# Only needed for access to command line arguments
import sys

from PyQt5.QtGui import QPalette, QColor
from PyQt5.QtWidgets import QMainWindow, QGridLayout, QWidget, QApplication


# 自定义窗口，继承 QMainWindow
def index_changed(s):
    print(s)


class MainWindow(QMainWindow):

    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)
        self.setWindowTitle("My Awesome App")  # 标题

        layout = QGridLayout()
        layout.addWidget(Color('red'), 0, 0)
        layout.addWidget(Color('green'), 0, 1)
        layout.addWidget(Color('blue'), 1, 0)
        layout.addWidget(Color('purple'), 1, 1)

        widget = QWidget()
        widget.setLayout(layout)
        self.setCentralWidget(widget)


class Color(QWidget):

    def __init__(self, color, *args, **kwargs):
        super(Color, self).__init__(*args, **kwargs)
        self.setAutoFillBackground(True)

        palette = self.palette()
        palette.setColor(QPalette.Window, QColor(color))
        self.setPalette(palette)


if __name__ == '__main__':
    app = QApplication(sys.argv)

    window = MainWindow()
    window.show()  # 默认下 windows 是隐藏的
    # 开启事件循环
    app.exec_()