fix: fix touchscreen drag interruption issue

1. Replaced DragHandler with MouseArea for drag handling to better
support touchscreen interactions
2. Changed visibility control from `visible` to `opacity` to prevent
layout reflow during drag operations
3. Updated drag activation logic to use MouseArea's drag state instead
of DragHandler's active state
4. Simplified drag initialization by directly setting Drag.imageSource
on the root item
5. Fixed drag state synchronization by binding Drag.active to
mouseArea.drag.active

Log: Fixed touchscreen drag and drop interruption issues

Influence:
1. Test touchscreen drag operations on icon items
2. Verify drag visual feedback (opacity changes) during drag operations
3. Test drag and drop functionality with mouse input
4. Verify drag image appears correctly during drag operations
5. Test drag cancellation and completion scenarios
6. Verify no layout shifts occur during drag operations

fix: 修复触摸屏拖拽被打断的问题

1. 将 DragHandler 替换为 MouseArea 以更好地支持触摸屏交互
2. 将可见性控制从 `visible` 改为 `opacity`，防止拖拽过程中的布局重排
3. 更新拖拽激活逻辑，使用 MouseArea 的拖拽状态而非 DragHandler 的活动
状态
4. 简化拖拽初始化，直接在根项目上设置 Drag.imageSource
5. 通过将 Drag.active 绑定到 mouseArea.drag.active 来修复拖拽状态同步
问题

Log: 修复触摸屏拖拽被打断的问题

Influence:
1. 测试触摸屏上的图标拖拽操作
2. 验证拖拽过程中的视觉反馈（透明度变化）
3. 测试鼠标输入的拖放功能
4. 验证拖拽过程中拖拽图像正确显示
5. 测试拖拽取消和完成场景
6. 验证拖拽过程中没有布局偏移发生

PMS: BUG-346077

Author: 18202781743

qml/windowed/IconItemDelegate.qml

@@ -12,7 +12,7 @@ import org.deepin.launchpad 1.0
 
 Control {
     id: root
-    visible: !dragHandler.active
+    opacity: Drag.active ? 0 : 1
 
     property string text: display.startsWith("internal/category/") ? getCategoryName(display.substring(18)) : display
 
@@ -25,10 +25,11 @@ Control {
     signal menuTriggered()
 
     Drag.dragType: Drag.Automatic
+    Drag.active: mouseArea.drag.active
 
     states: State {
         name: "dragged";
-        when: dragHandler.active
+        when: mouseArea.drag.active
         // FIXME: When dragging finished, the position of the item is changed for unknown reason,
         //        so we use the state to reset the x and y here.
         PropertyChanges {
@@ -73,25 +74,17 @@ Control {
                     theme: ApplicationHelper.DarkType
                 }
 
-                DragHandler {
-                    id: dragHandler
-                    target: root
+                MouseArea {
+                    id: mouseArea
+                    anchors.fill: parent
+                    hoverEnabled: false
                     acceptedButtons: Qt.LeftButton
                     enabled: root.dndEnabled
-                    dragThreshold: 1
-                    onActiveChanged: {
-                        if (active) {
-                            // We switch to use the `dndItem` to handle Drag event since that one will always exists.
-                            // If we use the current item, then if the item that provides the drag attached property
-                            // get destoryed (e.g. switch page or folder close caused destory), dropping at that moment
-                            // will cause a crash.
-                            dndItem.Drag.hotSpot = target.Drag.hotSpot
-                            dndItem.Drag.mimeData = target.Drag.mimeData
-
+                    drag.target: root
+                    onPressed: function (mouse) {
+                        if (mouse.button === Qt.LeftButton && root.dndEnabled) {
                             appIcon.grabToImage(function(result) {
-                                dndItem.Drag.imageSource = result.url;
-                                dndItem.Drag.active = true
-                                dndItem.Drag.startDrag()
+                                root.Drag.imageSource = result.url;
                             })
                         }
                     }