Improvements to popup positioning for ComboBox within HorizontalLayout. (#11846)

Expand ratio and spacing can cause ComboBox to miscalculate its own
position while layouting is still ongoing. Popup should not be
repositioned in such circumstances in order to avoid incorrect
intermediate states.

Continues on #11718

1 files changed, 77 insertions, 0 deletions

diff --git a/uitest/src/main/java/com/vaadin/tests/components/combobox/ComboBoxWithinHorizontalLayout.java b/uitest/src/main/java/com/vaadin/tests/components/combobox/ComboBoxWithinHorizontalLayout.java
new file mode 100644
index 0000000000..4ae8977a8b
--- /dev/null
+++ b/uitest/src/main/java/com/vaadin/tests/components/combobox/ComboBoxWithinHorizontalLayout.java
@@ -0,0 +1,77 @@
+package com.vaadin.tests.components.combobox;
+
+import java.util.Arrays;
+import java.util.Iterator;
+
+import com.vaadin.server.VaadinRequest;
+import com.vaadin.tests.components.AbstractTestUI;
+import com.vaadin.ui.Alignment;
+import com.vaadin.ui.Button;
+import com.vaadin.ui.ComboBox;
+import com.vaadin.ui.Component;
+import com.vaadin.ui.HorizontalLayout;
+
+public class ComboBoxWithinHorizontalLayout extends AbstractTestUI {
+
+    private ComboBox<String> comboBox;
+
+    @Override
+    protected void setup(VaadinRequest request) {
+        comboBox = new ComboBox<>();
+        comboBox.setWidth("100%");
+        comboBox.setPopupWidth(null);
+        populateWithShortItems();
+
+        HorizontalLayout content = new HorizontalLayout(new Button("1"),
+                new Button("2"), comboBox, new Button("3"));
+        content.setWidth("100%");
+        content.setExpandRatio(comboBox, 2.0f);
+        Iterator<Component> i = content.iterator();
+        while (i.hasNext()) {
+            content.setComponentAlignment(i.next(), Alignment.BOTTOM_RIGHT);
+        }
+
+        getLayout().setSpacing(true);
+        addComponent(content);
+        addComponent(new Button("Toggle items", e -> {
+            if ("Short items".equals(comboBox.getCaption())) {
+                populateWithLongItems();
+            } else {
+                populateWithShortItems();
+            }
+        }));
+        addComponent(new Button("Toggle spacing", e -> {
+            content.setSpacing(!content.isSpacing());
+        }));
+        addComponent(new Button("Toggle expand ratio", e -> {
+            if (content.getExpandRatio(comboBox) > 0.0f) {
+                content.setExpandRatio(comboBox, 0.0f);
+            } else {
+                content.setExpandRatio(comboBox, 2.0f);
+            }
+        }));
+    }
+
+    private void populateWithLongItems() {
+        comboBox.setCaption("Long items");
+        comboBox.setItems(Arrays.asList(
+                "First very, very, very, very, very long item to add",
+                "Second very long item to add", "Third very long item to add"));
+    }
+
+    private void populateWithShortItems() {
+        comboBox.setCaption("Short items");
+        comboBox.setItems(Arrays.asList("short1", "short2", "short3"));
+    }
+
+    @Override
+    protected Integer getTicketNumber() {
+        return 11718;
+    }
+
+    @Override
+    protected String getTestDescription() {
+        return "ComboBox within HorizontalLayout should not get incorrect "
+                + "intermediate popup positions that cause flickering.";
+    }
+}