Remove AsyncTask from login, add proper messages

app/src/main/java/com/testapp/LoginActivity.java

@@ -27,8 +27,6 @@ import retrofit2.Response;
 
 public class LoginActivity extends AppCompatActivity {
 
-    private UserLoginTask mAuthTask = null;
-
     private AutoCompleteTextView mUsernameView;
     private EditText mPasswordView;
     private View mProgressView;
@@ -92,10 +90,6 @@ public class LoginActivity extends AppCompatActivity {
     }
 
     private void attemptLogin() {
-        if (mAuthTask != null) {
-            return;
-        }
-
         mUsernameView.setError(null);
         mPasswordView.setError(null);
 
@@ -121,14 +115,34 @@ public class LoginActivity extends AppCompatActivity {
             focusView.requestFocus();
         } else {
             showProgress(true);
-            mAuthTask = new UserLoginTask(username, password);
-            mAuthTask.execute((Void) null);
 
-            Intent intent = new Intent(this, NavDrawerActivity.class);
+            AppUtils.username = username;
+            AppUtils.password = password;
+            Call<Token> call = AppUtils.service.getToken();
+            call.enqueue(new Callback<Token>() {
+                @Override
+                public void onResponse(Call<Token> call, Response<Token> response) {
+                    showProgress(false);
+                    if(response.code() == 401) {
+                        mUsernameView.setError("");
+                        mPasswordView.setError("");
+                        Toast.makeText(LoginActivity.this, "Invalid credentials!", Toast.LENGTH_LONG).show();
+                    } else {
+                        Toast.makeText(LoginActivity.this, "Logged in as " + AppUtils.username + " successfully.", Toast.LENGTH_LONG).show();
+                        Intent intent = new Intent(LoginActivity.this, NavDrawerActivity.class);
                         startActivity(intent);
                     }
                 }
 
+                @Override
+                public void onFailure(Call<Token> call, Throwable t) {
+                    showProgress(false);
+                    Toast.makeText(LoginActivity.this, "Server failure, please try again. Message: " + t.getMessage(), Toast.LENGTH_LONG);
+                }
+            });
+        }
+    }
+
     @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
     private void showProgress(final boolean show) {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2) {
@@ -156,50 +170,4 @@ public class LoginActivity extends AppCompatActivity {
             mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
         }
     }
-
-    public class UserLoginTask extends AsyncTask<Void, Void, Boolean> {
-
-        private final String mUsername;
-        private final String mPassword;
-
-        UserLoginTask(String username, String password) {
-            mUsername = username;
-            mPassword = password;
-        }
-
-        @Override
-        protected Boolean doInBackground(Void... params) {
-            AppUtils.username = mUsername;
-            AppUtils.password = mPassword;
-            Call<Token> call = AppUtils.service.getToken();
-            call.enqueue(new Callback<Token>() {
-                @Override
-                public void onResponse(Call<Token> call, Response<Token> response) {
-                    Toast.makeText(LoginActivity.this, response.body().getToken(), Toast.LENGTH_LONG).show();
-                }
-
-                @Override
-                public void onFailure(Call<Token> call, Throwable t) {
-
-                }
-            });
-            return true;
-        }
-
-        @Override
-        protected void onPostExecute(final Boolean success) {
-            mAuthTask = null;
-            showProgress(false);
-
-            if (success) {
-                finish();
-            }
-        }
-
-        @Override
-        protected void onCancelled() {
-            mAuthTask = null;
-            showProgress(false);
-        }
-    }
 }