Android Open Source - WorkshopApp Login Activity

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License

The source code is released under:

This is free and unencumbered software released into the public domain. Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a co...

Java Source Code

package com.mikelane.workshopapp2;
// ww  w  .  j av  a  2 s  . co m
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.annotation.TargetApi;
import android.app.Activity;
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 java.util.ArrayList;
import java.util.List;


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

 */
public class LoginActivity extends Activity implements LoaderCallbacks<Cursor>{

    /**
     * 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() {
        getLoaderManager().initLoader(0, null, this);
    }


    /**
     * 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.
     */
    public 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)
    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);
    }

    /**
     * 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) {
                finish();
            } else {
                mPasswordView.setError(getString(R.string.error_incorrect_password));
                mPasswordView.requestFocus();
            }
        }

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

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