PyQt5 图像和 QGridlayout

Question

我有一个小部件，它想显示带有QLabel 和QCheckBox 的图像。创建了 4 个类，每个类都包含一些要放在最终屏幕上的信息。 Class Grid 对齐和网格图像、文本和复选框。

脚本运行后获取当前屏幕。当前小部件中没有图像。

图片在哪里？

想要的画面

代码

import sys, os
from PyQt5 import QtCore, QtGui, QtWidgets

iconroot = os.path.dirname(__file__)

class ImageWidget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(ImageWidget, self).__init__(parent)

        self.hlay = QtWidgets.QHBoxLayout(self)
        buckling_ilabel = QtWidgets.QLabel(self)
        pixmap = QtGui.QPixmap(os.path.join(iconroot, "images/fixed-fixed.png"))
        buckling_ilabel.resize(150, 150)
        buckling_ilabel.setPixmap(pixmap.scaled(buckling_ilabel.size(), QtCore.Qt.KeepAspectRatio))
        self.hlay.addWidget(buckling_ilabel)

        buckling_blabel = QtWidgets.QLabel(self)
        pixmap = QtGui.QPixmap(os.path.join(iconroot, "images/pinned-pinned.png"))
        buckling_blabel.resize(150, 150)
        buckling_blabel.setPixmap(pixmap.scaled(buckling_blabel.size(), QtCore.Qt.KeepAspectRatio))
        self.hlay.addWidget(buckling_blabel)

        buckling_clabel = QtWidgets.QLabel(self)
        pixmap = QtGui.QPixmap(os.path.join(iconroot, "images/fixed-free.png"))
        buckling_clabel.resize(150, 150)
        buckling_clabel.setPixmap(pixmap.scaled(buckling_clabel.size(), QtCore.Qt.KeepAspectRatio))
        self.hlay.addWidget(buckling_clabel)

        buckling_dlabel = QtWidgets.QLabel(self)
        pixmap = QtGui.QPixmap(os.path.join(iconroot, "images/fixed-pinned.png"))
        buckling_dlabel.resize(150, 150)
        buckling_dlabel.setPixmap(pixmap.scaled(buckling_dlabel.size(), QtCore.Qt.KeepAspectRatio))
        self.hlay.addWidget(buckling_dlabel)
        self.setLayout(self.hlay)



class EffLengthInfo(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(EffLengthInfo, self).__init__(parent)

        ilabel = QtWidgets.QLabel('Ley = 1.0 L\nLec = 1.0 L')
        blabel = QtWidgets.QLabel('Ley = 0.699 L\nLec = 0.699 L')
        clabel = QtWidgets.QLabel('Ley = 2.0 L\nLec = 2.0 L')   
        dlabel = QtWidgets.QLabel('Ley = 0.5 L\nLec = 0.5 L')

        self.ilay = QtWidgets.QHBoxLayout()
        self.ilay.addWidget(ilabel)
        self.ilay.addWidget(blabel)
        self.ilay.addWidget(clabel)
        self.ilay.addWidget(dlabel)


class CheckInfo(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(CheckInfo, self).__init__(parent)

        icheck = QtWidgets.QCheckBox()
        bcheck = QtWidgets.QCheckBox()
        ccheck = QtWidgets.QCheckBox()
        dcheck = QtWidgets.QCheckBox()

        self.checklay = QtWidgets.QHBoxLayout()
        self.checklay.addWidget(icheck, alignment=QtCore.Qt.AlignCenter)
        self.checklay.addWidget(bcheck, alignment=QtCore.Qt.AlignCenter)
        self.checklay.addWidget(ccheck, alignment=QtCore.Qt.AlignCenter)
        self.checklay.addWidget(dcheck, alignment=QtCore.Qt.AlignCenter)



class Grid(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Grid, self).__init__(parent)

        self.imagewidget = ImageWidget()
        self.efflengthinfo = EffLengthInfo()
        self.checkinfo = CheckInfo()

        vlay = QtWidgets.QVBoxLayout(self)
        vlay.addLayout(self.imagewidget.hlay)
        vlay.addLayout(self.efflengthinfo.ilay)
        vlay.addLayout(self.checkinfo.checklay)
        self.setLayout(vlay)



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

Answer 1

线路：vlay.addLayout (self.imagewidget.hlay)

错误是：QLayout :: addChildLayout: layout "" already has a parent

试试看：

import sys, os
from PyQt5 import QtCore, QtGui, QtWidgets

iconroot = os.path.dirname(__file__)

class ImageWidget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(ImageWidget, self).__init__(parent)

