QStateMachine 程序转换（即信号）

Question

我需要能够从不是由用户交互（即由进程完成）生成的信号（或类似的东西）更改 QStateMachine 的状态。这个例子重定向了一个用户生成的信号来演示这个想法，但还没有起作用。在这里，按钮信号触发了我想用于转换的其他信号。此处的状态是 B1 <-> B2，其中 Bi -> Bj 在按下按钮 bi 时在重定向信号上。

QStateMachine 文档似乎只涵盖基于按钮直接信号的转换，我无法推断出使用任何信号（即我创建的信号）的更一般情况。

import sys
from PySide2.QtCore import Qt, QStateMachine, QState, Signal as QSignal
from PySide2.QtWidgets import QApplication, QMainWindow, QPushButton, QVBoxLayout, QWidget

class MainWindow(QMainWindow):
    
    def __init__(self):
        QMainWindow.__init__(self)

        self.w = QWidget()
        self.setCentralWidget(self.w)
        
        l1 = QVBoxLayout()
        self.b1 = QPushButton("B1", self.w)
        self.b1.pressed.connect(self.b1Pressed)
        l1.addWidget(self.b1)
        self.b2  = QPushButton("B2", self.w)
        self.b2.pressed.connect(self.b2Pressed)
        l1.addWidget(self.b2)
        
        self.w .setLayout(l1)
        
        self.setupStateMachine()
        self.show()

    def b1Pressed(self):
        print("b1 pressed")
        self._b1Pressed.emit()
        
    def b2Pressed(self):
        print("b2 pressed")
        self._b2Pressed.emit()
            
    def setupStateMachine(self):
        
        self._b1Pressed = QSignal()
        self._b2Pressed = QSignal()
        
        self.sm = QStateMachine()
        
        self.B1 = QState()
        self.B1.assignProperty(self.b1, "enabled", True)
        self.B1.assignProperty(self.b2, "enabled", False)
        self.sm.addState(self.B1)

        self.B2 = QState()
        self.B2.assignProperty(self.b1, "enabled", False)
        self.B2.assignProperty(self.b2, "enabled", True)
        self.sm.addState(self.B2)
        
        # The point of it all:
        # change states from a signal (or program generated event)
        self.B1.addTransition(self._b1Pressed, self.B2)
        self.B2.addTransition(self._b2Pressed, self.B1)

if __name__ == '__main__':

    app = QApplication(sys.argv)
    window = MainWindow()
    sys.exit(app.exec_())

Answer 1

您的代码存在以下问题：

信号未声明为 class 的属性，但在方法的同一级别。
您还没有建立初始状态。
您还没有启动 QStateMachine。

class MainWindow(QMainWindow):
    <b>_b1Pressed = QSignal()
    _b2Pressed = QSignal()</b>

    def __init__(self):
        QMainWindow.__init__(self)

        self.w = QWidget()
        self.setCentralWidget(self.w)

        l1 = QVBoxLayout()
        self.b1 = QPushButton("B1", self.w)
        self.b1.pressed.connect(self.b1Pressed)
        l1.addWidget(self.b1)
        self.b2 = QPushButton("B2", self.w)
        self.b2.pressed.connect(self.b2Pressed)
        l1.addWidget(self.b2)

        self.w.setLayout(l1)

        self.setupStateMachine()
        self.show()

    def b1Pressed(self):
        print("b1 pressed")
        self._b1Pressed.emit()

    def b2Pressed(self):
        print("b2 pressed")
        self._b2Pressed.emit()

    def setupStateMachine(self):

        self.sm = QStateMachine()

        self.B1 = QState()
        self.B1.assignProperty(self.b1, "enabled", True)
        self.B1.assignProperty(self.b2, "enabled", False)
        self.sm.addState(self.B1)

        self.B2 = QState()
        self.B2.assignProperty(self.b1, "enabled", False)
        self.B2.assignProperty(self.b2, "enabled", True)
        self.sm.addState(self.B2)

        # The point of it all:
        # change states from a signal (or program generated event)
        self.B1.addTransition(self._b1Pressed, self.B2)
        self.B2.addTransition(self._b2Pressed, self.B1)

        <b>self.sm.setInitialState(self.B1)
        self.sm.start()</b>

QStateMachine 程序转换（即信号）

QStateMachine procedural transition (i.e. Signal)

python

qt

qstatemachine

pyside2