Question

我是PyQt4的新手，我正在使用QSlider制作一个gui。

默认情况下，QSlider不会显示您的刻度值。我搜索并没有找到一个简单的方法来做到这一点，所以它可能还是我必须手工制作？

Answer 1

可悲的是，没有简单的方法可以做到这一点。你必须手动完成它。我也必须这样做，所以你可以实现我的实现。考虑到我只重新实现了我需要的东西，我在一些方面进行了修改，并且valueChanged（）API表现出了截然不同的行为。

from PyQt4 import QtCore
from PyQt4.QtGui import QSlider, QWidget, QVBoxLayout, QHBoxLayout, QLabel
__author__ = 'Andres'


class QCustomSlider(QWidget):
    def __init__(self, sliderOrientation=None):
        super(QCustomSlider, self).__init__()
        self._slider = QSlider(sliderOrientation)

        self.setLayout(QVBoxLayout())

        self._labelTicksWidget = QWidget(self)
        self._labelTicksWidget.setLayout(QHBoxLayout())
        self._labelTicksWidget.layout().setContentsMargins(0, 0, 0, 0)

        self.layout().addWidget(self._slider)
        self.layout().addWidget(self._labelTicksWidget)

    def setTickLabels(self, listWithLabels):
        lengthOfList = len(listWithLabels)
        for index, label in enumerate(listWithLabels):
            label = QLabel(str(label))
            label.setContentsMargins(0, 0, 0, 0)
            if index > lengthOfList/3:
                label.setAlignment(QtCore.Qt.AlignCenter)
            if index > 2*lengthOfList/3:
                label.setAlignment(QtCore.Qt.AlignRight)
            self._labelTicksWidget.layout().addWidget(label)

    def setRange(self, mini, maxi):
        self._slider.setRange(mini, maxi)

    def setPageStep(self, value):
        self._slider.setPageStep(value)

    def setTickInterval(self, value):
        self._slider.setTickInterval(value)

    def setTickPosition(self, position):
        self._slider.setTickPosition(position)

    def setValue(self, value):
        self._slider.setValue(value)

    def onValueChangedCall(self, function):
        self._slider.valueChanged.connect(function)

Answer 2

我已经提出了一种解决方案，该解决方案涉及在垂直或水平方向上向滑块添加标签。

结果截图：

此处的代码（请注意，PyQt4和5之间有一些导入更改）。

import sys
from PyQt5 import QtWidgets
from PyQt5.QtGui import QPainter
from PyQt5.QtWidgets import QStyle, QStyleOptionSlider
from PyQt5.QtCore import QRect, QPoint, Qt


class LabeledSlider(QtWidgets.QWidget):
    def __init__(self, minimum, maximum, interval=1, orientation=Qt.Horizontal,
            labels=None, parent=None):
        super(LabeledSlider, self).__init__(parent=parent)

        levels=range(minimum, maximum+interval, interval)
        if labels is not None:
            if not isinstance(labels, (tuple, list)):
                raise Exception("<labels> is a list or tuple.")
            if len(labels) != len(levels):
                raise Exception("Size of <labels> doesn't match levels.")
            self.levels=list(zip(levels,labels))
        else:
            self.levels=list(zip(levels,map(str,levels)))

        if orientation==Qt.Horizontal:
            self.layout=QtWidgets.QVBoxLayout(self)
        elif orientation==Qt.Vertical:
            self.layout=QtWidgets.QHBoxLayout(self)
        else:
            raise Exception("<orientation> wrong.")

        # gives some space to print labels
        self.left_margin=10
        self.top_margin=10
        self.right_margin=10
        self.bottom_margin=10

        self.layout.setContentsMargins(self.left_margin,self.top_margin,
                self.right_margin,self.bottom_margin)

        self.sl=QtWidgets.QSlider(orientation, self)
        self.sl.setMinimum(minimum)
        self.sl.setMaximum(maximum)
        self.sl.setValue(minimum)
        if orientation==Qt.Horizontal:
            self.sl.setTickPosition(QtWidgets.QSlider.TicksBelow)
            self.sl.setMinimumWidth(300) # just to make it easier to read
        else:
            self.sl.setTickPosition(QtWidgets.QSlider.TicksLeft)
            self.sl.setMinimumHeight(300) # just to make it easier to read
        self.sl.setTickInterval(interval)
        self.sl.setSingleStep(1)

        self.layout.addWidget(self.sl)

    def paintEvent(self, e):

        super(LabeledSlider,self).paintEvent(e)

        style=self.sl.style()
        painter=QPainter(self)
        st_slider=QStyleOptionSlider()
        st_slider.initFrom(self.sl)
        st_slider.orientation=self.sl.orientation()

        length=style.pixelMetric(QStyle.PM_SliderLength, st_slider, self.sl)
        available=style.pixelMetric(QStyle.PM_SliderSpaceAvailable, st_slider, self.sl)

        for v, v_str in self.levels:

            # get the size of the label
            rect=painter.drawText(QRect(), Qt.TextDontPrint, v_str)

            if self.sl.orientation()==Qt.Horizontal:
                # I assume the offset is half the length of slider, therefore
                # + length//2
                x_loc=QStyle.sliderPositionFromValue(self.sl.minimum(),
                        self.sl.maximum(), v, available)+length//2

                # left bound of the text = center - half of text width + L_margin
                left=x_loc-rect.width()//2+self.left_margin
                bottom=self.rect().bottom()

                # enlarge margins if clipping
                if v==self.sl.minimum():
                    if left<=0:
                        self.left_margin=rect.width()//2-x_loc
                    if self.bottom_margin<=rect.height():
                        self.bottom_margin=rect.height()

                    self.layout.setContentsMargins(self.left_margin,
                            self.top_margin, self.right_margin,
                            self.bottom_margin)

                if v==self.sl.maximum() and rect.width()//2>=self.right_margin:
                    self.right_margin=rect.width()//2
                    self.layout.setContentsMargins(self.left_margin,
                            self.top_margin, self.right_margin,
                            self.bottom_margin)

            else:
                y_loc=QStyle.sliderPositionFromValue(self.sl.minimum(),
                        self.sl.maximum(), v, available, upsideDown=True)

                bottom=y_loc+length//2+rect.height()//2+self.top_margin-3
                # there is a 3 px offset that I can't attribute to any metric

                left=self.left_margin-rect.width()
                if left<=0:
                    self.left_margin=rect.width()+2
                    self.layout.setContentsMargins(self.left_margin,
                            self.top_margin, self.right_margin,
                            self.bottom_margin)

            pos=QPoint(left, bottom)
            painter.drawText(pos, v_str)

        return


if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    frame=QtWidgets.QWidget()
    ha=QtWidgets.QHBoxLayout()
    frame.setLayout(ha)

    w = LabeledSlider(1, 10 , 1, orientation=Qt.Horizontal)

    ha.addWidget(w)
    frame.show()
    sys.exit(app.exec_())

带有刻度标签的Python PyQt4滑块

2 个答案: