有没有办法在父小部件上覆盖多个项目（PySide/Qt）

Question

我有一个主要的父窗口小部件，我希望在父窗口小部件之上有几个布局。

使用父窗口小部件初始化布局会将布局放置在父窗口小部件之上。我喜欢这样，并希望为同一个父小部件多次（左侧、顶部、底部和右侧）。

我使用了具有不同子布局的 QGridLayout，但这会导致布局调整大小并迫使它们变小。最后添加的任何叠加层都应该在其他项目之上。

下面是我想要的一个非常简单的例子。

import sys
from PySide import QtGui, QtCore


class Overlay(QtGui.QBoxLayout):
    """Overlay widgets on a parent widget."""

    def __init__(self, parent=None, location="left"):
        super().__init__(QtGui.QBoxLayout.TopToBottom, parent)

        if location == "left" or location == "right":
            self.setDirection(QtGui.QBoxLayout.TopToBottom)
            if location == "right":
                self.setAlignment(QtCore.Qt.AlignRight)
        elif location == "top" or location == "bottom":
            self.setDirection(QtGui.QBoxLayout.LeftToRight)
            if location == "bottom":
                self.setAlignment(QtCore.Qt.AlignBottom)

        self.css = "QWidget {background-color: lightskyblue; color: white}"
    # end Constructor

    def addWidget(self, widget):
        super().addWidget(widget)

        widget.setStyleSheet(self.css)
    # end addWidget
# end class Overlay

def main():
    app = QtGui.QApplication(sys.argv)

    window = QtGui.QMainWindow()
    window.show()

    widg = QtGui.QTreeView()
    window.setCentralWidget(widg)

    left = Overlay(widg, "left")
    left.addWidget(QtGui.QLabel("HELLO"))
    left.addWidget(QtGui.QLabel("WORLD!"))

    top = Overlay(widg, "top")
    top.addWidget(QtGui.QLabel("Hello"))
    top.addWidget(QtGui.QLabel("World!"))

    right = Overlay(location="right")
    right.setParent(widg)
    right.addWidget(QtGui.QLabel("hello"))
    right.addWidget(QtGui.QLabel("world!"))

    return app.exec_()
# end main

if __name__ == '__main__':
    sys.exit(main())

是否有多个布局具有相同的父级？如果没有，是否有某种方法可以创建一个虚拟小部件，该小部件将与父小部件一起移动并让叠加层使用多个虚拟小部件作为其父小部件？

还有

layout = QtGui.QBoxLayout(QtGui.QBoxLayout.TopToBottom, parent_widget)

不做同样的事情

layout = QtGui.QBoxLayout(QtGui.QBoxLayout.TopToBottom)
layout.setParent(parent_widget)

初始化对不同的父级做了什么？

Answer 1

我通过创建自己的主自定义布局解决了这个问题。 OverlayCenter 将主小部件作为其父小部件，您只需将其他布局添加到此布局。

import sys
from PySide import QtGui, QtCore


class OverlayCenter(QtGui.QLayout):
    """Layout for managing overlays."""

    def __init__(self, parent):
        super().__init__(parent)

        # Properties
        self.setContentsMargins(0, 0, 0, 0)

        self.items = []
    # end Constructor

    def addLayout(self, layout):
        """Add a new layout to overlay on top of the other layouts and widgets."""
        self.addChildLayout(layout)
        self.addItem(layout)
    # end addLayout

    def __del__(self):
        """Destructor for garbage collection."""
        item = self.takeAt(0)
        while item:
            item = self.takeAt(0)
    # end Destructor

    def addItem(self, item):
        """Add an item (widget/layout) to the list."""
        self.items.append(item)
    # end addItem

    def count(self):
        """Return the number of items."""
        return len(self.items)
    # end Count

    def itemAt(self, index):
        """Return the item at the given index."""
        if index >= 0 and index < len(self.items):
            return self.items[index]

        return None
    # end itemAt

    def takeAt(self, index):
        """Remove and return the item at the given index."""
        if index >= 0 and index < len(self.items):
            return self.items.pop(index)

        return None
    # end takeAt

    def setGeometry(self, rect):
        """Set the main geometry and the item geometry."""
        super().setGeometry(rect)

        for item in self.items:
            item.setGeometry(rect)
    # end setGeometry
# end class OverlayCenter


class Overlay(QtGui.QBoxLayout):
    """Overlay widgets on a parent widget."""

