python - 从 Qrunnable 连接一个 pyqtSignal

Question

我正在尝试制作一个监控硬件的应用程序，我想使用 Qthreadpool 而不是为每个小部件设置一个线程，但我在连接信号以显示输出时遇到了问题。我也没有收到任何错误。

我的旧代码运行良好并使用 QThread 显示它应该显示的内容:

import sys
from PyQt4 import QtCore, QtGuiimport ui
import time
import mem_stats


class MainClass(QtGui.QMainWindow, ui.Ui_MainWindow):
        def __init__(self, parent= None):
        super(MainClass, self).__init__(parent)
        self.setupUi(self)
        self.mem_worker = MemWorker()
        self.mem_worker.start()
        self.connect(self.mem_worker, QtCore.SIGNAL('MEM_STATS'),self.show_mem_stats)

    def show_mem_stats(self, free_mem):
        self.free_memory_lcd.display(free_mem)


class MemWorker(QtCore.QThread):
    def __init__(self):
    super(MemWorker, self).__init__()

    def run(self):
        while True:
            free_mem = mem_stats.free_mem()
            self.emit(QtCore.SIGNAL('MEM_STATS'), free_mem)
            time.sleep(1)


if __name__ == '__main__':
    a = QtGui.QApplication(sys.argv)
    app = MainClass()
    app.show()
    sys.exit(a.exec_())

但是当我将 MemWorker 类更改为 QRunnable 时，代码运行时没有错误，但 QlcdNumber 不显示任何内容。

这是我的新代码:

import sys
from PyQt4 import QtCore, QtGui
import ui
import time
import mem_stats


class WorkerSignals(QtCore.QObject):
    mem_signal = QtCore.pyqtSignal(int)


class MainClass(QtGui.QMainWindow, ui.Ui_MainWindow):
    def __init__(self, parent= None):
        super(MainClass, self).__init__(parent)
        self.setupUi(self)
        self.mem_worker = MemWorker()
        self.thread_pool = QtCore.QThreadPool()
        self.thread_pool.setMaxThreadCount(2)
        self.connect(self.mem_worker.signal, QtCore.SIGNAL('MEM_STATS'), self.show_mem_stats)

    def show_mem_stats(self, free_mem):
        self.free_memory_lcd.display(free_mem)
        self.thread_pool.start(self.mem_worker)


class MemWorker(QtCore.QRunnable):
    def __init__(self):
        super(MemWorker, self).__init__()
        self.signal = WorkerSignals()

    def run(self):
        while True:
            free_mem = mem_stats.free_mem()
            self.signal.mem_signal.emit(QtCore.SIGNAL('MEM_STATS'), free_mem)
            time.sleep(1)


if __name__ == '__main__':
    a = QtGui.QApplication(sys.argv)
    app = MainClass()
    app.show()
    sys.exit(a.exec_())

Answer 1

问题是你没有启动QRunnable，你想在插槽中启动它，如果QRunnable没有启动，它永远不会被调用。另一方面，目前推荐使用the new connection syntax。 ，最后推荐使用@pyqtSlot decorator从 C++ 端建立连接，以更少的资源使其更快。

from PyQt4 import QtCore, QtGui
import ui
import time
import mem_stats

class WorkerSignals(QtCore.QObject):
    mem_signal = QtCore.pyqtSignal(int)


class MainClass(QtGui.QMainWindow, ui.Ui_MainWindow):
    def __init__(self, parent= None):
        super(MainClass, self).__init__(parent)
        self.setupUi(self)
        self.mem_worker = MemWorker()
        self.thread_pool = QtCore.QThreadPool()
        self.thread_pool.setMaxThreadCount(2)
        self.mem_worker.signal.mem_signal.connect(self.show_mem_stats)
        self.thread_pool.start(self.mem_worker)

    @QtCore.pyqtSlot(int)
    def show_mem_stats(self, free_mem):
        self.free_memory_lcd.display(free_mem)


class MemWorker(QtCore.QRunnable):
    def __init__(self):
        super(MemWorker, self).__init__()
        self.signal = WorkerSignals()

    def run(self):
        while True:
            ree_mem = mem_stats.free_mem()
            self.signal.mem_signal.emit(free_mem)
            time.sleep(1)


if __name__ == '__main__':
    import sys
    a = QtGui.QApplication(sys.argv)
    app = MainClass()
    app.show()
    sys.exit(a.exec_())