如何在PyQt中将按钮设置为键盘中断

Question

在终端运行程序时，我们可以通过按 'Ctrl+c' 来停止程序，这时会显示一个消息叫 'KeyboardInterrupt'。那么，有没有办法在 PyQt 中通过点击一个按钮来实现同样的效果呢？

Answer 1

在我的脚本中，为了中断一个无限循环，我使用了 QtGui.qApp.processEvents()，效果很好。这个无限循环会从串口读取数据并写入数据，用户可以通过按一个按钮来中断这个循环（1. 条件）。

def Move_Right(self):

    # move the slide right
    cmdPack = struct.pack(cmdStruct, Address, Rotate_Right, 0, Motor5, Speed5)
    dataByte = bytearray(cmdPack)
    checksumInt = sum(dataByte[:]) % 256
    msgPack = struct.pack(msgStruct, Address, Rotate_Right, 0, Motor5, Speed5, checksumInt)
    ser0.flushOutput() # Clear output buffer
    ser0.write(msgPack)

    # read the switch status
    cmdPack = struct.pack(cmdStruct, Address, Command.GAP, 10, Motor5, 0)
    dataByte = bytearray(cmdPack)
    checksumInt = sum(dataByte[:]) % 256
    msgPack = struct.pack(msgStruct, Address, Command.GAP, 10, Motor5, 0, checksumInt)
    ser0.flushOutput() # Clear output buffer

    # check the switch status with an infinite write/read loop with two break out conditions
    while True: 
        QtGui.qApp.processEvents()  # 1. condition: interrupt with push button
        ser0.write(msgPack)
        reply = ser0.read(9)
        answer = struct.unpack('>BBBBlB', reply)
        value = answer[4]
        command = answer[3]
        if (command == 6) and (value == 1):     # 2. condition: interrupt with limit switch
            print 'end of line'
            Stop_Motor5()
            break

Answer 2

如果你的程序正在运行一个循环，你可以定期调用 processEvents，这样可以给图形界面留出时间来更新（这也能让你点击一个按钮来关闭应用程序）：

    count = 0
    while True:
         count += 1
         if not count % 50:
             QtGui.qApp.processEvents()
         # do stuff...