    def __init__(self, location="left", parent=None):
        super().__init__(QtGui.QBoxLayout.TopToBottom, parent)

        if location == "left":
            self.setDirection(QtGui.QBoxLayout.TopToBottom)
            self.setAlignment(QtCore.Qt.AlignLeft | QtCore.Qt.AlignVCenter)
        elif location == "right":
            self.setDirection(QtGui.QBoxLayout.TopToBottom)
            self.setAlignment(QtCore.Qt.AlignRight | QtCore.Qt.AlignVCenter)
        elif location == "top":
            self.setDirection(QtGui.QBoxLayout.LeftToRight)
            self.setAlignment(QtCore.Qt.AlignTop | QtCore.Qt.AlignHCenter)
        elif location == "bottom":
            self.setDirection(QtGui.QBoxLayout.LeftToRight)
            self.setAlignment(QtCore.Qt.AlignBottom | QtCore.Qt.AlignHCenter)


        self.css = "QWidget {background-color: lightskyblue; color: white}"
    # end Constructor

    def addWidget(self, widget):
        super().addWidget(widget)

        widget.setStyleSheet(self.css)
    # end addWidget
# end class Overlay

def main():
    app = QtGui.QApplication(sys.argv)

    window = QtGui.QMainWindow()
    window.show()

    widg = QtGui.QTreeView()
    window.setCentralWidget(widg)

    left = Overlay("left")
    lhlbl = QtGui.QLabel("Hello")
    lwlbl = QtGui.QLabel("World!")
    lhlbl.setSizePolicy(QtGui.QSizePolicy.Maximum, QtGui.QSizePolicy.Maximum)
    lwlbl.setSizePolicy(QtGui.QSizePolicy.Maximum, QtGui.QSizePolicy.Maximum)
    left.addWidget(lhlbl)
    left.addWidget(lwlbl)

    top = Overlay("top")
    lhlbl = QtGui.QLabel("HELLO")
    lwlbl = QtGui.QLabel("WORLD!")
    lhlbl.setSizePolicy(QtGui.QSizePolicy.Maximum, QtGui.QSizePolicy.Maximum)
    lwlbl.setSizePolicy(QtGui.QSizePolicy.Maximum, QtGui.QSizePolicy.Maximum)
    top.addWidget(lhlbl)
    top.addWidget(lwlbl)

    right = Overlay("right")
    lhlbl = QtGui.QLabel("hellO")
    lwlbl = QtGui.QLabel("worlD!")
    lhlbl.setSizePolicy(QtGui.QSizePolicy.Maximum, QtGui.QSizePolicy.Maximum)
    lwlbl.setSizePolicy(QtGui.QSizePolicy.Maximum, QtGui.QSizePolicy.Maximum)
    right.addWidget(lhlbl)
    right.addWidget(lwlbl)

    bottom = Overlay("bottom")
    lhlbl = QtGui.QLabel("hello")
    lwlbl = QtGui.QLabel("world!")
    lhlbl.setSizePolicy(QtGui.QSizePolicy.Maximum, QtGui.QSizePolicy.Maximum)
    lwlbl.setSizePolicy(QtGui.QSizePolicy.Maximum, QtGui.QSizePolicy.Maximum)
    bottom.addWidget(lhlbl)
    bottom.addWidget(lwlbl)

    center = OverlayCenter(widg)
    center.addLayout(left)
    center.addLayout(top)
    center.addLayout(right)
    center.addLayout(bottom)

    return app.exec_()
# end main

if __name__ == '__main__':
    sys.exit(main())