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问PyQt5: QTreeWidget中项目对等点之间的拖放
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Stack Overflow用户

提问于 2022-07-14 09:58:00

回答 1查看 165关注 0票数 1

可以拖动和阻止同一级别的节点彼此进入，而不是其他父节点。

我在QTreeWidget中覆盖了dragMoveEvent和dropEvent方法，我只有正确的second layer效果，它可以互相拖动，防止进入对方。但是first and third levels有不同的错误。例如，节点1-1-1和节点1-2-2不能相互拖动。Node1可以拖动到Node2中，这不符合我完成的要求。

class TreeWidget(QTreeWidget):
def __init__(self):
    super().__init__()
    self.setDragDropMode(QTreeWidget.InternalMove)

def dragMoveEvent(self, event):
    current_item = self.currentItem()
    item = self.itemAt(event.pos())

    if current_item and current_item.type() == 0:
        super().dragMoveEvent(event)
    elif item and item.type() == 1 and current_item.parent() == item.parent():
        super().dragMoveEvent(event)
    elif item and item.type() == 2 and current_item.parent() == item.parent():
        super().dragMoveEvent(event)
    else:
        event.ignore()

def dropEvent(self, event):
    current_item = self.currentItem()
    item = self.itemAt(event.pos())
    if current_item and current_item.type() == 0:
        super(TreeWidget, self).dropEvent(event)
    elif item and item.type() == 1 and current_item.parent() == item.parent():
        super(TreeWidget, self).dropEvent(event)
    elif item and item.type() == 2 and current_item.parent() == item.parent():
        super(TreeWidget, self).dropEvent(event)
    else:
        event.ignore()


class BasicTreeTest1(QMainWindow):
  def __init__(self):
    super().__init__()
    self.setWindowTitle('QTreeWidget')
    self.tree = TreeWidget()

    root1 = QTreeWidgetItem(self.tree,type=0)
    root1.setText(0, 'node1')

    child1_1 = QTreeWidgetItem(root1,type=1)
    child1_1.setText(0, 'node1-1')
    child1_1.setFlags(child1_1.flags() & ~Qt.ItemIsDropEnabled)

    child1_2 = QTreeWidgetItem(root1, type=1)
    child1_2.setText(0, 'node1-2')
    child1_2.setFlags(child1_2.flags() & ~Qt.ItemIsDropEnabled)

    child1_1_1 = QTreeWidgetItem(child1_1, type=2)
    child1_1_1.setText(0, 'node1-1-1')
    child1_1_1.setFlags(child1_1_1.flags() & ~Qt.ItemIsDropEnabled)

    child1_2_1 = QTreeWidgetItem(child1_1, type=2)
    child1_2_1.setText(0, 'node1-2-1')
    child1_2_1.setFlags(child1_2_1.flags() & ~Qt.ItemIsDropEnabled)


    root2 = QTreeWidgetItem(self.tree,type=0)
    root2.setText(0, 'node2')


    child2_1 = QTreeWidgetItem(root2, type=1)
    child2_1.setText(0, 'node2-1')
    child2_1.setFlags(child2_1.flags() & ~Qt.ItemIsDropEnabled)

    child2_2 = QTreeWidgetItem(root2, type=1)
    child2_2.setText(0, 'node2-2')
    child2_2.setFlags(child2_2.flags() & ~Qt.ItemIsDropEnabled)

    root3 = QTreeWidgetItem(self.tree, type=0)
    root3.setText(0, 'node3')

    child3_1 = QTreeWidgetItem(root3, type=1)
    child3_1.setText(0, 'node3_1')
    child3_1.setFlags(child3_1.flags() & ~Qt.ItemIsDropEnabled)

    child3_2 = QTreeWidgetItem(root3, type=1)
    child3_2.setText(0, 'node3_2')
    child3_2.setFlags(child3_2.flags() & ~Qt.ItemIsDropEnabled)

    child3_2_1 = QTreeWidgetItem(child3_2, type=2)
    child3_2_1.setText(0, 'node3-2-1')
    child3_2_1.setFlags(child3_2_1.flags() & ~Qt.ItemIsDropEnabled)

    child3_2_2 = QTreeWidgetItem(child3_2, type=2)
    child3_2_2.setText(0, 'node3-2-2')
    child3_2_2.setFlags(child3_2_2.flags() & ~Qt.ItemIsDropEnabled)
    # root1.setFlags(root1.flags() & ~Qt.ItemIsDropEnabled)
    # root2.setFlags(root2.flags() & ~Qt.ItemIsDropEnabled)
    # root3.setFlags(root3.flags() & ~Qt.ItemIsDropEnabled)
    # child22.setFlags(child22.flags() & ~Qt.ItemIsDropEnabled)
    self.setCentralWidget(self.tree)
    self.tree.expandAll()

if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = BasicTreeTest1()
    w.show()
    sys.exit(app.exec_())

这个网站是我的参考：id/文章/详细信息/125258736

python

pyqt5

drag-and-drop

qtreewidget

回答 1

Stack Overflow用户

回答已采纳

发布于 2022-07-17 12:19:41

更新

由于您的最新编辑更改了需求，因此需要一种不同的方法。目前，我唯一能看到的解决方案是得到当前的跌落指示器，这样就有可能知道目标是否在某一项之上或下方。Qt为此使用了一个私有方法，必须将其移植到PyQt以访问相同的功能。我已经在下面的演示脚本中实现了这一点，它只允许在自己的父级内重新排序兄弟项目(在任何级别)：

import sys
from PyQt5.QtCore import *
from PyQt5.QtWidgets import *

class TreeWidget(QTreeWidget):
    def __init__(self):
        super().__init__()
        self.setDragDropMode(QTreeWidget.InternalMove)

    def dragMoveEvent(self, event):
        if self.canDrop(event):
            super().dragMoveEvent(event)
        else:
            event.ignore()

    def dropEvent(self, event):
        if self.canDrop(event):
            super().dropEvent(event)
        else:
            event.ignore()

    def canDrop(self, event):
        target = self.itemAt(event.pos())
        current = self.currentItem()
        if target is not None and target.parent() is current.parent():
            index = self.indexFromItem(target)
            indicator = self.dragIndicator(
                event.pos(), self.visualItemRect(target), index)
            return (indicator == QAbstractItemView.AboveItem or
                    indicator == QAbstractItemView.BelowItem)
        return False

    def dragIndicator(self, pos, rect, index):
        indicator = QAbstractItemView.OnViewport
        if not self.dragDropOverwriteMode():
            margin = int(max(2, min(rect.height() / 5.5, 12)))
            if pos.y() - rect.top() < margin:
                indicator = QAbstractItemView.AboveItem
            elif rect.bottom() - pos.y() < margin:
                indicator = QAbstractItemView.BelowItem
            elif rect.contains(pos, True):
                indicator = QAbstractItemView.OnItem
        else:
            touching = rect.adjust(-1, -1, 1, 1)
            if touching.contains(pos, False):
                indicator = QAbstractItemView.OnItem
        if (indicator == QAbstractItemView.OnItem and
            not self.model().flags(index) & Qt.ItemIsDropEnabled):
            if pos.y() < rect.center().y():
                indicator = QAbstractItemView.AboveItem
            else:
                indicator = QAbstractItemView.BelowItem
        return indicator

