Various controls ==pyqt5

QCheckBox

• QCheckBox Check box control , It has two states ： Open and close , It is a tag with text Label Control for
• Checkboxes are often used to indicate features that a program can enable or disable

import sys
from PyQt5.QtWidgets import QWidget, QCheckBox, QApplication
from PyQt5.QtCore import Qt

class Example(QWidget):
    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):

        cb = QCheckBox('Show title', self)# label 
        cb.move(20, 20)
        # We have set the window title , So we must also check the check box . By default , No window title is set and no check box is checked .
        cb.toggle()
        # We're going to customize changeTitle() Method to connect to stateChanged The signal . This method will switch the title of the form .
        cb.stateChanged.connect(self.changeTitle)#signal

        # Interface Qwidget
        self.setGeometry(300, 300, 250, 150)
        self.setWindowTitle('QCheckBox')
        self.show()

    # The status of the check box is via state Parameters of the incoming changeTitle() Method . Set the title of the form when the check box is checked , When unchecked, the title will be set as an empty string .
    def changeTitle(self, state):#slot

        if state == Qt.Checked:
            self.setWindowTitle('QCheckBox')
        else:
            self.setWindowTitle('')

Switch button Toggle button

• ToggleButton yes QPushButton It's a special pattern of . It is a button with two states ： Pressed and not pressed . Switch back and forth between these two states by clicking . This feature can be useful in some scenarios .

import sys
from PyQt5.QtWidgets import (QWidget, QPushButton,
                             QFrame, QApplication)
from PyQt5.QtGui import QColor


class Example1(QWidget):

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

        self.initUI()

    def initUI(self):
        self.col = QColor(0, 0, 0)# This is the value of the initial black color .

        # We create a QPushButton And through its setCheckable() Method to get one ToggleButton.
        redb = QPushButton('Red', self)
        redb.setCheckable(True)
        redb.move(10, 10)
        # take clicked The signal is connected to a user-defined method . We go through clicked The signal operates on a Boolean value .
        redb.clicked[bool].connect(self.setColor)

        greenb = QPushButton('Green', self)
        greenb.setCheckable(True)
        greenb.move(10, 60)
        greenb.clicked[bool].connect(self.setColor)

        blueb = QPushButton('Blue', self)
        blueb.setCheckable(True)
        blueb.move(10, 110)
        blueb.clicked[bool].connect(self.setColor)

        self.square = QFrame(self)
        self.square.setGeometry(150, 20, 100, 100)
        self.square.setStyleSheet("QWidget { background-color: %s }" %
                                  self.col.name())

        self.setGeometry(300, 300, 280, 170)
        self.setWindowTitle('Toggle button')
        self.show()

    def setColor(self, pressed):
        source = self.sender()

        if pressed:
            val = 255
        else:
            val = 0

        if source.text() == "Red":
            self.col.setRed(val)
        elif source.text() == "Green":
            self.col.setGreen(val)
        else:
            self.col.setBlue(val)

        self.square.setStyleSheet("QFrame { background-color: %s }" %
                                  self.col.name())

Slider bar QSlider

• QSlider Is a control with a simple slider . The slider can be dragged back and forth . We can select a specific value by dragging . Sometimes it's more natural to use a slider than to enter a number directly or use a spin box .
• We will display a slider and a tab , Labels are used to display pictures , And through the slide bar control picture display
• Note that the picture here can only be used ico Format ,png Format pictures will not be displayed .

import sys
from PyQt5.QtWidgets import (QWidget, QSlider,
                             QLabel, QApplication)
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QPixmap

class Example2(QWidget):
    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        sld = QSlider(Qt.Horizontal, self)# Create a horizontal slider 
        sld.setFocusPolicy(Qt.NoFocus)
        sld.setGeometry(30, 40, 100, 30)
        sld.valueChanged[int].connect(self.changeValue)# We will valueChanged The signal is connected to a custom changeValue() Method .

