Layout management ==pyqt5

Box layout Boxlayout

• We use QHBoxLayout and QVBoxLayout, To create horizontal layout and vertical layout respectively .

import sys
from PyQt5.QtWidgets import (QWidget, QPushButton,
                             QHBoxLayout, QVBoxLayout, QApplication)

class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        okButton = QPushButton("OK")
        cancelButton = QPushButton("Cancel")

        hbox = QHBoxLayout()
        hbox.addStretch(1)
        hbox.addWidget(okButton)
        hbox.addWidget(cancelButton)

        vbox = QVBoxLayout()
        vbox.addStretch(1)# stretch factor 
        vbox.addLayout(hbox)

        self.setLayout(vbox)

        self.setGeometry(300, 300, 300, 150)
        self.setWindowTitle('Buttons')
        self.show()

if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

Table layout

• Divide the space into rows and columns . We use QGridLayout Class to create a grid layout .

import sys
from PyQt5.QtWidgets import (QWidget, QGridLayout,
                             QPushButton, QApplication)


class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):

        grid = QGridLayout()
        self.setLayout(grid)# Let's create a grid button .

        names = ['Cls', 'Bck', '', 'Close',# These button labels 
                 '7', '8', '9', '/',
                 '4', '5', '6', '*',
                 '1', '2', '3', '-',
                 '0', '.', '=', '+']

        positions = [(i, j) for i in range(5) for j in range(4)]

        for position, name in zip(positions, names):# We create a list of locations in the grid 

            if name == '':
                continue
            button = QPushButton(name)
            grid.addWidget(button, *position)

        self.move(300, 150)
        self.setWindowTitle('Calculator')
        self.show()
        
# Control can span multiple rows and columns in the grid 
import sys
from PyQt5.QtWidgets import (QWidget, QLabel, QLineEdit,
                             QTextEdit, QGridLayout, QApplication)

class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        title = QLabel('Title')# Label text 
        author = QLabel('Author')
        review = QLabel('Review')

        titleEdit = QLineEdit()# Text editing Office 
        authorEdit = QLineEdit()
        reviewEdit = QTextEdit()

        grid = QGridLayout()# Table layout 
        grid.setSpacing(10)

        grid.addWidget(title, 1, 0)
        grid.addWidget(titleEdit, 1, 1)# Create a grid layout and set the spacing between components .

        grid.addWidget(author, 2, 0)
        grid.addWidget(authorEdit, 2, 1)

        grid.addWidget(review, 3, 0)
        grid.addWidget(reviewEdit, 3, 1, 5, 1)

        self.setLayout(grid)

        self.setGeometry(300, 300, 350, 300)
        self.setWindowTitle('Review')
        self.show()


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

Absolute positioning

• The program specifies the location and size of each control ( In pixels )
• Absolute positioning has the following limitations ：
  - If we adjust the window , The size and position of the control will not change
  - Applications will look different on various platforms
  - If you change the font , The layout of our application will change
  - If we decide to change our layout , We have to completely redo our layout

import sys
from PyQt5.QtWidgets import QWidget, QLabel, QApplication
class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        lbl1 = QLabel('Zetcode', self)
        lbl1.move(15, 10)# We use move() Method to control the position of the control 

        lbl2 = QLabel('tutorials', self)
        lbl2.move(35, 40)

        lbl3 = QLabel('for programmers', self)
        lbl3.move(55, 70)

        self.setGeometry(300, 300, 250, 150)
        self.setWindowTitle('Absolute')
        self.show()


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())