Handle login errors

app/src/main/java/it/danieleverducci/nextcloudmaps/activity/login/LoginActivity.java

@@ -25,6 +25,7 @@ import android.util.Log;
 import android.view.View;
 import android.widget.Button;
 import android.widget.ProgressBar;
+import android.widget.Toast;
 
 import androidx.annotation.NonNull;
 import androidx.appcompat.app.AppCompatActivity;
@@ -101,7 +102,8 @@ public class LoginActivity extends NextcloudMapsStyledActivity {
 
                     @Override
                     public void onError(Exception ex) {
-                        // TODO handle errors
+                        Toast.makeText(LoginActivity.this, R.string.login_error, Toast.LENGTH_SHORT).show();
+                        progress.setVisibility(View.GONE);
                     }
                 };
 
@@ -114,7 +116,7 @@ public class LoginActivity extends NextcloudMapsStyledActivity {
                 }
             });
         } catch (AccountImportCancelledException e) {
-            e.printStackTrace();
+            progress.setVisibility(View.GONE);
         }
     }