(4) Pyqt5 tutorial -- > Custom signal and slot (super winding...)

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This column all source code GitHub Through train

In the last article, we talked about how to use the signals and slots that come with the object

This one is more winding , Anyway, I saw it for the first time , I feel dizzy . Let's be clear

Use the diagram below to make it clear

First of all, we need to know , who （ sender ） What signals are sent （ The signal ） To whom , Who receives the signal and performs what function （ Slot function ）

Code first

ui File code

# -*- coding: utf-8 -*-

# Form implementation generated from reading ui file '03.ui'
#
# Created by: PyQt5 UI code generator 5.15.2
#
# WARNING: Any manual changes made to this file will be lost when pyuic5 is
# run again. Do not edit this file unless you know what you are doing.


from PyQt5 import QtCore, QtGui, QtWidgets


class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(691, 509)
        self.verticalLayoutWidget = QtWidgets.QWidget(Form)
        self.verticalLayoutWidget.setGeometry(QtCore.QRect(100, 60, 391, 231))
        self.verticalLayoutWidget.setObjectName("verticalLayoutWidget")
        self.verticalLayout = QtWidgets.QVBoxLayout(self.verticalLayoutWidget)
        self.verticalLayout.setContentsMargins(0, 0, 0, 0)
        self.verticalLayout.setObjectName("verticalLayout")
        self.pushButton_2 = QtWidgets.QPushButton(self.verticalLayoutWidget)
        self.pushButton_2.setObjectName("pushButton_2")
        self.verticalLayout.addWidget(self.pushButton_2)
        self.pushButton_3 = QtWidgets.QPushButton(self.verticalLayoutWidget)
        self.pushButton_3.setObjectName("pushButton_3")
        self.verticalLayout.addWidget(self.pushButton_3)
        self.pushButton_4 = QtWidgets.QPushButton(self.verticalLayoutWidget)
        self.pushButton_4.setObjectName("pushButton_4")
        self.verticalLayout.addWidget(self.pushButton_4)
        self.pushButton_1 = QtWidgets.QPushButton(self.verticalLayoutWidget)
        self.pushButton_1.setObjectName("pushButton_1")
        self.verticalLayout.addWidget(self.pushButton_1)
        self.pushButton_5 = QtWidgets.QPushButton(self.verticalLayoutWidget)
        self.pushButton_5.setObjectName("pushButton_5")
        self.verticalLayout.addWidget(self.pushButton_5)
        self.label = QtWidgets.QLabel(Form)
        self.label.setGeometry(QtCore.QRect(140, 340, 411, 81))
        font = QtGui.QFont()
        font.setFamily("Agency FB")
        font.setPointSize(14)
        self.label.setFont(font)
        self.label.setObjectName("label")

        self.retranslateUi(Form)
        QtCore.QMetaObject.connectSlotsByName(Form)

    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.pushButton_1.setText(_translate("Form", " No parameter "))
        self.pushButton_2.setText(_translate("Form", " One int Type parameter "))
        self.pushButton_3.setText(_translate("Form", "int and str There are two parameters of type "))
        self.pushButton_4.setText(_translate("Form", " List as parameter "))
        self.pushButton_5.setText(_translate("Form", " Dictionaries as parameters "))
        self.label.setText(_translate("Form", " Custom signal and slot tests , And parameter passing "))

Master file code ：

from ui3 import Ui_Form
import sys,time
from PyQt5 import QtWidgets,QtCore


class mydesigner(QtWidgets.QWidget,Ui_Form):
    # Define custom signals 
    signal_1 = QtCore.pyqtSignal()# With no arguments 

    signal_2 = QtCore.pyqtSignal(int)# belt int Type parameter 

    signal_3 = QtCore.pyqtSignal(int,str)# belt int and str Two parameters 

    signal_4 = QtCore.pyqtSignal(list)# With list type 

    signal_5 = QtCore.pyqtSignal(dict)# Typical with character 

    def __init__(self):
        super(mydesigner,self).__init__()
        self.setupUi(self)

        # Bind custom functions for custom signals , When the receiver receives this signal , This function will be executed 
        self.signal_1.connect(self.signal_1_response)
        self.signal_2.connect(self.signal_2_response)
        self.signal_3.connect(self.signal_3_response)
        self.signal_4.connect(self.signal_4_response)
        self.signal_5.connect(self.signal_5_response)
        
        self.pushButton_1.clicked.connect(self.signal_1_call)
        self.pushButton_2.clicked.connect(self.signal_2_call)
        self.pushButton_3.clicked.connect(self.signal_3_call)
        self.pushButton_4.clicked.connect(self.signal_4_call)
        self.pushButton_5.clicked.connect(self.signal_5_call)
        
    def signal_1_call(self):
        self.signal_1.emit()

    def signal_2_call(self):
        self.signal_2.emit(1)

    def signal_3_call(self):
        self.signal_3.emit(1,"test")

    def signal_4_call(self):
        self.signal_4.emit([1,2,3,4])

    def signal_5_call(self):
        self.signal_5.emit({
    "name":"huhaoming","age":"20"})

    # Custom slot function 
    def signal_1_response(self):
        print(" With no arguments ")
    def signal_2_response(self,val):
        print(" With shaping parameters ：",val)
        
    def signal_3_response(self,val_int,val_str):
        print(" belt int and str Two parameters :",val_int,val_str)
    def signal_4_response(self,val):
        print(" With list type ：",val)
    def signal_5_response(self,val):
        print(" Typical with character ：",val)

  
if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    myshow = mydesigner()
    myshow.show()
    sys.exit(app.exec_())

In order to express myself better, I understand , I'll use the following diagram with the code ：

Just understand two lines of code

First of all ：

self.pushButton_1.clicked.connect(self.signal_1_call)

This means the main interface Of Button Of Click event Connect the self.signal_1_call This function , To put it another way, when this button clicks （ Not limited to clicking , There could be other events ） I will go to perform self.signal_1_call This function , And this function is responsible for transmitting a custom signal . Here is the launch to the main interface .

second ：

 self.signal_1.connect(self.signal_1_response)

This means that the signal on the main interface is connected to self.signal_1_response This function , When the main interface receives this signal , Go back to execution ,self.signal It's a property of the main interface , A signal can be specified to connect a slot function , This slot function is when you transmit this signal , What you want me to do . This slot function can print out the parameters directly . It's reflected in the code

Anyway, it's very winding here , I don't know how you guys learn . It's much better to understand （ For obsessive-compulsive disorder ）.

**

This code can be run directly . There's another point I forgot to say , When defining a custom signal, you need to use pyqtSignal class , So a signal can also be regarded as an object ,pyqtSignal Class in QtCore under . Import required

**

For the signal and slot function of the user-defined and its transfer parameters when temporarily learning and understanding here , There may be mistakes in this blog , For reference only . I'll come back later when I understand better .

This source code is also uploaded to gitHub The above , Connect to the top of the blog .