pyqt5 lineedit focusi事件怎么使用

可以使用以下代码实现：

from PyQt5.QtWidgets import QApplication, QLineEdit, QWidget

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

    def initUI(self):
        self.lineedit = QLineEdit(self)
        self.lineedit.move(20, 20)
        self.lineedit.resize(280, 40)
        self.lineedit.textChanged.connect(self.onTextChanged)
        self.lineedit.editingFinished.connect(self.onEditingFinished)

    def onTextChanged(self, text):
        print("Text changed:", text)

    def onEditingFinished(self):
        print("Editing finished")

    def focusInEvent(self, event):
        print("Focus in")

if __name__ == '__main__':
    app = QApplication([])
    widget = MyWidget()
    widget.show()
    app.exec_()

其中，`focusInEvent` 方法可以在 LineEdit 获得焦点时触发，可以在该方法中实现相应的逻辑。