Continue from Tutorial 108

package com.notarazi.mylogin1;

import android.animation.Animator;

import android.animation.AnimatorListenerAdapter;

import android.annotation.TargetApi;

import android.content.pm.PackageManager;

import android.support.annotation.NonNull;

import android.support.design.widget.Snackbar;

import android.support.v7.app.AppCompatActivity;

import android.app.LoaderManager.LoaderCallbacks;

import android.content.CursorLoader;

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.view.KeyEvent;

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 android.widget.Toast;

import java.util.ArrayList;

import java.util.List;

import static android.Manifest.permission.READ_CONTACTS;

/**

* A login screen that offers login via email/password.

*/

public class LoginActivity extends AppCompatActivity implements LoaderCallbacks<Cursor> {

   /**

    * Id to identity READ_CONTACTS permission request.

    */

   private static final int REQUEST_READ_CONTACTS = 0;

   /**

    * A dummy authentication store containing known user names and passwords.

    * TODO: remove after connecting to a real authentication system.

    */

   private static final String[] DUMMY_CREDENTIALS = new String[]{

           "foo@example.com:hello", "bar@example.com:world"

   };

   /**

    * Keep track of the login task to ensure we can cancel it if requested.

    */

   private UserLoginTask mAuthTask = null;

   // UI references.

   private AutoCompleteTextView mEmailView;

   private EditText mPasswordView;

   private View mProgressView;

   private View mLoginFormView;

   @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.email_sign_in_button);

       mEmailSignInButton.setOnClickListener(new OnClickListener() {

           @Override

           public void onClick(View view) {

               attemptLogin();

           }

       });

       mLoginFormView = findViewById(R.id.login_form);

       mProgressView = findViewById(R.id.login_progress);

   }

   private void populateAutoComplete() {

       if (!mayRequestContacts()) {

           return;

       }

       getLoaderManager().initLoader(0, null, this);

   }

   private boolean mayRequestContacts() {

       if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {

           return true;

       }

       if (checkSelfPermission(READ_CONTACTS) == PackageManager.PERMISSION_GRANTED) {

           return true;

       }

       if (shouldShowRequestPermissionRationale(READ_CONTACTS)) {

           Snackbar.make(mEmailView, R.string.permission_rationale, Snackbar.LENGTH_INDEFINITE)

                   .setAction(android.R.string.ok, new View.OnClickListener() {

                       @Override

                       @TargetApi(Build.VERSION_CODES.M)

                       public void onClick(View v) {

                           requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS);

                       }

                   });

       } else {

           requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS);

       }

       return false;

   }

   /**

    * Callback received when a permissions request has been completed.

    */

   @Override

   public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,

                                          @NonNull int[] grantResults) {

       if (requestCode == REQUEST_READ_CONTACTS) {

           if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

               populateAutoComplete();

           }

       }

   }

   /**

    * Attempts to sign in or register the account specified by the login form.

    * If there are form errors (invalid email, missing fields, etc.), the

    * errors are presented and no actual login attempt is made.

    */

   private void attemptLogin() {

       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 for a valid password, if the user entered one.

       if (!TextUtils.isEmpty(password) && !isPasswordValid(password)) {

           mPasswordView.setError(getString(R.string.error_invalid_password));

           focusView = mPasswordView;

           cancel = true;

       }

       // Check for a valid email address.

       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;

       }

       if (cancel) {

           // There was an error; don't attempt login and focus the first

           // form field with an error.

           focusView.requestFocus();

       } else {

           // Show a progress spinner, and kick off a background task to

           // perform the user login attempt.

           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() > 4;

   }

   /**

    * Shows the progress UI and hides the login form.

    */

   @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)

   private 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<>();

       cursor.moveToFirst();

       while (!cursor.isAfterLast()) {

           emails.add(cursor.getString(ProfileQuery.ADDRESS));

           cursor.moveToNext();

       }

       addEmailsToAutoComplete(emails);

   }

   @Override

   public void onLoaderReset(Loader<Cursor> cursorLoader) {

   }

   private void addEmailsToAutoComplete(List<String> emailAddressCollection) {

       //Create adapter to tell the AutoCompleteTextView what to show in its dropdown list.

