Question

我试图举一个简单的例子来帮助理解QSignalMapping的概念在PySide中的工作方式。我想通过循环遍历来动态创建一系列按钮，当用户按下其中一个按钮时，我可以激活一种方法，该方法返回所按下按钮的相应标签。

from PySide2 import QtWidgets,QtCore,QtGui

fruit_list = ["apples","oranges","pears"]

def fruit_button_event():
    print "this is the pressed button's label"

def main():
    for fruit in fruit_list:
        fruit_button = QtWidgets.QPushButton(fruit)
        fruit_button.clicked.connect(lambda:fruit_button_event())
main()

Answer 1

在下一部分中，我将显示一个示例如何使用QSignalMapper：

from PySide2 import QtCore, QtWidgets


class Widget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)
        lay = QtWidgets.QVBoxLayout(self)

        fruit_list = ["apples","oranges","pears"]
        mapper =  QtCore.QSignalMapper(self)
        mapper.mapped[str].connect(self.fruit_button_event)

        for fruit in fruit_list:
            btn = QtWidgets.QPushButton(fruit)
            btn.clicked.connect(mapper.map)
            mapper.setMapping(btn, fruit)
            lay.addWidget(btn)

    @QtCore.Slot(str)
    def fruit_button_event(self, text):
        print("this is the pressed button's label", text)


if __name__ == '__main__':
    import sys

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

请记住，不推荐使用Qt 5.10 QSignalMapper中的内容：

该课程已过时。提供它是为了保留旧的源代码   工作。强烈建议您不要在新代码中使用它。

可以通过 functools.partial（...）获得python中相同的功能：

from PySide2 import QtCore, QtWidgets
from functools import partial


class Widget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)
        lay = QtWidgets.QVBoxLayout(self)

        fruit_list = ["apples","oranges","pears"]

        for fruit in fruit_list:
            btn = QtWidgets.QPushButton(fruit)
            btn.clicked.connect(partial(self.fruit_button_event, fruit))
            lay.addWidget(btn)

    @QtCore.Slot(str)
    def fruit_button_event(self, text):
        print("this is the pressed button's label", text)

或使用lambda：

btn.clicked.connect(lambda text=fruit: self.fruit_button_event(text))

或QButtonGroup：

class Widget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)
        lay = QtWidgets.QVBoxLayout(self)

        fruit_list = ["apples","oranges","pears"]
        group = QtWidgets.QButtonGroup(self)
        group.buttonClicked.connect(self.OnButtonClicked)

        for fruit in fruit_list:
            btn = QtWidgets.QPushButton(fruit)
            group.addButton(btn)
            lay.addWidget(btn)

    @QtCore.Slot(QtWidgets.QAbstractButton)
    def OnButtonClicked(self, btn):
        print("this is the pressed button's label", btn.text())

使用PySide和QSignalMapper

1 个答案: