python - QListWidget:如何拖放插入带有图标的自定义小部件？

Question

我创建了一个自定义 QListWidget，其中添加了自定义列表小部件(在本例中只是 QPushButton 小部件)，所有设置都添加到它的 QListWidgetItems 中，以便我可以从 QPushButton 拖放，以向 QListWidget 添加另一个按钮。在第一个列表小部件中，您会注意到两个列表小部件项目之间有一条虚线，表示您可以在两个现有小部件之间拖动并插入小部件。然而，通过我的自定义列表，我失去了这种行为。我仍然可以将它们放在现有的小部件之间，但是没有像以前那样向用户提供视觉指示，即两个小部件之间将插入的水平条。有谁知道我会怎么做？您可以在下图中看到，第一个列表中的行是在两个列表之间插入项目的默认指示符。红色箭头指向我想要创建的那种自定义插入指示器。

其次，当我从自定义 QPushButton 中拖放时，它会突出显示为黑色，但再也不会返回到正常的灰色，如上图所示。我怎样才能让这个按钮恢复到默认状态？

from inspect import isclass
from shiboken2 import wrapInstance
from PySide2 import QtCore, QtGui, QtWidgets
from maya import OpenMayaUI as omui


def show_ui():
    main_win_obj = omui.MQtUtil.mainWindow()
    main_win = wrapInstance(long(main_win_obj), QtWidgets.QWidget)
    win = Test(parent=main_win)
    win.show()


class DragButton(QtWidgets.QPushButton):

    def __init__(self, parent=None, text=''):
        super(DragButton, self).__init__()
        self.setText(text)

    def mouseMoveEvent(self, event):

        if event.buttons() != QtCore.Qt.LeftButton:
            super(DragButton, self).mouseMoveEvent(event)
            return

        btn_img = self.grab()
        painter = QtGui.QPainter(btn_img)
        painter.setCompositionMode(
            painter.CompositionMode_DestinationIn
        )
        painter.fillRect(btn_img.rect(), QtGui.QColor(0, 0, 0, 127))
        painter.end()

        data = QtCore.QMimeData()
        data.setText('ReorderListAdd()')

        drag = QtGui.QDrag(self)
        drag.setMimeData(data)
        drag.setPixmap(btn_img)
        drag.setHotSpot(event.pos())
        drag.exec_(QtCore.Qt.CopyAction)

        super(DragButton, self).mouseMoveEvent(event)

    def mouseReleaseEvent(self, event):

        data = QtCore.QMimeData()
        data.setText('my text')

        drag = QtGui.QDrag(self)
        drag.setMimeData(data)
        drag.exec_()

        super(DragButton, self).mouseReleaseEvent(event)


class ReorderList(QtWidgets.QListWidget):

    def __init__(self, parent=None):
        super(ReorderList, self).__init__(parent)

        self.setDragDropMode(
            QtWidgets.QAbstractItemView.InternalMove
        )
        self.setAcceptDrops(True)
        self.setAlternatingRowColors(True)
        self.setSelectionMode(
            QtWidgets.QAbstractItemView.SingleSelection
        )
        self.setDragDropMode(
            QtWidgets.QAbstractItemView.InternalMove
        )

    def add_btn(self, text='', index=-1):

        widget = QtWidgets.QWidget()
        if not text:
            text = 'item {0}'.format(self.count() + 1)
        btn = QtWidgets.QPushButton(text)

        layout = QtWidgets.QVBoxLayout(widget)
        layout.setContentsMargins(2, 2, 2, 2)
        layout.setSpacing(2)
        layout.addWidget(btn)

        item = QtWidgets.QListWidgetItem()
        item.setSizeHint(widget.sizeHint())

        if index < 0:
            self.addItem(item)
        else:
            self.insertItem(index, item)
        self.setItemWidget(item, widget)

    def dropEvent(self, event):
        drop_index = self.indexAt(event.pos()).row()
        self.add_btn(index=drop_index)
        super(ReorderList, self).dropEvent(event)

    def dragEnterEvent(self, event):
        event.accept()

    def dragMoveEvent(self, event):
        event.accept()

    def onClick(self):
        print self.sender().text()


class Test(QtWidgets.QMainWindow):

    def __init__(self, *args, **kwargs):
        super(Test, self).__init__(*args, **kwargs)

        self.list1 = QtWidgets.QListWidget()
        self.list1.setDragDropMode(
            QtWidgets.QAbstractItemView.DragDrop
        )
        self.list1.setSelectionMode(
            QtWidgets.QAbstractItemView.SingleSelection
        )
        self.list1.setDragDropMode(
            QtWidgets.QAbstractItemView.InternalMove
        )
        self.list1.setMaximumHeight(60)
        self.list2 = ReorderList()
        self.list2.setMaximumHeight(120)
        for name in ('item 1', 'item 2', 'item 3'):
            item = QtWidgets.QListWidgetItem(name)
            self.list1.addItem(item)
            self.list2.add_btn(text=name)
        self.btn = DragButton(text='Add list button')
        self.btn.clicked.connect(self.list2.add_btn)

        self.widget = QtWidgets.QWidget()
        self.setCentralWidget(self.widget)
        self.layout = QtWidgets.QVBoxLayout(self.widget)
        for item in (self.list1, self.list2, self.btn):
            self.layout.addWidget(item)


if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    win = Test()
    win.show()
    sys.exit(app.exec_())

我希望在 QListWidget 中插入小部件时能够有一个水平条，并使已药物的按钮返回到默认颜色。

以下是我可以找到的一些类似链接，帮助我做到这一点:

• Drag'N'Drop custom widget items between QListWidgets
• PyQt QListWidget custom items
• PyQt - Add drag & drop to widget

Answer 1

由于拖放是自定义的，因此您必须进行绘制，因此您必须在 DragMoveEvent 方法中使用 QModelIndex 检测项目的矩形。然后进行绘画，但由于小部件的大小，它不会被看到，所以我看了一下，我创建了一个修改编辑器几何形状的委托(delegate)。

class Delegate(QtWidgets.QStyledItemDelegate):
    def updateEditorGeometry(self, editor, option, index):
        super(Delegate, self).updateEditorGeometry(editor, option, index)
        geo = editor.geometry().adjusted(0, 4, 0, 0)
        editor.setGeometry(geo)

class ReorderList(QtWidgets.QListWidget):
    def __init__(self, parent=None):
        super(ReorderList, self).__init__(parent)
        delegate = Delegate(self)
        self.setItemDelegate(delegate)
        self.dropIndicatorRect = QtCore.QRect()
        self.setDragDropMode(
            QtWidgets.QAbstractItemView.InternalMove
        )
        self.setAcceptDrops(True)
        self.setAlternatingRowColors(True)
        self.setSelectionMode(
            QtWidgets.QAbstractItemView.SingleSelection
        )
        self.setDragDropMode(
            QtWidgets.QAbstractItemView.InternalMove
        )

    def add_btn(self, text='', index=-1):
        widget = QtWidgets.QWidget()
        if not text:
            text = 'item {0}'.format(self.count() + 1)
        btn = QtWidgets.QPushButton(text)

        item = QtWidgets.QListWidgetItem()
        item.setSizeHint(btn.sizeHint())

        if index < 0:
            self.addItem(item)
        else:
            self.insertItem(index, item)
        self.setItemWidget(item, btn)

    def dropEvent(self, event):
        drop_index = self.indexAt(event.pos()).row()
        self.add_btn(index=drop_index)
        self.dropIndicatorRect = QtCore.QRect()
        self.viewport().update()
        super(ReorderList, self).dropEvent(event)

    def dragEnterEvent(self, event):
        event.accept()

    def dragLeaveEvent(self, event):
        self.dropIndicatorRect = QtCore.QRect()
        self.viewport().update()
        super(ReorderList, self).dragLeaveEvent(event)

    def dragMoveEvent(self, event):
        event.accept()

    def onClick(self):
        print(self.sender().text())

    def dragMoveEvent(self, event):
        index = self.indexAt(event.pos())
        if index.isValid():
            rect = self.visualRect(index)
            if self.dropIndicatorPosition() == QtWidgets.QAbstractItemView.OnItem:
                self.dropIndicatorRect = rect
            else:
                self.dropIndicatorRect = QtCore.QRect()
        else:
            self.dropIndicatorRect = QtCore.QRect()
        self.viewport().update()
        super(ReorderList, self).dragMoveEvent(event)

    def paintEvent(self, event):
        super(ReorderList, self).paintEvent(event)
        if not self.dropIndicatorRect.isNull() and self.showDropIndicator():
            painter = QtGui.QPainter(self.viewport())
            p = QtGui.QPen(painter.pen())
            p.setWidthF(1.5)
            painter.setPen(p)
            r = self.dropIndicatorRect
            painter.drawLine(r.topLeft(), r.topRight())