LoginActivity.java

package com.neoranga55.cleanguitestarchitecture;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.inputmethod.EditorInfo;
import android.widget.AutoCompleteTextView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import com.neoranga55.cleanguitestarchitecture.support.util.CountingIdlingResourceListener;

import java.util.Random;

/**
 * A login screen that offers login via email/password.
 */
public class LoginActivity extends AppCompatActivity {

    /**
     * Keep track of the login task to ensure we can cancel it if requested.
     */
    private UserLoginTask mAuthTask = null;

    // UI references.
    private AutoCompleteTextView mNameView;
    private EditText mPasswordView;
    private View mProgressView;
    private View mLoginFormView;
    private static CountingIdlingResourceListener sIdlingNotificationListener;

    public static void setIdlingNotificationListener(CountingIdlingResourceListener idlingNotificationListener) {
        sIdlingNotificationListener = idlingNotificationListener;
    }

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

        // Set up the login form.
        mNameView = (AutoCompleteTextView) findViewById(R.id.username);

        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;
            }
        });

        final Button emailSignInButton = (Button) findViewById(R.id.login_button);
        emailSignInButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                attemptLogin();
            }
        });
        // Shown the login button with a nice animation
        // only a 3 seconds after the application has started (app is idle in the meantime)
        emailSignInButton.setAlpha(0);
        emailSignInButton.setTranslationY(500);
        emailSignInButton.animate()
                .setStartDelay(1000)
                .setInterpolator(new AccelerateDecelerateInterpolator())
                .translationY(0)
                .alpha(1)
                .setDuration(2000)
                .setListener(new AnimatorListenerAdapter() {
                    @Override
                    public void onAnimationEnd(Animator animation) {
                        super.onAnimationEnd(animation);
                        if (sIdlingNotificationListener != null) {
                            sIdlingNotificationListener.decrement(); // Resource is idle again
                        }
                    }
                });
        if (sIdlingNotificationListener != null) {
            sIdlingNotificationListener.increment(); // Notify that our animation resource is busy
        }

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


    /**
     * 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;
        }
        // Show a progress spinner, while login
        showProgress(true);
        mAuthTask = new UserLoginTask(this, mNameView.getText().toString(),
                mPasswordView.getText().toString());
        mAuthTask.execute((Void) null);
    }

    /**
     * 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);
        }
    }

    /**
     * Represents an asynchronous login/registration task used to authenticate
     * the user.
     */
    public class UserLoginTask extends AsyncTask<Void, Void, Boolean> {

        private final Activity mActivity;
        private final String mUserName;
        private final String mPassword;

        UserLoginTask(Activity activity, String userName, String password) {
            mActivity = activity;
            mUserName = userName;
            mPassword = password;
        }

        @Override
        protected Boolean doInBackground(Void... params) {
            try { // Simulate network access with random delay between 1 and 5 seconds
                Thread.sleep((long)((new Random()).nextInt(4000) + 1000));
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return true;
        }

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

            Intent intent = new Intent(mActivity, WelcomeActivity.class);
            Bundle extras = new Bundle();
            extras.putString("USER", mUserName);
            intent.putExtras(extras);
            mActivity.startActivity(intent);
        }

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