move error_matrixid label below matrixid input, made hide/show for the label, made red underline for invalid input, add to TextField class isValid() setValid() for custom validation

src/LoginPage.cpp

@@ -137,11 +137,13 @@ LoginPage::LoginPage(QWidget *parent)
         serverLayout_ = new QHBoxLayout();
         serverLayout_->addWidget(serverInput_, 0, Qt::AlignVCenter);
 
-        form_layout_->addLayout(matrixid_error_layout_);
         form_layout_->addLayout(matrixidLayout_);
+        form_layout_->addLayout(matrixid_error_layout_);
         form_layout_->addWidget(password_input_);
         form_layout_->addWidget(deviceName_, Qt::AlignHCenter);
         form_layout_->addLayout(serverLayout_);
+    
+        error_matrixid_label_->hide(); 
 
         button_layout_ = new QHBoxLayout();
         button_layout_->setSpacing(0);
@@ -194,7 +196,9 @@ LoginPage::loginError(const QString &msg)
 void
 LoginPage::matrixIdError(const QString &msg)
 {
+        error_matrixid_label_->show();
         error_matrixid_label_->setText(msg);
+        matrixid_input_->setValid(false);
 }
 
 bool
@@ -218,6 +222,8 @@ LoginPage::onMatrixIdEntered()
                 return;
         } else {
                 error_matrixid_label_->setText("");
+                error_matrixid_label_->hide();
+                matrixid_input_->setValid(true);
         }
 
         try {
@@ -377,6 +383,8 @@ LoginPage::onLoginButtonClicked()
                 return;
         } else {
                 error_matrixid_label_->setText("");
+                error_matrixid_label_->hide();
+                matrixid_input_->setValid(true);
         }
 
         try {

src/ui/TextField.cpp

@@ -69,6 +69,18 @@ TextField::hasLabel() const
         return show_label_;
 }
 
+bool
+TextField::isValid() const
+{
+        return is_valid_;
+}
+
+void
+TextField::setValid(bool valid)
+{
+        is_valid_ = valid;
+}
+
 void
 TextField::setLabelFontSize(qreal size)
 {
@@ -147,7 +159,7 @@ QColor
 TextField::underlineColor() const
 {
         if (!underline_color_.isValid()) {
-                if (hasAcceptableInput() || !isModified())
+                if (TextField::isValid() || !isModified())
                         return QPalette().color(QPalette::Highlight);
                 else
                         return Qt::red;

src/ui/TextField.h

@@ -30,6 +30,7 @@ public:
         void setLabelFontSize(qreal size);
         void setShowLabel(bool value);
         void setUnderlineColor(const QColor &color);
+        void setValid(bool valid);
 
         QColor inkColor() const;
         QColor labelColor() const;
@@ -37,6 +38,7 @@ public:
         QColor backgroundColor() const;
         QString label() const;
         bool hasLabel() const;
+        bool isValid() const;
         qreal labelFontSize() const;
 
 protected:
@@ -54,6 +56,7 @@ private:
         TextFieldLabel *label_;
         TextFieldStateMachine *state_machine_;
         bool show_label_;
+        bool is_valid_;
         qreal label_font_size_;
 };