#        self.hlay = QtWidgets.QHBoxLayout(self)
        self.hlay = QtWidgets.QHBoxLayout()                       # < --- -self
        buckling_ilabel = QtWidgets.QLabel(self)
        pixmap = QtGui.QPixmap(os.path.join(iconroot, "images/logo.png"))
        buckling_ilabel.resize(150, 150)
        buckling_ilabel.setPixmap(pixmap.scaled(buckling_ilabel.size(), QtCore.Qt.KeepAspectRatio))
        self.hlay.addWidget(buckling_ilabel)

        buckling_blabel = QtWidgets.QLabel(self)
        pixmap = QtGui.QPixmap(os.path.join(iconroot, "images/logo.png"))
        buckling_blabel.resize(150, 150)
        buckling_blabel.setPixmap(pixmap.scaled(buckling_blabel.size(), QtCore.Qt.KeepAspectRatio))
        self.hlay.addWidget(buckling_blabel)

        buckling_clabel = QtWidgets.QLabel(self)
        pixmap = QtGui.QPixmap(os.path.join(iconroot, "images/logo.png"))
        buckling_clabel.resize(150, 150)
        buckling_clabel.setPixmap(pixmap.scaled(buckling_clabel.size(), QtCore.Qt.KeepAspectRatio))
        self.hlay.addWidget(buckling_clabel)

        buckling_dlabel = QtWidgets.QLabel(self)
        pixmap = QtGui.QPixmap(os.path.join(iconroot, "images/logo.png"))
        buckling_dlabel.resize(150, 150)
        buckling_dlabel.setPixmap(pixmap.scaled(buckling_dlabel.size(), QtCore.Qt.KeepAspectRatio))
        self.hlay.addWidget(buckling_dlabel)

#        self.setLayout(self.hlay)                                  # < ---




class EffLengthInfo(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(EffLengthInfo, self).__init__(parent)

        ilabel = QtWidgets.QLabel('Ley = 1.0 L\nLec = 1.0 L')
        blabel = QtWidgets.QLabel('Ley = 0.699 L\nLec = 0.699 L')
        clabel = QtWidgets.QLabel('Ley = 2.0 L\nLec = 2.0 L')   
        dlabel = QtWidgets.QLabel('Ley = 0.5 L\nLec = 0.5 L')

        self.ilay = QtWidgets.QHBoxLayout()
        self.ilay.addWidget(ilabel)
        self.ilay.addWidget(blabel)
        self.ilay.addWidget(clabel)
        self.ilay.addWidget(dlabel)


class CheckInfo(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(CheckInfo, self).__init__(parent)

        icheck = QtWidgets.QCheckBox()
        bcheck = QtWidgets.QCheckBox()
        ccheck = QtWidgets.QCheckBox()
        dcheck = QtWidgets.QCheckBox()

        self.checklay = QtWidgets.QHBoxLayout()
        self.checklay.addWidget(icheck, alignment=QtCore.Qt.AlignCenter)
        self.checklay.addWidget(bcheck, alignment=QtCore.Qt.AlignCenter)
        self.checklay.addWidget(ccheck, alignment=QtCore.Qt.AlignCenter)
        self.checklay.addWidget(dcheck, alignment=QtCore.Qt.AlignCenter)



class Grid(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Grid, self).__init__(parent)

        self.imagewidget   = ImageWidget()
        self.efflengthinfo = EffLengthInfo()
        self.checkinfo     = CheckInfo()

        vlay = QtWidgets.QVBoxLayout(self) 

        vlay.addLayout(self.imagewidget.hlay)                            # < ---
        # Error: QLayout::addChildLayout: layout "" already has a parent # < ---

        vlay.addLayout(self.efflengthinfo.ilay)
        vlay.addLayout(self.checkinfo.checklay)
        self.setLayout(vlay)



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

Answer 2

The @S.Nick's solution 有效，但它不是正确的，除了它没有解释问题，它只指示您应该提供的错误消息。

你的第一个错误是你没有一致的设计，例如，即使一个小部件是一个视觉元素，它不仅意味着它是唯一的，它还有相关的数据，所以我问自己: 你为什么要创建ImageWidget 类，同样的事情？对于EffLengthInfo 和CheckInfo？好吧，似乎只是为了创建一个布局，是否有必要创建一个小部件来创建一个布局？不，因为小部件是不必要的资源，即浪费内存。因此，我指出S.Nick's solution是不正确的，因为他是在邀请其他人重叠设计错误。

