PyQt + Matplotlib

[frohr]

Thank you, I have made great progress.

I have inactive button as value indicator (I just like the style).
I defined button in buttonbox2:

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)
        self.canvas = MplCanvas(self, width=5, height=4, dpi=100)
        self.setCentralWidget(self.canvas)
        self.setMinimumSize(1024,600)   
        toolbar = NavigationToolbar(self.canvas, self)
        layout = QtWidgets.QVBoxLayout()
        buttonbox = QHBoxLayout()
        buttonbox2 = QHBoxLayout()

        btn7 = QPushButton("mm/s: 10.1")
        btn7.setEnabled(False)
        buttonbox2.addWidget(btn7)

Then I want change button text to peak value:

    def time_signal(self):
        serial_read()
        self.ydata = time_data
        self.canvas.axes.cla()  
        self.canvas.axes.plot(self.ydata[0:500], 'b')
        self.canvas.draw()

        btn7.settext(str(max(g_data)))   #----------------------------------------------------------
     

Is there any way how to change button text? I tried self.btn7, etc. etc. but no success.
Thank you