       ArrayAdapter<String> adapter =

               new ArrayAdapter<>(LoginActivity.this,

                       android.R.layout.simple_dropdown_item_1line, emailAddressCollection);

       mEmailView.setAdapter(adapter);

   }

   private interface ProfileQuery {

       String[] PROJECTION = {

               ContactsContract.CommonDataKinds.Email.ADDRESS,

               ContactsContract.CommonDataKinds.Email.IS_PRIMARY,

       };

       int ADDRESS = 0;

       int IS_PRIMARY = 1;

   }

   /**

    * Represents an asynchronous login/registration task used to authenticate

    * the user.

    */

   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.

           try {

               // Simulate network access.

               Thread.sleep(2000);

           } catch (InterruptedException e) {

               return false;

           }

           for (String credential : DUMMY_CREDENTIALS) {

               String[] pieces = credential.split(":");

               if (pieces[0].equals(mEmail)) {

                   // Account exists, return true if the password matches.

                   return pieces[1].equals(mPassword);

               }

           }

           // TODO: register the new account here.

           return true;

       }

       @Override

       protected void onPostExecute(final Boolean success) {

           mAuthTask = null;

           showProgress(false);

           if (success) {

               Toast.makeText(getApplicationContext(), "Success", Toast.LENGTH_LONG).show();

               //finish();

           } else {

               mPasswordView.setError(getString(R.string.error_incorrect_password));

               mPasswordView.requestFocus();

           }

       }

       @Override

       protected void onCancelled() {

           mAuthTask = null;

           showProgress(false);

       }

   }

}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

   xmlns:tools="http://schemas.android.com/tools"

   android:layout_width="match_parent"

   android:layout_height="match_parent"

   android:gravity="center_horizontal"

   android:orientation="vertical"

   android:paddingBottom="@dimen/activity_vertical_margin"

   android:paddingLeft="@dimen/activity_horizontal_margin"

   android:paddingRight="@dimen/activity_horizontal_margin"

   android:paddingTop="@dimen/activity_vertical_margin"

   tools:context="com.notarazi.mylogin1.LoginActivity">

   <!-- Login progress -->

   <ProgressBar

       android:id="@+id/login_progress"

       style="?android:attr/progressBarStyleLarge"

       android:layout_width="wrap_content"

       android:layout_height="wrap_content"

       android:layout_marginBottom="8dp"

       android:visibility="gone" />

   <ScrollView

       android:id="@+id/login_form"

       android:layout_width="match_parent"

       android:layout_height="match_parent">

       <LinearLayout

           android:id="@+id/email_login_form"

           android:layout_width="match_parent"

           android:layout_height="wrap_content"

           android:orientation="vertical">

           <android.support.design.widget.TextInputLayout

               android:layout_width="match_parent"

               android:layout_height="wrap_content">

               <AutoCompleteTextView

                   android:id="@+id/email"

                   android:layout_width="match_parent"

                   android:layout_height="wrap_content"

                   android:hint="@string/prompt_email"

                   android:inputType="textEmailAddress"

                   android:maxLines="1"

                   android:singleLine="true" />

           </android.support.design.widget.TextInputLayout>

           <android.support.design.widget.TextInputLayout

               android:layout_width="match_parent"

               android:layout_height="wrap_content">

               <EditText

                   android:id="@+id/password"

                   android:layout_width="match_parent"

                   android:layout_height="wrap_content"

                   android:hint="@string/prompt_password"

                   android:imeActionId="@+id/login"

                   android:imeActionLabel="@string/action_sign_in_short"

                   android:imeOptions="actionUnspecified"

                   android:inputType="textPassword"

                   android:maxLines="1"

                   android:singleLine="true" />

           </android.support.design.widget.TextInputLayout>

           <Button

               android:id="@+id/email_sign_in_button"

               style="?android:textAppearanceSmall"

               android:layout_width="match_parent"

               android:layout_height="wrap_content"

               android:layout_marginTop="16dp"

               android:text="@string/action_sign_in"

               android:textStyle="bold" />

       </LinearLayout>

   </ScrollView>

</LinearLayout>