View Exercise 1 Solution

main.py

from qtpy import QtWidgets

import sys

import view

"""
A wrapper class for setting the main window
"""
class Demo(QtWidgets.QMainWindow):
    def __init__(self,parent=None):
        super().__init__(parent)

        self.window = QtWidgets.QMainWindow()
        my_view = view.View()

        # set the view for the main window
        self.setCentralWidget(my_view)
        self.setWindowTitle("view tutorial")

def get_qapplication_instance():
    if QtWidgets.QApplication.instance():
        app = QtWidgets.QApplication.instance()
    else:
        app = QtWidgets.QApplication(sys.argv)
    return app

app = get_qapplication_instance()
window = Demo()
window.show()
app.exec_()

view.py

from qtpy import QtWidgets, QtCore, QtGui


class View(QtWidgets.QWidget):

    def __init__(self, parent=None):
        super().__init__(parent)

        grid = QtWidgets.QVBoxLayout(self)

        self.table = QtWidgets.QTableWidget(self)
        self.table.setRowCount(4)
        self.table.setColumnCount(2)
        grid.addWidget(self.table)

        self.colours = QtWidgets.QComboBox()
        options = ["Blue", "Green", "Red"]
        self.colours.addItems(options)

        self.grid_lines = QtWidgets.QTableWidgetItem()
        self.grid_lines.setFlags(QtCore.Qt.ItemIsUserCheckable | QtCore.Qt.ItemIsEnabled)
        self.grid_lines.setCheckState(QtCore.Qt.Unchecked)
        self.addItemToTable("Show grid lines", self.grid_lines, 1)

        self.freq = QtWidgets.QTableWidgetItem("1.0")
        self.phi = QtWidgets.QTableWidgetItem("0.0")

        self.addWidgetToTable("Colour", self.colours, 0)
        self.addItemToTable("Frequency", self.freq, 2)
        self.addItemToTable("Phase", self.phi, 3)

        self.plot = QtWidgets.QPushButton('Add', self)
        self.plot.setStyleSheet("background-color:lightgrey")

        grid.addWidget(self.plot)

        self.setLayout(grid)

    def setTableRow(self, name, row):
        text = QtWidgets.QTableWidgetItem(name)
        text.setFlags(QtCore.Qt.ItemIsEnabled)
        col = 0
        self.table.setItem(row, col, text)

    def addWidgetToTable(self, name, widget, row):
        self.setTableRow(name,row)
        col = 1
        self.table.setCellWidget(row, col, widget)

    def addItemToTable(self, name, widget, row):
        self.setTableRow(name, row)
        col = 1
        self.table.setItem(row, col, widget)

In the above code the following functions have been added to prevent repetition of code:

• setTableRow sets the label for the table row

• addWidgetToTable adds a widget to the table

• addItemToTable adds an item to the table (needed because the frequency and phase are items and not widgets)