        self.label = QLabel(self)# Created a QLabel Control and set an initial volume image for it .
        self.label.setPixmap(QPixmap('audio.ico'))
        self.label.setGeometry(160, 40, 80, 30)

        self.setGeometry(300, 300, 280, 170)
        self.setWindowTitle('QSlider')
        self.show()

    def changeValue(self, value):
        if value == 0:
            self.label.setPixmap(QPixmap('audio.ico'))
        elif value > 0 and value <= 30:
            self.label.setPixmap(QPixmap('min.ico'))
        elif value > 30 and value < 80:
            self.label.setPixmap(QPixmap('med.ico'))
        else:
            self.label.setPixmap(QPixmap('max.ico'))

Progress bar QProgressBar

• A progress bar is a control that shows the progress of a task .QProgressBar Control provides a horizontal or vertical PyQt5 Progress bar of tool kit .
• The creator can set the minimum and maximum values of the progress bar. The default is 0-99

import sys
from PyQt5.QtWidgets import (QWidget, QProgressBar,
                             QPushButton, QApplication)
from PyQt5.QtCore import QBasicTimer

class Example3(QWidget):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.pbar = QProgressBar(self)#QProgressBar Construction method of 
        self.pbar.setGeometry(30, 40, 200, 25)

        self.btn = QPushButton('Start', self)
        self.btn.move(40, 80)
        self.btn.clicked.connect(self.doAction)

        self.timer = QBasicTimer()# We use a timer timer To activate QProgressBar
        self.step = 0

        self.setGeometry(300, 300, 280, 170)
        self.setWindowTitle('QProgressBar')
        self.show()
    # Every QObject And its subclasses have a timerEvent() Event handler . We will re implement the event handler to respond to timer events .
    def timerEvent(self, e):
        if self.step >= 100:
            self.timer.stop()
            self.btn.setText('Finished')
            return

        self.step = self.step + 1
        self.pbar.setValue(self.step)

    def doAction(self):
        if self.timer.isActive():
            self.timer.stop()
            self.btn.setText('Start')
        else:# We call start() Method to start a timer . This method has two parameters : Timeouts and events that the object will receive .
            self.timer.start(100, self)
            self.btn.setText('Stop')

calendar control QCalendarWidget

• QCalendarWidget Provides a calendar control based on month . It allows users to select dates in a simple and intuitive way .
• Created a calendar control and a label control . The selected date will be displayed in the label control .

import sys
from PyQt5.QtWidgets import (QWidget, QCalendarWidget,
                             QLabel, QApplication)
from PyQt5.QtCore import QDate

class Example4(QWidget):
    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        cal = QCalendarWidget(self)#QCalendarWidget Be created 
        cal.setGridVisible(True)
        cal.move(20, 20)
        cal.clicked[QDate].connect(self.showDate)# If we choose a date from the part , Click on [QDate] Signal . We connect this signal to a user-defined showDate() Method .

        self.lbl = QLabel(self)
        date = cal.selectedDate()
        self.lbl.setText(date.toString())
        self.lbl.move(130, 260)

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

    def showDate(self, date):
        self.lbl.setText(date.toString())

Qpixmap

• QPixmap Is a control for processing images . Is the optimized display image on the screen .
• In our code example , We will use QPixmap The window displays an image

import sys
from PyQt5.QtWidgets import (QWidget, QHBoxLayout,
                             QLabel, QApplication)
from PyQt5.QtGui import QPixmap


class Example5(QWidget):
    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        hbox = QHBoxLayout(self)
        pixmap = QPixmap("../essential_fuction_2/camera.png")# Creating a QPixmap  object , It takes the passed in file name as a parameter .

        lbl = QLabel(self)
        lbl.setPixmap(pixmap)# This will make us pixmap Put it in QLabel Control .

        hbox.addWidget(lbl)# Horizontal layout 
        self.setLayout(hbox)

        self.move(300, 200)
        self.setWindowTitle('Red Rock')
        self.show()