如果您的目标只是创建布局，那么最好使用函数：

import sys, os
from PyQt5 import QtCore, QtGui, QtWidgets

iconroot = os.path.dirname(__file__)

def create_image_layout():
        hlay = QtWidgets.QHBoxLayout()
        for icon_name in ("images/fixed-fixed.png", 
                          "images/pinned-pinned.png",
                          "images/fixed-free.png",
                          "images/fixed-pinned.png"):

            label = QtWidgets.QLabel()
            pixmap = QtGui.QPixmap(os.path.join(iconroot, icon_name))
            label.resize(150, 150)
            label.setPixmap(pixmap.scaled(label.size(), QtCore.Qt.KeepAspectRatio))
            hlay.addWidget(label)
        return hlay

def create_EffLengthInfo_layout():
    hlay = QtWidgets.QHBoxLayout()
    for text in ('Ley = 1.0 L\nLec = 1.0 L',
                 'Ley = 0.699 L\nLec = 0.699 L',
                 'Ley = 2.0 L\nLec = 2.0 L',
                 'Ley = 0.5 L\nLec = 0.5 L'):
        label = QtWidgets.QLabel(text)
        hlay.addWidget(label)
    return hlay

def create_checkInfo_layout():
    hlay = QtWidgets.QHBoxLayout()
    for _ in range(3):
        checkbox = QtWidgets.QCheckBox()
        hlay.addWidget(checkbox, alignment=QtCore.Qt.AlignCenter)
    return hlay

class Grid(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Grid, self).__init__(parent)

        image_lay = create_image_layout()
        efflengthinfo_lay = create_EffLengthInfo_layout()
        checkinfo_lay = create_checkInfo_layout()

        vlay = QtWidgets.QVBoxLayout(self)
        vlay.addLayout(image_lay)
        vlay.addLayout(efflengthinfo_lay)
        vlay.addLayout(checkinfo_lay)


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

---

为什么在 EffLengthInfo 和 CheckInfo “有效”的情况下显示？

我指出它在引号中起作用，因为它起作用但它不是解决方案，直截了当，布局是在布局中建立的，它是小部件的一部分，之后它不能放在另一个中小部件，如果我们检查ImageWidget，我们会看到您已经为小部件建立了两次布局：

class ImageWidget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(ImageWidget, self).__init__(parent)

        self.hlay = QtWidgets.QHBoxLayout(self) # 1.
        ...
        self.setLayout(self.hlay) # 2.

1. 当您在构建布局时设置小部件时，它会在该小部件中设置。

2. 当小部件使用setLayout()方法设置布局时

因此，您应该在vlay.addLayout(self.imagewidget.hlay) 行中抛出以下错误：

QLayout::addChildLayout: layout "" 已经有一个父级

另一种解决方案是设置小部件而不是布局：

class ImageWidget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(ImageWidget, self).__init__(parent)
        self.hlay = QtWidgets.QHBoxLayout(self)
        ...
        # self.setLayout(self.hlay) # comment this line

class EffLengthInfo(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(EffLengthInfo, self).__init__(parent)
        ...
        self.ilay = QtWidgets.QHBoxLayout(self) # <-- add self

class CheckInfo(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(CheckInfo, self).__init__(parent)
        ...
        self.checklay = QtWidgets.QHBoxLayout(self)  # <-- add self

class Grid(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Grid, self).__init__(parent)
        self.imagewidget = ImageWidget()
        self.efflengthinfo = EffLengthInfo()
        self.checkinfo = CheckInfo()

        vlay = QtWidgets.QVBoxLayout(self)
        vlay.addWidget(self.imagewidget)  # <-- change addLayout() to addWidget()
        vlay.addWidget(self.efflengthinfo) # <-- change addLayout() to addWidget()
        vlay.addWidget(self.checkinfo) # <-- change addLayout() to addWidget()
        ...

---

您可能会想到的另一种观点，这取决于您要赋予小部件的用途，即您希望信息单元是图像、文本和复选框，因此如果创建小部件是正确的：

import sys, os
from PyQt5 import QtCore, QtGui, QtWidgets

iconroot = os.path.dirname(__file__)


class FooWidget(QtWidgets.QWidget):
    def __init__(self, path_icon, text, checked=False, parent=None):
        super(FooWidget, self).__init__(parent)
        lay = QtWidgets.QVBoxLayout(self)

        pixmap = QtGui.QPixmap(os.path.join(iconroot, path_icon))
        pixmap_label = QtWidgets.QLabel()
        pixmap_label.resize(150, 150)
        pixmap_label.setPixmap(pixmap.scaled(pixmap_label.size(), QtCore.Qt.KeepAspectRatio))

        text_label = QtWidgets.QLabel(text)
        checkbox = QtWidgets.QCheckBox(checked=checked)

        lay.addWidget(pixmap_label)
        lay.addWidget(text_label)
        lay.addWidget(checkbox)


class Grid(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Grid, self).__init__(parent)

        lay = QtWidgets.QHBoxLayout(self)

        icons = ["images/fixed-fixed.png", 
                 "images/pinned-pinned.png",
                 "images/fixed-free.png",
                 "images/fixed-pinned.png"]

        texts = ["Ley = 1.0 L\nLec = 1.0 L",
                 "Ley = 0.699 L\nLec = 0.699 L",
                 "Ley = 2.0 L\nLec = 2.0 L",
                 "Ley = 0.5 L\nLec = 0.5 L"]

        for path_icon, text in zip(icons, texts):
            w = FooWidget(os.path.join(iconroot, path_icon), text)
            lay.addWidget(w)


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