在 PyQt GUI 中集成 QPainter

Question

我正在尝试在一个布局中使用 QPainter 制作的对象以及 PyQt 的本机小部件，但这样做有困难。

我尝试使用 addWidget() 将其添加到布局中，但没有成功。

class window(QWidget):
    def __init__(self):
        super().__init__()
        self.resize(600, 500)
        self.setWindowTitle('GUI 2.0')

        #LCD
        self.lcd = QLCDNumber()
        self.lcd.setFixedHeight(100)

        #Slider
        self.slider = QSlider(Qt.Horizontal)
        self.slider.setMaximum(40)
        self.slider.setMinimum(0)
        self.slider.valueChanged.connect(self.progress)

        #Push button
        pb = QPushButton('Button', self)
        pb.clicked.connect(self.button)

        #Progress Bar
        self.pbar = QProgressBar(self)
        self.pbar.setGeometry(30, 40, 200, 25)
        self.pbar.setTextVisible(False)

        #Qpainter
        painter = QPainter()
        painter.setPen(QPen(Qt.black, 5, Qt.SolidLine))
        painter.setBrush(QBrush(Qt.green, Qt.DiagCrossPattern))
        painter.drawRect(100, 15, 400,200)

        #Grid Layout 
        layout = QGridLayout()
        layout.addWidget(self.lcd, 1, 1)
        layout.addWidget(self.slider, 2, 1)
        layout.addWidget(pb, 2, 2)
        layout.addWidget(self.pbar, 0, 1)
        layout.addWidget(painter) # doesn't work!

        self.setLayout(layout)

我的目标是这样的，滑块最终会改变水箱中的水位，按钮将重置滑块值，从而清空水箱：

而我有这样的事情：

如何将画家对象添加到布局中？

Answer 1

QPainter 不是一个小部件，而只是在设备上绘画（QWidget、QImage、QPixmap 等），因此在您的情况下，您必须创建一个自定义小部件，在 paintEvent 方法中绘制坦克

from PyQt5 import QtCore, QtGui, QtWidgets


class TankWidget(QtWidgets.QWidget):
    progressChanged = QtCore.pyqtSignal(float)

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

        self._progress = 0.0

    @QtCore.pyqtProperty(float, notify=progressChanged)
    def progress(self):
        return self._progress

    @progress.setter
    def progress(self, p):
        if 0 <= p <= 1.0:
            self._progress = p
            self.progressChanged.emit(p)
            self.update()

    def paintEvent(self, event):
        painter = QtGui.QPainter(self)
        height = self.progress * self.height()

        r = QtCore.QRect(0, self.height() - height, self.width(), height)
        painter.fillRect(r, QtGui.QBrush(QtCore.Qt.blue))
        pen = QtGui.QPen(QtGui.QColor("red"), 10)
        painter.setPen(pen)
        painter.drawRect(self.rect())

    def sizeHint(self):
        return QtCore.QSize(100, 100)


class Widget(QtWidgets.QWidget):
    def __init__(self):
        super().__init__()
        self.resize(600, 500)
        self.setWindowTitle("GUI 2.0")

        self.tank = TankWidget()
        self.progressbar = QtWidgets.QProgressBar()
        self.lcd = QtWidgets.QLCDNumber()
        self.lcd.setFixedHeight(100)
        self.slider = QtWidgets.QSlider(QtCore.Qt.Horizontal, maximum=101)
        self.button = QtWidgets.QPushButton("Button")

        self.slider.valueChanged.connect(self.on_value_changed)

        lay = QtWidgets.QGridLayout(self)
        lay.addWidget(self.tank, 0, 0, 2, 1)
        lay.addWidget(QtWidgets.QLabel("Tank", alignment=QtCore.Qt.AlignCenter), 2, 0)
        lay.addWidget(self.progressbar, 0, 1)
        lay.addWidget(self.lcd, 1, 1)
        lay.addWidget(self.slider, 2, 1)
        lay.addWidget(
            QtWidgets.QLabel(
                pixmap=QtGui.QPixmap("warning.png"), alignment=QtCore.Qt.AlignCenter
            ),
            0,
            2,
            2,
            1,
        )
        lay.addWidget(self.button, 2, 2)

        self.setFixedHeight(self.sizeHint().height())

        self.slider.setValue(40)

    @QtCore.pyqtSlot()
    def on_value_changed(self):
        progress = self.slider.value() * 1.0 / self.slider.maximum()
        self.tank.progress = progress
        self.progressbar.setValue(self.slider.value())
        self.lcd.display(self.slider.value())


if __name__ == "__main__":
    import sys

    app = QtWidgets.QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())