I played with PyQt5 and Python3

What is Qt?

Qt (Cute) is an application user interface (UI) framework written in the C ++ language.

Qt is widely known as a GUI toolkit, but it is also widely used in non-GUI programs such as console tools and servers. From Wikipedia

A framework that makes it easy to create GUI applications. It also supports cross-platform development.

What is PyQt?

PyQt is a cross-platform GUI toolkit, Qt's Python binding, and is one of the options for GUI programming in Python. From Wikipedia

You can easily create Qt and GUI applications set for Python.

Benefits of PyQt

• Rich in functions, you can intuitively create GUI applications.
• Qt supports not only Python but also various languages, so it is easy to port to other languages.

Problems with PyQt

• I'm not sure, but a license is required for commercial use (very expensive)
• Reference is difficult to read (probably my lack of reading comprehension, lack of English)

First, prepare an environment where you can use PyQt5

procedure

1. Install Python
2. Install Qt (may take a long time)
3. Install PyQt

I won't explain the environment settings here, so ggrks

Let's actually write the code

First, let's open the window

window.py

#!/usr/bin/env python3

import sys
from PyQt5.QtWidgets import *

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


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

    main_window.show()
    sys.exit(app.exec_())

When I run it, an empty window appears

Let's add a button and a title

button.py

#!/usr/bin/env python3

import sys
from PyQt5.QtWidgets import *

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

        button = QPushButton('button')

        layout = QGridLayout()
        layout.addWidget(button)
        self.setLayout(layout)
        self.setWindowTitle("Button")


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

    main_window.show()
    sys.exit(app.exec_())

With button and title

Let's read and display the value of the text field

input-output.py

#!/usr/bin/env python3

import sys
from PyQt5.QtWidgets import *

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

        self.button = QPushButton('Read / display')
        self.button.clicked.connect(self.output)
        self.inputText = QLineEdit()
        self.inputText.setText("")

        self.outputText = QLineEdit()
        self.outputText.setText("")
        self.outputText.setReadOnly(True)

        textLayout = QHBoxLayout()
        textLayout.addWidget(self.inputText)
        textLayout.addWidget(self.outputText)

        layout = QVBoxLayout()
        layout.addLayout(textLayout)
        layout.addWidget(self.button)
        self.setLayout(layout)
        self.setWindowTitle("Button")

    def output(self):
        self.outputText.setText(self.inputText.text())

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

    main_window.show()
    sys.exit(app.exec_())

When you enter text and press the button, the text is output

Display the character string entered in QGraphicsView

string-graphic.py

#!/usr/bin/env python3

import sys
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *


class ShowString(QGraphicsItem):
    def __init__(self, width=200, height=10, text=""):
        super(ShowString, self).__init__()
        self.width = width
        self.height = height
        self.text = text

    def paint(self, painter, option, widget):
        painter.setPen(Qt.black)
        painter.drawText(0, 20, self.text)

    def boundingRect(self):
        return QRectF(0,0,400,100)

    def setText(self, text):
        self.text = text
        self.update()

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

        self.graphicView = QGraphicsView()
        self.showString = ShowString()
        scene = QGraphicsScene(self.graphicView)
        scene.setSceneRect(0, 0, 400, 100)
        self.graphicView.setScene(scene)
        self.graphicView.resize(300,50)
        scene.addItem(self.showString)

        self.button = QPushButton('Read / display')
        self.button.clicked.connect(self.output)
        self.inputText = QLineEdit()
        self.inputText.setText("")

        self.outputText = QLineEdit()
        self.outputText.setText("")
        self.outputText.setReadOnly(True)

        textLayout = QHBoxLayout()
        textLayout.addWidget(self.inputText)
        textLayout.addWidget(self.outputText)

        layout = QVBoxLayout()
        layout.addWidget(self.graphicView)
        layout.addLayout(textLayout)
        layout.addWidget(self.button)
        self.setLayout(layout)
        self.setWindowTitle("Button")

    def output(self):
        self.outputText.setText(self.inputText.text())
        self.showString.setText(self.inputText.text())

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

    main_window.show()
    sys.exit(app.exec_())

Added character string output in QGraphicsView to the previous program

I may add a sample program again. .. ..

Continued: Try to open a subwindow with PyQt5 and Python

Impressions / Discussion

That's all for playing with PyQt5 and Python3. I like it because I can design GUIs really intuitively.

reference

I used it as a reference below. Thank you very much. http://d.hatena.ne.jp/mFumi/20141112/1415806010 http://qiita.com/kenasman/items/55505654823e9d040e6e