class BasicTreeTest1(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('QTreeWidget')
        self.tree = TreeWidget()
        root1 = QTreeWidgetItem(self.tree,type=0)
        root1.setText(0, 'node1')
        child1_1 = QTreeWidgetItem(root1,type=1)
        child1_1.setText(0, 'node1-1')
        child1_2 = QTreeWidgetItem(root1, type=1)
        child1_2.setText(0, 'node1-2')
        child1_1_1 = QTreeWidgetItem(child1_1, type=2)
        child1_1_1.setText(0, 'node1-1-1')
        child1_2_1 = QTreeWidgetItem(child1_1, type=2)
        child1_2_1.setText(0, 'node1-2-1')
        root2 = QTreeWidgetItem(self.tree,type=0)
        root2.setText(0, 'node2')
        child2_1 = QTreeWidgetItem(root2, type=1)
        child2_1.setText(0, 'node2-1')
        child2_2 = QTreeWidgetItem(root2, type=1)
        child2_2.setText(0, 'node2-2')
        root3 = QTreeWidgetItem(self.tree, type=0)
        root3.setText(0, 'node3')
        child3_1 = QTreeWidgetItem(root3, type=1)
        child3_1.setText(0, 'node3_1')
        child3_2 = QTreeWidgetItem(root3, type=1)
        child3_2.setText(0, 'node3_2')
        child3_2_1 = QTreeWidgetItem(child3_2, type=2)
        child3_2_1.setText(0, 'node3-2-1')
        child3_2_2 = QTreeWidgetItem(child3_2, type=2)
        child3_2_2.setText(0, 'node3-2-2')
        self.setCentralWidget(self.tree)
        self.tree.expandAll()

if __name__ == '__main__':

    app = QApplication(sys.argv)
    w = BasicTreeTest1()
    w.setGeometry(600, 100, 500, 400)
    w.show()
    sys.exit(app.exec_())

前解

若要防止子项目彼此掉落，您可以使用更改其项目标志。默认标志包括Qt.ItemIsDropEnabled，因此只需删除：

child111 = QTreeWidgetItem(root1, type=1)
child111.setFlags(child111.flags() & ~Qt.ItemIsDropEnabled)

当然，这不会阻止父母之间拖放项目，但是通过重新实现dragMoveEvent和dropEvent，您的当前代码已经阻止了这一点，因此看起来上面的更改就足够了。

下面是一个基于代码的完整的工作示例：

from PyQt5 import QtCore, QtWidgets

class TreeWidget(QtWidgets.QTreeWidget):
    def __init__(self):
        super().__init__()
        self.setDragDropMode(QtWidgets.QTreeWidget.InternalMove)

    def dragMoveEvent(self, event):
        current_item = self.currentItem()
        item = self.itemAt(event.pos())

        if item and item.type() == 1 and current_item.parent() == item.parent():
            super().dragMoveEvent(event)
        else:
            event.ignore()

    def dropEvent(self, event):
        current_item = self.currentItem()
        item = self.itemAt(event.pos())
        if item and item.type() == 1 and current_item.parent() == item.parent():
            super(TreeWidget, self).dropEvent(event)
        else:
            event.ignore()

class Window(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        self.tree = TreeWidget()
        layout = QtWidgets.QVBoxLayout(self)
        layout.addWidget(self.tree)

        root1 = QtWidgets.QTreeWidgetItem(self.tree,type=0)
        root1.setText(0, '1')

        child111 = QtWidgets.QTreeWidgetItem(root1,type=1)
        child111.setFlags(child111.flags() & ~QtCore.Qt.ItemIsDropEnabled)
        child111.setText(0, '11')

        child12 = QtWidgets.QTreeWidgetItem(root1, type=1)
        child12.setFlags(child12.flags() & ~QtCore.Qt.ItemIsDropEnabled)
        child12.setText(0, '12')

        root2 = QtWidgets.QTreeWidgetItem(self.tree,type=0)
        root2.setText(0, '2')

        child121 = QtWidgets.QTreeWidgetItem(root2, type=1)
        child121.setFlags(child121.flags() & ~QtCore.Qt.ItemIsDropEnabled)
        child121.setText(0, '21')

        child122 = QtWidgets.QTreeWidgetItem(root2, type=1)
        child122.setFlags(child122.flags() & ~QtCore.Qt.ItemIsDropEnabled)
        child122.setText(0, '22')

        self.tree.expandAll()

if __name__ == '__main__':

    app = QtWidgets.QApplication(['Test'])
    window = Window()
    window.setWindowTitle('Test')
    window.setGeometry(600, 100, 300, 200)
    window.show()
    app.exec_()

票数 2

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/72978651

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