From 521469185e7db8295785f5deb71fddfc8d69b5c4 Mon Sep 17 00:00:00 2001
From: zhangkun <zhangkun2@uniontech.com>
Date: Mon, 28 Sep 2026 18:33:23 +0800
Subject: [PATCH] fix(ComboBox): size popup before it is mapped
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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1. Size the window popup from the model and the measured delegate height, instead of
   the content item, which has not been laid out yet when the window is created.
2. Measure the delegate height in ArrowListView by realizing one item while the popup
   is still closed, and pin the scroll-arrow height so the layout settles in one pass.
3. Keep the style item height only as the viewport that makes that first measurement
   possible.

Log: ComboBox popups appear at their final size instead of being resized after being mapped.
Influence: Removes the popup size jump with Window popup type.

fix(ComboBox): 弹窗按最终尺寸显示

1. 窗口弹窗改用模型与实测行高计算尺寸，不再使用尚未布局的内容项。
2. ArrowListView 在弹窗关闭时提前实例化一项以量出行高，并固定箭头条高度，使布局一次到位。
3. 样式行高仅作为首次测量所需的引导视口。

Log: 下拉弹窗显示时即为其最终尺寸，不再在显示后改变尺寸。
PMS: BUG-370839
Influence: 修复 Window 类型弹窗的尺寸跳动。
---
 qt6/src/qml/ArrowListView.qml | 16 ++++++++++++++--
 qt6/src/qml/ComboBox.qml      |  3 +++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/qt6/src/qml/ArrowListView.qml b/qt6/src/qml/ArrowListView.qml
index f6b2eace5..eb7c880c2 100644
--- a/qt6/src/qml/ArrowListView.qml
+++ b/qt6/src/qml/ArrowListView.qml
@@ -15,6 +15,17 @@ FocusScope {
     property int itemHeight:  DS.Style.arrowListView.itemHeight
     property alias view: itemsView
 
+    // Full height of the list, to size a popup before it is mapped.
+    readonly property real sizedHeight: {
+        if (itemsView.count === 0)
+            return 0
+        const item = itemsView.itemAtIndex(0)
+        const measured = itemsView.contentHeight > 0 && item ? (item.height || item.implicitHeight) : 0
+        const arrowStrips = itemsView.count > maxVisibleItems
+                ? 2 * (DS.Style.arrowListView.stepButtonIconSize.height + contentLayout.spacing) : 0
+        return Math.min(itemsView.count, maxVisibleItems) * (measured > 0 ? measured : itemHeight) + arrowStrips
+    }
+
     implicitWidth: Math.max(DS.Style.arrowListView.width, contentLayout.implicitWidth)
     implicitHeight: contentLayout.implicitHeight
 
@@ -25,7 +36,7 @@ FocusScope {
             visible: itemsView.interactive
             Layout.alignment: Qt.AlignHCenter
             Layout.fillWidth: true
-            Layout.preferredHeight: implicitHeight
+            Layout.preferredHeight: DS.Style.arrowListView.stepButtonIconSize.height
             view: itemsView
             stepSize: control.itemHeight
             direction: P.ArrowListViewButton.UpButton
@@ -36,6 +47,7 @@ FocusScope {
             clip: true
             Layout.fillWidth: true
             Layout.fillHeight: true
+            onHeightChanged: if (height > 0 && contentHeight === 0) forceLayout()
             implicitHeight: itemsView.count > 0 ? Math.min(contentHeight, maxVisibleItems * contentHeight / itemsView.count) : 0
             implicitWidth:{
                 var maxWidth = DS.Style.arrowListView.width
@@ -81,7 +93,7 @@ FocusScope {
             visible: itemsView.interactive
             Layout.alignment: Qt.AlignHCenter
             Layout.fillWidth: true
-            Layout.preferredHeight: implicitHeight
+            Layout.preferredHeight: DS.Style.arrowListView.stepButtonIconSize.height
             view: itemsView
             stepSize: control.itemHeight
             direction: P.ArrowListViewButton.DownButton
diff --git a/qt6/src/qml/ComboBox.qml b/qt6/src/qml/ComboBox.qml
index cb35c3c38..9f3d53416 100644
--- a/qt6/src/qml/ComboBox.qml
+++ b/qt6/src/qml/ComboBox.qml
@@ -173,6 +173,9 @@ T.ComboBox {
         rightMargin: DS.Style.popup.margin
         palette: control.palette
         implicitWidth: control.flat ? Math.max(contentItem.implicitWidth, control.width) : control.width
+        // 60 is a temporary viewport so the list can realize one row and be measured.
+        implicitHeight: (contentItem.sizedHeight > 0 ? contentItem.sizedHeight : 2 * DS.Style.arrowListView.itemHeight)
+                        + topPadding + bottomPadding
         onClosed: control.isInteractingWithContent = false
         Connections {
             target: control