PyQt：点击事件清除QLineEdit

Question

我对Python和Qt Designer非常新颖。使用给定的代码，我希望用户在QLineEdit小部件中输入文本，按下Copy！按钮并看到输入的文本替换'N/A'标签。我的问题是：按照这个程序，我怎样才能通过简单的鼠标点击清除QLineEdit小部件中输入的文本？

从我读到的（this,this和this）看来我需要在扩展QLineEdit的新类中重新实现focusInEvent（）。我的问题是我的GUI的代码已经使用pyuic5从Qt Designer导入，上面引用的例子似乎没有考虑到这一点。

这里是我的代码：

from PyQt5.QtWidgets import * 
import sys 

import QLineEdit_test 


class MainWindow(QMainWindow, QLineEdit_test.Ui_QLineEdit_test): 

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

     self.copy_button.clicked.connect(self.copy_and_print) 

    def copy_and_print(self): 

     self.label.setText(self.lineEdit.text()) 


def main(): 

    app = QApplication(sys.argv) 
    form = MainWindow() 
    form.show() 
    app.exec_() 

if __name__ == "__main__": 
    main() 

这是我转换的.ui文件：

from PyQt5 import QtCore, QtGui, QtWidgets 

class Ui_QLineEdit_test(object): 
    def setupUi(self, QLineEdit_test): 
     QLineEdit_test.setObjectName("QLineEdit_test") 
     QLineEdit_test.resize(300, 200) 
     QLineEdit_test.setMaximumSize(QtCore.QSize(300, 200)) 
     self.centralwidget = QtWidgets.QWidget(QLineEdit_test) 
     self.centralwidget.setObjectName("centralwidget") 
     self.gridLayout_2 = QtWidgets.QGridLayout(self.centralwidget) 
     self.gridLayout_2.setObjectName("gridLayout_2") 
     self.gridLayout = QtWidgets.QGridLayout() 
     self.gridLayout.setObjectName("gridLayout") 
     self.lineEdit = QtWidgets.QLineEdit(self.centralwidget) 
     self.lineEdit.setMaximumSize(QtCore.QSize(120, 16777215)) 
     self.lineEdit.setObjectName("lineEdit") 
     self.gridLayout.addWidget(self.lineEdit, 0, 0, 1, 1) 
     self.copy_button = QtWidgets.QPushButton(self.centralwidget) 
     self.copy_button.setObjectName("copy_button") 
     self.gridLayout.addWidget(self.copy_button, 1, 0, 1, 1) 
     self.label = QtWidgets.QLabel(self.centralwidget) 
     self.label.setMaximumSize(QtCore.QSize(200, 20)) 
     self.label.setAlignment(QtCore.Qt.AlignCenter) 
     self.label.setObjectName("label") 
     self.gridLayout.addWidget(self.label, 2, 0, 1, 1) 
     self.gridLayout_2.addLayout(self.gridLayout, 0, 0, 1, 1) 
     QLineEdit_test.setCentralWidget(self.centralwidget) 
     self.menubar = QtWidgets.QMenuBar(QLineEdit_test) 
     self.menubar.setGeometry(QtCore.QRect(0, 0, 300, 22)) 
     self.menubar.setObjectName("menubar") 
     QLineEdit_test.setMenuBar(self.menubar) 
     self.statusbar = QtWidgets.QStatusBar(QLineEdit_test) 
     self.statusbar.setObjectName("statusbar") 
     QLineEdit_test.setStatusBar(self.statusbar) 

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

    def retranslateUi(self, QLineEdit_test): 
     _translate = QtCore.QCoreApplication.translate 
     QLineEdit_test.setWindowTitle(_translate("QLineEdit_test", "MainWindow")) 
     self.copy_button.setText(_translate("QLineEdit_test", "Copy!")) 
     self.copy_button.setShortcut(_translate("QLineEdit_test", "Return")) 
     self.label.setText(_translate("QLineEdit_test", "N/A")) 

谢谢！

Answer 1

解决方案是促进QtDesigner使用我们的自定义QLineEdit，我们在mousePressEvent的帮助下实施信号点击，这个类将被称为ClickableLineEdit，该文件将被称为ClickableLineEdit.py。

ClickableLineEdit.py

from PyQt5.QtCore import pyqtSignal 
from PyQt5.QtWidgets import QLineEdit 


class ClickableLineEdit(QLineEdit): 
    clicked = pyqtSignal() 
    def mousePressEvent(self, event): 
     self.clicked.emit() 
     QLineEdit.mousePressEvent(self, event) 

要推动它，以下结构将被视为：

. 
├── ClickableLineEdit.py 
├── main.py 
├── your.ui 
└── QLineEdit_test.py 

开放式设计使用Qt Designer和右键点击QLineEdit的选择Promote to ...：

菜单将打开，把下面的

然后按和推广。然后我们再次生成代码。

然后我们连接信号明确：

class MainWindow(QMainWindow, QLineEdit_test.Ui_QLineEdit_test): 

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

     self.copy_button.clicked.connect(self.copy_and_print) 
     self.lineEdit.clicked.connect(self.lineEdit.clear) 

    def copy_and_print(self): 
     self.label.setText(self.lineEdit.text())