我想在按下按钮时运行并杀死一个线程 [英] I want to run and kill a thread on a button press

问题描述

我有一个程序，它应该通过串行连接向 arduino 发送一些数据点，该程序将控制一些电机移动.我可以单独发送控制信号，也可以通过 txt 文件发送控制信号，该文件将重复运行，直到文件完成.在运行 txt 文件时，我希望能够像暂停或停止按钮一样退出循环.我认为最好的方法是通过我可以关闭的线程.我以前从未做过任何线程处理，我的初步尝试也没有奏效.这里是发送文件数据的函数.

I have a program that is supposed to send a few data points over a serial connection to an arduino which will control some motors to move. I can send the control signals individually as well as by txt file which will run repeatedly until the file is complete. While running a txt file, I want to be able to exit the loop like a pause or stop button. I think the best way to do that is via a thread that I can close. I have never done any threading before and my rudimentary attempts have not worked. Here is the function that sends the file data.

def send_file():
    # Global vars
    global moto1pos
    global motor2pos
    # Set Ready value
    global isready
    # Get File location
    program_file_name = file_list.get('active')
    file_path = "/home/evan/Documents/bar_text_files/"
    program_file = Path(file_path + program_file_name)
    file = open(program_file)
    pos1 = []
    pos2 = []
    speed1 = []
    speed2 = []
    accel1 = []
    accel2 = []
    for each in file:
        vals = each.split()
        pos1.append(int(vals[0]))
        pos2.append(int(vals[1]))
        speed1.append(int(vals[2]))
        speed2.append(int(vals[3]))
        accel1.append(int(vals[4]))
        accel2.append(int(vals[5]))
    # Send file values
    try:
        while isready == 1:
            for i in range(len(pos1)):
                print("Step: " + str(i+1))
                data = struct.pack("!llhhhh", pos1[i], pos2[i], speed1[i], speed2[i], accel1[i], accel2[i])
                ser.write(data)

                try:
                    pos1time = abs(pos1[i]/speed1[i])
                except:
                    pos1time = 0
                try:
                    pos2time = abs(pos2[i]/speed2[i])
                except:
                    pos2time = 0
            time_array = (pos1time, pos2time)
            time.sleep(max(time_array))
            motor1pos = ser.readline()
            motor2pos = ser.readline()
            if i < (len(pos1)-1):
                isready = ord(ser.read(1))
            else:
                isready = 0
except:
    print("Error: data not sent. Check serial port is open")

这是我希望使用 sendfile 命令工作的线程命令.

Here is the threading command which I want the sendfile command to work from.

def thread():
    try:
        global isready
        isready = 1
        t = threading.Thread(name='sending_data', target=command)
        t.start()
    except:
        print("Threading Error: you don't know what you are doing")

这是我希望线程被杀死的停止函数:

And here is the stop function I want the thread to be killed by:

def stop():
    try:
        global isready
        isready = 0
        t.kill()
    except:
        print("Error: thread wasn't killed")

我知道你不应该杀死一个线程，但数据并不是很重要.更重要的是在发生故障之前停止电机.

I know you aren't supposed to kill a thread but the data isn't very important. Whats more important is to stop the motors before something breaks.

tkinter 中的按钮是:

The button in tkinter is:

run_file_butt = tk.Button(master = file_frame, text = "Run File", command = thread)

当我单击按钮时，程序会运行，但停止功能不会停止运动.

When I click the button, the program runs but the stop function does nothing to stop the motion.

推荐答案

由于我对线程的简单理解以及我使用线程的独特环境，我的答案很简单.我没有以我希望的方式终止线程，而是在 send_file 函数的发送行中添加了另一个条件语句.

The answer I have gone with is simple due to my simple understanding of threading and unique circumstances with which I am using the threading. Instead of terminating the thread in a way I was hoping, I added another conditional statement to the sending line of the send_file function.

    while isready == 1:
        for i in range(len(pos1)):
            if motorstop == False:
                print("Step: " + str(i+1))
                #data = struct.pack('!llllhhhhhhhh', pos1[i], pos2[i], pos3[i], pos4[i], speed1[i], speed2[i], speed3[i], speed[4], accel1[i], accel2[i], accel3[i], accel4[i])
                data = struct.pack("!llhhhh", pos1[i], pos2[i], speed1[i], speed2[i], accel1[i], accel2[i])
                ser.write(data)
            else:
                isready = 0
                break

并且我已将我的 stop() 函数更新为以下内容:

and I have updated my stop() func to the following:

def stop():
    try:
        global motorstop
        global t
        motorstop = True
        t.join()
    except:
        print("Error: thread wasn't killed")

我不确定它是如何工作的，但它比@stovefl 提到的要简单得多.

I'm not exactly sure how it works but it is much simpler than what was mentioned by @stovefl.

使用这段代码，由于函数大部分只是休眠，它可以运行但不会发送任何新信息，然后在下一次迭代后将 .join() .

With this code, since the function is mostly just sleeping, it can run but it won't send any new information and then will .join() after the next iteration.

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