关于此代码的问题:使用 QThreadPool 的多线程 PyQt 应用程序 https://www.learnpyqt.com/courses/concurrent-execution/multithreading-pyqt-applications-qthreadpool/
从下面的代码中,如何将附加参数传递给execute_this_fn
from oh_no
功能 ?
如果我像参数一样直接传递:
worker = Worker(self.execute_this_fn(arg1, arg2))
并照常接受:
def execute_this_fn(self, progress_callback, a ,b):
我收到错误:
结果 = self.fn(*self.args, **self.kwargs) 类型错误:
execute_this_fn() 获得参数“progress_callback”的多个值
甚至有评论说“路径任何参数和 kwargs 来运行函数”,但是正确的语法是什么?
文章中的可执行代码:
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
import time
import traceback, sys
class WorkerSignals(QObject):
'''
Defines the signals available from a running worker thread.
Supported signals are:
finished
No data
error
`tuple` (exctype, value, traceback.format_exc() )
result
`object` data returned from processing, anything
progress
`int` indicating % progress
'''
finished = pyqtSignal()
error = pyqtSignal(tuple)
result = pyqtSignal(object)
progress = pyqtSignal(int)
class Worker(QRunnable):
'''
Worker thread
Inherits from QRunnable to handler worker thread setup, signals and wrap-up.
:param callback: The function callback to run on this worker thread. Supplied args and
kwargs will be passed through to the runner.
:type callback: function
:param args: Arguments to pass to the callback function
:param kwargs: Keywords to pass to the callback function
'''
def __init__(self, fn, *args, **kwargs):
super(Worker, self).__init__()
# Store constructor arguments (re-used for processing)
self.fn = fn
self.args = args
self.kwargs = kwargs
self.signals = WorkerSignals()
# Add the callback to our kwargs
self.kwargs['progress_callback'] = self.signals.progress
@pyqtSlot()
def run(self):
'''
Initialise the runner function with passed args, kwargs.
'''
# Retrieve args/kwargs here; and fire processing using them
try:
result = self.fn(*self.args, **self.kwargs)
except:
traceback.print_exc()
exctype, value = sys.exc_info()[:2]
self.signals.error.emit((exctype, value, traceback.format_exc()))
else:
self.signals.result.emit(result) # Return the result of the processing
finally:
self.signals.finished.emit() # Done
class MainWindow(QMainWindow):
def __init__(self, *args, **kwargs):
super(MainWindow, self).__init__(*args, **kwargs)
self.counter = 0
layout = QVBoxLayout()
self.l = QLabel("Start")
b = QPushButton("DANGER!")
b.pressed.connect(self.oh_no)
layout.addWidget(self.l)
layout.addWidget(b)
w = QWidget()
w.setLayout(layout)
self.setCentralWidget(w)
self.show()
self.threadpool = QThreadPool()
print("Multithreading with maximum %d threads" % self.threadpool.maxThreadCount())
self.timer = QTimer()
self.timer.setInterval(1000)
self.timer.timeout.connect(self.recurring_timer)
self.timer.start()
def progress_fn(self, n):
print("%d%% done" % n)
def execute_this_fn(self, progress_callback):
for n in range(0, 5):
time.sleep(1)
progress_callback.emit(n*100/4)
return "Done."
def print_output(self, s):
print(s)
def thread_complete(self):
print("THREAD COMPLETE!")
def oh_no(self):
# Pass the function to execute
worker = Worker(self.execute_this_fn) # Any other args, kwargs are passed to the run function
worker.signals.result.connect(self.print_output)
worker.signals.finished.connect(self.thread_complete)
worker.signals.progress.connect(self.progress_fn)
# Execute
self.threadpool.start(worker)
def recurring_timer(self):
self.counter +=1
self.l.setText("Counter: %d" % self.counter)
app = QApplication([])
window = MainWindow()
app.exec_()