The text box QLineEdit

• QLineEdit Is a control for entering or editing single line text . It also has undo redo 、 Cut, copy and drag .

import sys
from PyQt5.QtWidgets import (QWidget, QLabel,
                             QLineEdit, QApplication)

class Example6(QWidget):
    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        self.lbl = QLabel(self)
        qle = QLineEdit(self)

        qle.move(60, 100)
        self.lbl.move(60, 40)

        qle.textChanged[str].connect(self.onChanged)# When the content of the text box changes , Would call onChanged Method 

        self.setGeometry(300, 300, 280, 170)
        self.setWindowTitle('QLineEdit')
        self.show()

    # take QLabel Control to the input . By calling adjustSize() Methods will QLabel Control is resized to the length of the text .
    def onChanged(self, text):
        self.lbl.setText(text)
        self.lbl.adjustSize()

QSplitter

• adopt QSplitter, The user can drag the border of the child control to adjust the size of the child control .
• In the following example , We show three by two QSplitter The organization's QFrame Control .
• Created three QFrame With two QSplitter. Note these in some topics QSplitter May not be visible .

import sys
from PyQt5.QtWidgets import (QWidget, QHBoxLayout, QFrame,
                             QSplitter, QStyleFactory, QApplication)
from PyQt5.QtCore import Qt

class Example7(QWidget):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        hbox = QHBoxLayout(self)

        # We use a style framework in order to see QFrame Boundaries between widgets .
        topleft = QFrame(self)#
        topleft.setFrameShape(QFrame.StyledPanel)

        topright = QFrame(self)
        topright.setFrameShape(QFrame.StyledPanel)

        bottom = QFrame(self)
        bottom.setFrameShape(QFrame.StyledPanel)

        # We create a QSplitter Widget and add two frames .
        splitter1 = QSplitter(Qt.Horizontal)
        splitter1.addWidget(topleft)
        splitter1.addWidget(topright)

        # We can also put QSplitter Add to another QSplitter Control .
        splitter2 = QSplitter(Qt.Vertical)
        splitter2.addWidget(splitter1)
        splitter2.addWidget(bottom)

        hbox.addWidget(splitter2)
        self.setLayout(hbox)

        self.setGeometry(300, 300, 300, 200)
        self.setWindowTitle('QSplitter')
        self.show()

    def onChanged(self, text):
        self.lbl.setText(text)
        self.lbl.adjustSize()

The drop-down list QComboBox

• QComboBox Is a control that allows the user to select from a drop-down list .

import sys
from PyQt5.QtWidgets import (QWidget, QLabel,
                             QComboBox, QApplication)


class Example8(QWidget):
    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        self.lbl = QLabel("Ubuntu", self)

        combo = QComboBox(self)# Created a with five options QComboBox
        combo.addItem("Ubuntu")
        combo.addItem("Mandriva")
        combo.addItem("Fedora")
        combo.addItem("Arch")
        combo.addItem("Gentoo")

        combo.move(50, 50)
        self.lbl.move(50, 150)

        combo.activated[str].connect(self.onActivated)# When an entry is selected, it calls onActivated() Method .

        self.setGeometry(300, 300, 300, 200)
        self.setWindowTitle('QComboBox')
        self.show()

    def onActivated(self, text):# In the method we will QLabel The content of the control is set to the selected item , Then adjust its size .
        self.lbl.setText(text)
        self.lbl.adjustSize()

if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example8()
    sys.exit(app.exec_())

Message_box

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

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

        self.initUI()

    def initUI(self):

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

    def closeEvent(self, event):# When we close the window , Triggered QCloseEvent. We need to rewrite closeEvent() Event handler .

        reply = QMessageBox.question(self, 'Message',
                                     "Are you sure to quit?", QMessageBox.Yes |
                                     QMessageBox.No, QMessageBox.No)

        if reply == QMessageBox.Yes:
            event.accept()
        else:
            event.ignore()


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