Eventbus

app/build.gradle

@@ -27,4 +27,6 @@ dependencies {
     compile 'com.android.support:appcompat-v7:25.3.0'
     compile 'com.android.support:design:25.3.0'
     testCompile 'junit:junit:4.12'
+
+    compile 'org.greenrobot:eventbus:3.0.0'
 }

app/src/main/java/edu/galileo/mvp/LoginActivity.java

@@ -2,33 +2,29 @@
 
 import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
-import android.os.AsyncTask;
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
-import android.text.TextUtils;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.widget.AutoCompleteTextView;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.Toast;
 
+import org.greenrobot.eventbus.EventBus;
+import org.greenrobot.eventbus.Subscribe;
+import org.greenrobot.eventbus.ThreadMode;
+
+import edu.galileo.mvp.event.CanceledEvent;
+import edu.galileo.mvp.event.PasswordErrorEvent;
+import edu.galileo.mvp.event.SuccessEvent;
+
 /**
  * A login screen that offers login via email/password.
  */
-public class LoginActivity extends AppCompatActivity {
+public class LoginActivity extends AppCompatActivity implements LoginView {
 
-    /**
-     * 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[] {
-        "test@galileo.edu", "testtest"
-    };
-    /**
-     * Keep track of the login task to ensure we can cancel it if requested.
-     */
-    private UserLoginTask mAuthTask = null;
+    private LoginPresenter loginPresenter;
 
     // UI references.
     private AutoCompleteTextView mEmailView;
@@ -56,6 +52,8 @@ public void onClick(View view) {
 
         mLoginFormView = findViewById(R.id.login_form);
         mProgressView = findViewById(R.id.login_progress);
+
+        loginPresenter = new LoginPresenterImpl(this);
     }
 
     /**
@@ -64,10 +62,6 @@ public void onClick(View view) {
      * 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);
@@ -76,53 +70,13 @@ private void attemptLogin() {
         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;
+        loginPresenter.validateCredentials(email, password);
     }
 
     /**
      * Shows the progress UI and hides the login form.
      */
+    @Override
     public void showProgress(final boolean show) {
         int shortAnimTime = getResources().getInteger(android.R.integer.config_shortAnimTime);
 
@@ -147,61 +101,45 @@ public void onAnimationEnd(Animator animation) {
         });
     }
 
-    /**
-     * 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.
+    @Override
+    public void setUsernameError(int messageResId) {
+        mEmailView.setError(getString(messageResId));
+        mEmailView.requestFocus();
+    }
 
-            try {
-                // Simulate network access.
-                Thread.sleep(2000);
-            } catch (InterruptedException e) {
-                return false;
-            }
+    @Override
+    public void setPasswordError(int messageResId) {
+        mPasswordView.setError(getString(messageResId));
+        mPasswordView.requestFocus();
+    }
 
-            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);
-                }
-            }
+    @Subscribe(threadMode = ThreadMode.MAIN)
+    public void onCanceledEvent(CanceledEvent canceledEvent) {
+        showProgress(false);
+    }
 
-            // TODO: register the new account here.
-            return true;
-        }
+    @Subscribe(threadMode = ThreadMode.MAIN)
+    public void onPasswordErrorEvent(PasswordErrorEvent passwordErrorEvent) {
+        showProgress(false);
+        setPasswordError(passwordErrorEvent.getMessageResId());
+    }
 
-        @Override
-        protected void onPostExecute(final Boolean success) {
-            mAuthTask = null;
-            showProgress(false);
+    @Subscribe(threadMode = ThreadMode.MAIN)
+    public void onSuccessEvent(SuccessEvent successEvent) {
+        showProgress(false);
+        Toast.makeText(LoginActivity.this, "Success", Toast.LENGTH_SHORT).show();
+    }
 
