問題描述

我正在嘗試制作一個在后臺與多個 BLE 設備進行通信的 UI.為此，我實現了一個運行 asyncio.loop 的單獨線程.這是必要的，因為我使用 bleak 0.9.1 連接到設備.

I'm trying to make a UI which communicates in the background with several BLE devices. For that I've implemented a separate thread which runs an asyncio.loop. This is necessary because I use bleak 0.9.1 to connect to the devices.

使用信號和槽將數據從 UI 線程獲取到工作線程可以正常工作.但是，它在另一個方向上不起作用.據我所知，這是因為線程忙于運行循環并且永遠不會停止這樣做.因此，它無法處理來自 UI 線程的輸入.

Using signals and slots to get data from the UI-thread to the worker thread works fine. However, it does not work in the other direction. As far as I know this is because the thread is busy running the loop and never stops doing that. Therefore, it cannot process the inputs from the UI-thread.

下面有一個顯示問題的示例代碼.

Below there is an example code which shows the problem.

有什么方法可以在運行 asyncio 循環的同時處理線程中的輸入槽?

Is there any way to process the input slots in the thread while running the asyncio loop?

import sys
from PyQt5.QtWidgets import QWidget, QPushButton, QApplication, QVBoxLayout
from PyQt5.QtCore import QThread, QObject, pyqtSignal, pyqtSlot
import asyncio

class Test_Thread(QObject):
    signal_back = pyqtSignal(int)

    def __init__(self,
                 loop: asyncio.AbstractEventLoop,
                 parent=None):
        super(Test_Thread, self).__init__(parent)
        self.text = "Task1 not configured"
        self.loop = loop
        self.counter = 0

    @pyqtSlot(str)
    def set_text_slot(self, txt):
        self.text = txt

    async def do_stuff1(self):
        while True:
            print(self.text)
            await asyncio.sleep(2.0)

    async def do_stuff2(self):
        while True:
            self.counter += 1
            self.signal_back.emit(self.counter)
            await asyncio.sleep(1.0)

    def work(self):
        #run the event loop
        try:
            asyncio.ensure_future(self.do_stuff1(), loop=self.loop)
            asyncio.ensure_future(self.do_stuff2(), loop=self.loop)
            self.loop.run_forever()
        finally:
            print("Disconnect...")


class Window(QWidget):

    set_text_signal = pyqtSignal(str)

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

    def initUi(self):
        layout = QVBoxLayout()
        self.button = QPushButton('User input')
        self.button.clicked.connect(self.sendtotask)
        layout.addWidget(self.button)
        self.setLayout(layout)
        self.show()

    def startThread(self):
        loop = asyncio.get_event_loop()
        self.asyciothread = Test_Thread(loop)
        self.thread = QThread()
        self.asyciothread.moveToThread(self.thread)

        self.set_text_signal.connect(self.asyciothread.set_text_slot)
        self.asyciothread.signal_back.connect(self.receivefromthread)
        self.thread.started.connect(self.asyciothread.work)

        self.thread.start()

    @pyqtSlot(int)
    def receivefromthread(self, number):
        print(str(number))

    def sendtotask(self):
        self.set_text_signal.emit("Task: Configured")


if __name__ == "__main__":
    app = QApplication(sys.argv)
    ui = Window()
    ui.show()
    sys.exit(app.exec_())

推薦答案

Qt 不需要使用線程來使用 asyncio，因為有 asyncqt 和 qasync 啟用它:

It is not necessary to use threads to use asyncio with Qt since there are libraries like asyncqt and qasync that enable it:

import asyncio
import sys

from PyQt5.QtWidgets import QWidget, QPushButton, QApplication, QVBoxLayout
from PyQt5.QtCore import QObject, pyqtSignal, pyqtSlot

from asyncqt import QEventLoop
# from qasync import QEventLoop


class Worker(QObject):
    signal_back = pyqtSignal(int)

    def __init__(self, loop: asyncio.AbstractEventLoop, parent=None):
        super(Worker, self).__init__(parent)
        self.text = "Task1 not configured"
        self.loop = loop
        self.counter = 0

    @pyqtSlot(str)
    def set_text_slot(self, txt):
        self.text = txt

    async def do_stuff1(self):
        while True:
            print(self.text)
            await asyncio.sleep(2.0)

    async def do_stuff2(self):
        while True:
            self.counter += 1
            self.signal_back.emit(self.counter)
            await asyncio.sleep(1.0)

    def work(self):
        asyncio.ensure_future(self.do_stuff1(), loop=self.loop)
        asyncio.ensure_future(self.do_stuff2(), loop=self.loop)


class Window(QWidget):
    set_text_signal = pyqtSignal(str)

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

    def initUi(self):
        layout = QVBoxLayout(self)
        self.button = QPushButton("User input")
        self.button.clicked.connect(self.sendtotask)
        layout.addWidget(self.button)

    def start_task(self):
        loop = asyncio.get_event_loop()
        self.worker = Worker(loop)
        self.set_text_signal.connect(self.worker.set_text_slot)
        self.worker.signal_back.connect(self.receive_from_worker)
        self.worker.work()

    @pyqtSlot(int)
    def receive_from_worker(self, number):
        print(str(number))

    def sendtotask(self):
        self.set_text_signal.emit("Task: Configured")


if __name__ == "__main__":
    app = QApplication(sys.argv)
    loop = QEventLoop(app)
    asyncio.set_event_loop(loop)
    ui = Window()
    ui.show()
    with loop:
        loop.run_forever()

這篇關于在單獨的線程中運行異步循環，信號來自和循環的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！