor.getString(ProfileQuery.ADDRESS));
            cursor.moveToNext();
        }

        addEmailsToAutoComplete(emails);
    }

    @Override
    public void onLoaderReset(Loader<Cursor> cursorLoader) {

    }

    private interface ProfileQuery {
        String[] PROJECTION = {
                ContactsContract.CommonDataKinds.Email.ADDRESS,
                ContactsContract.CommonDataKinds.Email.IS_PRIMARY,
        };

        int ADDRESS = 0;
        int IS_PRIMARY = 1;
    }


    private void addEmailsToAutoComplete(List<String> emailAddressCollection) {
        //Create adapter to tell the AutoCompleteTextView what to show in its dropdown list.
        ArrayAdapter<String> adapter =
                new ArrayAdapter<String>(LoginActivity.this,
                        android.R.layout.simple_dropdown_item_1line, emailAddressCollection);

        mEmailView.setAdapter(adapter);
    }

    // Mendeklarasikan class UserLoginTask yang berfungsi untuk melakukan verifikasi data login dengan server
    public class UserLoginTask extends AsyncTask<Void, Void, Boolean> {

        private final String mEmail;
        private final String mPassword;

        UserLoginTask(String email, String password) {
            mEmail = email;
            mPassword = password;
        }

        @Override
        protected Boolean doInBackground(Void... params) {
            // TODO: attempt authentication against a network service.

            List<NameValuePair> par = new ArrayList<NameValuePair>();
            par.add(new BasicNameValuePair("email", mEmail));
            par.add(new BasicNameValuePair("password", mPassword));
            json = jParser.makeHttpRequest(Constants.MOBILE_API_SERVER_BASE_URL + "action_login.php", "POST", par);

            boolean valid = false;

            try {
                if (!json.getString("valid").equals("")) {
                    valid = true;
                    JSONObject jsonValid = json.getJSONObject("valid");
                    Log.d("_MSG_VALID_", json.getString("valid"));
                    user = new User(jsonValid.getInt("id"), jsonValid.getString("email"), jsonValid.getString("password"));
                }
            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return valid;
        }

        @Override
        protected void onPostExecute(final Boolean success) {
            mAuthTask = null;
            showProgress(false);

            // Melakukan pemeriksaan akun, jika sukses maka akan ditampilkan MainActivity
            // Passing data informasi dari user melalui intent 'USER_SESSION'
            if (success) {
                finish();
                Intent intent = new Intent(getApplicationContext(), MainActivity.class);
                intent.putExtra("USER_SESSION", user);
                startActivity(intent);
            } else {
                Helper.toast(getApplicationContext(), "Invalid login");
                mPasswordView.setError(getString(R.string.error_incorrect_password));
                mPasswordView.requestFocus();
            }
        }

        @Override
        protected void onCancelled() {
            mAuthTask = null;
            showProgress(false);
        }
    }
}