-            if (success) {
-                Toast.makeText(LoginActivity.this, "Success", Toast.LENGTH_SHORT).show();
-            } else {
-                mPasswordView.setError(getString(R.string.error_incorrect_password));
-                mPasswordView.requestFocus();
-            }
-        }
+    @Override
+    public void onStart() {
+        super.onStart();
+        EventBus.getDefault().register(this);
+    }
 
-        @Override
-        protected void onCancelled() {
-            mAuthTask = null;
-            showProgress(false);
-        }
+    @Override
+    public void onStop() {
+        super.onStop();
+        EventBus.getDefault().unregister(this);
     }
 }
 

app/src/main/java/edu/galileo/mvp/LoginModel.java

@@ -0,0 +1,6 @@
+package edu.galileo.mvp;
+
+public interface LoginModel {
+
+    void login(String username, String password);
+}

app/src/main/java/edu/galileo/mvp/LoginModelImpl.java

@@ -0,0 +1,73 @@
+package edu.galileo.mvp;
+
+import android.os.AsyncTask;
+
+import org.greenrobot.eventbus.EventBus;
+
+import edu.galileo.mvp.event.CanceledEvent;
+import edu.galileo.mvp.event.PasswordErrorEvent;
+import edu.galileo.mvp.event.SuccessEvent;
+
+public class LoginModelImpl implements LoginModel {
+
+    /**
+     * 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[] {
+        "test@galileo.edu:asdfasdf", "test2@galileo.edu:asdfasdf"
+    };
+
+    @Override
+    public void login(String username, String password) {
+        new UserLoginTask(username, password).execute((Void) null);
+    }
+
+    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 false;
+        }
+
+        @Override
+        protected void onPostExecute(final Boolean success) {
+            if (success) {
+                EventBus.getDefault().post(new SuccessEvent());
+            } else {
+                EventBus.getDefault().post(new PasswordErrorEvent(R.string.error_incorrect_password));
+            }
+        }
+
+        @Override
+        protected void onCancelled() {
+            EventBus.getDefault().post(new CanceledEvent());
+        }
+    }
+}

app/src/main/java/edu/galileo/mvp/LoginPresenter.java

@@ -0,0 +1,6 @@
+package edu.galileo.mvp;
+
+public interface LoginPresenter {
+
+    void validateCredentials(String username, String password);
+}

app/src/main/java/edu/galileo/mvp/LoginPresenterImpl.java

@@ -0,0 +1,45 @@
+package edu.galileo.mvp;
+
+import android.text.TextUtils;
+
+public class LoginPresenterImpl implements LoginPresenter {
+
+    private LoginView loginView;
+    private LoginModel loginModel;
+
+    public LoginPresenterImpl(LoginView loginView) {
+        this.loginView = loginView;
+        this.loginModel = new LoginModelImpl();
+    }
+
+    @Override
+    public void validateCredentials(String username, String password) {
+        // Check for a valid password, if the user entered one.
+        if (!TextUtils.isEmpty(password) && !isPasswordValid(password)) {
+            loginView.setPasswordError(R.string.error_invalid_password);
+            return;
+        }
+
+        // Check for a valid username.
+        if (TextUtils.isEmpty(username)) {
+            loginView.setUsernameError(R.string.error_field_required);
+            return;
+        } else if (!isEmailValid(username)) {
+            loginView.setUsernameError(R.string.error_invalid_email);
+            return;
+        }
+
+        loginView.showProgress(true);
+        loginModel.login(username, password);
+    }
+
+    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;
+    }
+}

app/src/main/java/edu/galileo/mvp/LoginView.java

@@ -0,0 +1,10 @@
+package edu.galileo.mvp;
+
+public interface LoginView {
+
+    void showProgress(boolean showProgress);
+
+    void setUsernameError(int messageResId);
+
+    void setPasswordError(int messageResId);
+}

app/src/main/java/edu/galileo/mvp/event/CanceledEvent.java

@@ -0,0 +1,4 @@
+package edu.galileo.mvp.event;
+
+public class CanceledEvent {
+}