Add CancelSelectBox() method to <select> element, see #566

This reverts the value to the one set when the selection box was opened. This is particularly helpful for use cases where e.g. the "Escape" key should cancel the selection. Added example usage to the demo sample.
mikke89 · Oct 31, 2024 · 347773b · 347773b
1 parent b32980a
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Showing 6 changed files with 44 additions and 3 deletions.
diff --git a/Include/RmlUi/Core/Elements/ElementFormControlSelect.h b/Include/RmlUi/Core/Elements/ElementFormControlSelect.h
@@ -67,7 +67,7 @@ class RMLUICORE_API ElementFormControlSelect : public ElementFormControl {
 	int GetSelection() const;
 
 	/// Returns one of the select control's option elements.
-	/// @param[in] The index of the desired option.
+	/// @param[in] index The index of the desired option.
 	/// @return The option element or nullptr if the index was out of bounds.
 	Element* GetOption(int index);
 	/// Returns the number of options in the select control.
@@ -93,11 +93,13 @@ class RMLUICORE_API ElementFormControlSelect : public ElementFormControl {
 
 	/// Removes all options from the select control.
 	void RemoveAll();
-	
+
 	/// Show the selection box.
 	void ShowSelectBox();
 	/// Hide the selection box.
 	void HideSelectBox();
+	/// Revert to the value selected when the selection box was opened, then hide the box.
+	void CancelSelectBox();
 	/// Check whether the select box is opened or not.
 	bool IsSelectBoxVisible();
 

diff --git a/Samples/basic/demo/data/demo.rml b/Samples/basic/demo/data/demo.rml
@@ -867,7 +867,7 @@ form .nav-auto, form input.checkbox, form input.radio
 		</div>
 		<h2>Subject</h2>
 		<div>
-			<select name="subject">
+			<select name="subject" onkeydown="cancel_selection_on_escape">
 				<option value="none" selected>Choose your subject</option>
 				<option value="feature">Feature request</option>
 				<option value="bug">Bug report</option>

diff --git a/Samples/basic/demo/src/DemoEventListener.cpp b/Samples/basic/demo/src/DemoEventListener.cpp
@@ -29,6 +29,7 @@
 #include "DemoWindow.h"
 #include <RmlUi/Core/Element.h>
 #include <RmlUi/Core/Elements/ElementFormControl.h>
+#include <RmlUi/Core/Elements/ElementFormControlSelect.h>
 #include <RmlUi_Backend.h>
 
 DemoEventListener::DemoEventListener(const Rml::String& value, Rml::Element* element, DemoWindow* demo_window) :
@@ -178,6 +179,18 @@ void DemoEventListener::ProcessEvent(Rml::Event& event)
 			demo_window->SetSandboxStylesheet(value);
 		}
 	}
+	else if (value == "cancel_selection_on_escape")
+	{
+		if (event.GetParameter("key_identifier", 0) == Input::KeyIdentifier ::KI_ESCAPE)
+		{
+			auto select_control = rmlui_dynamic_cast<Rml::ElementFormControlSelect*>(element);
+			if (select_control && select_control->IsSelectBoxVisible())
+			{
+				select_control->CancelSelectBox();
+				event.StopPropagation();
+			}
+		}
+	}
 }
 
 void DemoEventListener::OnDetach(Rml::Element* /*element*/)

diff --git a/Source/Core/Elements/ElementFormControlSelect.cpp b/Source/Core/Elements/ElementFormControlSelect.cpp
@@ -119,6 +119,10 @@ void ElementFormControlSelect::HideSelectBox()
 {
 	widget->HideSelectBox();
 }
+void ElementFormControlSelect::CancelSelectBox()
+{
+	widget->CancelSelectBox();
+}
 
 bool ElementFormControlSelect::IsSelectBoxVisible()
 {

diff --git a/Source/Core/Elements/WidgetDropDown.cpp b/Source/Core/Elements/WidgetDropDown.cpp
@@ -634,6 +634,10 @@ void WidgetDropDown::ProcessEvent(Event& event)
 
 void WidgetDropDown::ShowSelectBox()
 {
+	if (box_visible)
+		return;
+
+	selected_value_on_box_open = parent_element->GetAttribute<String>("value", "");
 	selection_element->SetProperty(PropertyId::Visibility, Property(Style::Visibility::Visible));
 	selection_element->SetPseudoClass("checked", true);
 	value_element->SetPseudoClass("checked", true);
@@ -647,6 +651,9 @@ void WidgetDropDown::ShowSelectBox()
 
 void WidgetDropDown::HideSelectBox()
 {
+	if (!box_visible)
+		return;
+
 	selection_element->SetProperty(PropertyId::Visibility, Property(Style::Visibility::Hidden));
 	selection_element->RemoveProperty(PropertyId::Height);
 	selection_element->SetPseudoClass("checked", false);
@@ -657,6 +664,17 @@ void WidgetDropDown::HideSelectBox()
 	box_visible = false;
 }
 
+void WidgetDropDown::CancelSelectBox()
+{
+	if (!box_visible)
+		return;
+
+	if (parent_element->GetAttribute<String>("value", "") != selected_value_on_box_open)
+		parent_element->SetAttribute("value", selected_value_on_box_open);
+
+	HideSelectBox();
+}
+
 bool WidgetDropDown::IsSelectBoxVisible()
 {
 	return box_visible;

diff --git a/Source/Core/Elements/WidgetDropDown.h b/Source/Core/Elements/WidgetDropDown.h
@@ -104,6 +104,8 @@ class WidgetDropDown : public EventListener {
 	void ShowSelectBox();
 	/// Hides the selection box.
 	void HideSelectBox();
+	/// Revert to the value selected when the selection box was opened, then hide the box.
+	void CancelSelectBox();
 	/// Check whether the select box is visible or not.
 	bool IsSelectBoxVisible();
 
@@ -119,6 +121,8 @@ class WidgetDropDown : public EventListener {
 	Element* selection_element;
 	Element* value_element;
 
+	String selected_value_on_box_open;
+
 	bool lock_selection = false;
 	bool selection_dirty = false;
 	bool value_rml_dirty = false;