Python：如果QlineEdit已填充，如何启用按钮

Question

有人可以告诉我什么方法或什么逻辑，所以如果所有字段都不为空，QPush按钮将被启用。我正在创建一个简单的表单，如果字段不为空，则只能按下按钮。

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(392, 232)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.lineEdit = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit.setGeometry(QtCore.QRect(140, 60, 113, 20))
        self.lineEdit.setObjectName("lineEdit")
        self.lineEdit_2 = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit_2.setGeometry(QtCore.QRect(140, 90, 113, 20))
        self.lineEdit_2.setObjectName("lineEdit_2")
        self.label = QtWidgets.QLabel(self.centralwidget)
        self.label.setGeometry(QtCore.QRect(100, 60, 47, 13))
        self.label.setObjectName("label")
        self.label_2 = QtWidgets.QLabel(self.centralwidget)
        self.label_2.setGeometry(QtCore.QRect(100, 90, 47, 13))
        self.label_2.setObjectName("label_2")
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setEnabled(False)
        self.pushButton.setGeometry(QtCore.QRect(300, 170, 75, 23))
        self.pushButton.setObjectName("pushButton")
        MainWindow.setCentralWidget(self.centralwidget)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

这是一个示例代码。

Answer 1

您必须将textChanged信号连接到一个插槽，您可以在其中验证启用或禁用按钮所需的条件：

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        # ...

class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.setupUi(self)
        self.lineEdit.textChanged.connect(self.on_text_changed)
        self.lineEdit_2.textChanged.connect(self.on_text_changed)

    @QtCore.pyqtSlot()
    def on_text_changed(self):
        self.pushButton.setEnabled(bool(self.lineEdit.text()) and bool(self.lineEdit_2.text()))

if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())