feat: add Apps winthin folder are dragged across pages.

Open the launcher app folder, drag the app icon on the first page to the right, leave the folder boundary (hide boundary), and drag across pages in the folder

pms-bug-288691

Author: wjyrich

qml/FolderGridViewPopup.qml

@@ -144,6 +144,72 @@ Popup {
                     Layout.fillWidth: true
                     Layout.fillHeight: true
                     color: "transparent"
+
+                    DropArea {
+                        id: folderPageDropArea
+                        property int pageIntent: 0
+                        readonly property real paddingColumns: 0.3
+                        readonly property int horizontalPadding: contentRoot.width * paddingColumns
+                        anchors.fill: parent
+
+
+                        function checkDragMove() {
+                            if (drag.x < horizontalPadding) {
+                                pageIntent = -1
+                            } else if (drag.x > (width - horizontalPadding)) {
+                                let isLastPage = folderPagesView.currentIndex === folderPagesView.count - 1
+                                if (isLastPage) {
+                                    return
+                                }
+                                pageIntent = 1
+                            } else {
+                                pageIntent = 0
+                            }
+                        }
+
+                        keys: ["text/x-dde-launcher-dnd-desktopId"]
+                        onPositionChanged: {
+                            checkDragMove()
+                        }
+                        onDropped: (drop) => {
+                            // drop over the left or right boundary of the page, do nothing
+                            if (pageIntent !== 0) {
+                                pageIntent = 0
+                                return
+                            }
+                            // drop into current page
+                            let dragId = drop.getDataAsString("text/x-dde-launcher-dnd-desktopId")
+                            dropOnPage(dragId, "internal/folders/" + folderLoader.currentFolderId, folderPagesView.currentIndex)
+                            pageIntent = 0
+                        }
+                        onExited: {
+                            pageIntent = 0
+                        }
+                        onPageIntentChanged: {
+                            if (pageIntent !== 0) {
+                                folderDndMovePageTimer.restart()
+                            } else {
+                                folderDndMovePageTimer.stop()
+                            }
+                        }
+
+                        Timer {
+                            id: folderDndMovePageTimer
+                            interval: 1000
+                            onTriggered: {
+                                if (parent.pageIntent > 0) {
+                                    incrementPageIndex(folderPagesView)
+                                } else if (parent.pageIntent < 0) {
+                                    decrementPageIndex(folderPagesView)
+                                }
+                                parent.pageIntent = 0
+                                if (folderPagesView.currentIndex !== 0) {
+                                    parent.checkDragMove()
+                                }
+                            }
+                        }
+                    }
+
                     MouseArea {
                         anchors.fill: parent
                         scrollGestureEnabled: false