Question

嗨，我是python和gtk编程的新手我正在编写一个程序来做一些测量。为了绘制测量值，我使用了matplotlib 该程序将具有打开和关闭加热器并进行测量的功能我想为加热器和测量使用单独的螺纹目前，该程序尚未实现与硬件的通信。

问题是当我点击“测量按钮”时，“进度条”不再起作用。我收到一条消息：

gtk.ProgressBar对象位于0x29b8460（未初始化为0x0）

当我只使用加热器按钮时，进度条会继续工作

我做错了什么？

这是代码

#!/usr/bin/env python

import pygtk
pygtk.require('2.0')
import gtk
import time
import gobject
import threading
import matplotlib
import numpy as np
from matplotlib.backends.backend_gtkagg import FigureCanvasGTKAgg as FigureCanvas

class measure:
    # callback to quit
    def delete_event(self, widget, event, data = None):
        gtk.main_quit()
        return False

    def heater_helper(self, widget, heater, progressbar):
        print "starting heater thread"
        threading.Thread(target=self.heater_cb, args=(widget, heater, progressbar)).start()

    def heater_cb(self, widget, heater, progressbar):
        heaterstring = "6.3"
        heater = eval(heaterstring)
        stap = 1
        j = 0.1
        heatervalue = widget.get_active()
        print heatervalue
        progressbar.set_fraction(0.1)
        while (stap <= 10 ):
            if widget.get_active():
                print widget.get_active()
                fraction = j * stap
                print fraction
                progressbar.set_fraction(fraction)
                stap = stap + 1
                time.sleep(1)
            else:
                stap = 11
                progressbar.set_fraction(0.0)
                break

    def do_measurement_helper(self, widget, fig):
        print " Start measurement thread"
        threading.Thread(target=self.do_measurement, args=(widget, fig)).start()

    def do_measurement(self, widget, fig):
        fig.clear()
        ax = fig.add_subplot(111)
        x = np.arange(0, 5*np.pi, 0.01)
        y = np.sin(x**2)*np.exp(-x)
        ax.plot(x, y)
        fig.canvas.draw()

    def __init__(self):
        # Create new Window
        self.window = gtk.Window(gtk.WINDOW_TOPLEVEL)
        self.window.connect("delete_event", self.delete_event)
        self.window.show()

        mainbox = gtk.HBox(False, 0)
        self.window.add(mainbox)
        mainbox.show()

        leftvbox = gtk.VBox(False, spacing = 10)
        mainbox.pack_start(leftvbox, expand = False, fill = False, padding = 0)
        leftvbox.show()

        rightvbox = gtk.VBox(False, spacing = 10)
        mainbox.pack_start(rightvbox, expand = False, fill = False, padding =0)
        rightvbox.show()

        heaterprogressbar = gtk.ProgressBar()
        leftvbox.pack_start(heaterprogressbar, expand = False, fill = False, padding = 0)
        heaterprogressbar.show()
        heaterbutton = gtk.ToggleButton("Heater")
        leftvbox.pack_start(heaterbutton, expand = True, fill = False, padding = 0)
        heaterbutton.show()
        heaterbutton.connect("toggled", self.heater_helper, heaterbutton, heaterprogressbar)

        fig = matplotlib.figure.Figure(figsize=(5,4), dpi=64)
        canvas = FigureCanvas(fig)
        rightvbox.pack_start(canvas, expand = True, fill = True, padding = 0 )
        canvas.show()
        measurebutton = gtk.Button("Measure")
        rightvbox.pack_start(measurebutton, expand = False, fill = False, padding = 0)
        measurebutton.show()
        measurebutton.connect("clicked", self.do_measurement_helper, fig)

def main():
    gtk.main()
    return(0)

if __name__ == "__main__":
    gtk.gdk.threads_init()
    measure()
    main()
    gtk.gdk.threads_leave()

亲切的问候，

Joris Weijters

Answer 1

可能不支持组合线程，Matplotlib和GTK主循环，并且难以准确调试正在发生的事情。我的建议是不要从线程进行任何GUI调用，而是使用gobject.idle_add()来安排它们。

Answer 2

线程，Matplotlib和GTK主循环可以组合，如果你记住一些事情：

我使用gobject.threads_init()代替gtk.gdk.threads_init()，gtk.gdk变体与Matplotlib结合使用对我不起作用。我想你也可以省略gtk.gdk.threads_leave()。

正如ptomato所提到的，你应该让主要的gtk线程通过调用gobject.idle_add()和gobject.timeout_add()函数处理与gtk小部件有关的任何事情。我通常会创建一个辅助函数来定期从float变量更新状态栏：

def do_measurement(self):
    self.data = []
    self.progress = 0
    self.abort = threading.Event()
    gobject.timeout_add(100, self.update_progressbar)
    for point in some_generator_yielding_100_values():
        if self.abort.is_set():
            break
        self.data.append(point)
        self.progress += 0.01
    self.progress = None

def update_progressbar(self):
    if self.progress is None:
        self.progressbar.set_fraction(0) # reset bar
        return False           # do not run again
    self.progressbar.set_fraction(self.progress)
    return True                # run again after 100ms

def start_measurement(self):
    threading.Thread(target=self.do_measurement).start()

def stop_measurement(self):
    self.abort.set()

但您当然也可以致电gobject.idle_add(self.progressbar.set_fraction, x)以异步设置新值x。

在matplot事件之后，gtk progressbar不再工作了吗？

2 个答案: