pyqt qlineedit 设置文字左对齐

在PyQt中，QLineEdit（线性编辑框）默认的文字布局是垂直居中。如果你想要设置文本左对齐，你需要自定义样式或者在创建`QLineEdit`时指定其` alignment `属性。以下是两种方法：

**方法一：通过样式表（StyleSheet）设置**

from PyQt5.QtWidgets import QApplication, QLineEdit, QLabel
from PyQt5.QtGui import QFontMetrics

app = QApplication([])

# 创建QLineEdit实例
lineEdit = QLineEdit()
lineEdit.setAlignment(Qt.AlignLeft)  # Qt.AlignLeft表示左对齐

# 使用样式表设置文本方向
font_metrics = QFontMetrics(lineEdit.font())
line_edit_width = font_metrics.horizontalAdvance('left aligned text') + 10  # 添加一些额外的空间
lineEdit.setFixedWidth(line_edit_width)

label = QLabel('左对齐文本')
label.setAlignment(Qt.AlignRight | Qt.AlignVCenter)  # 显示对比

widget_layout = QVBoxLayout()
widget_layout.addWidget(label)
widget_layout.addWidget(lineEdit)
main_window = QWidget()
main_window.setLayout(widget_layout)
main_window.show()

app.exec_()

**方法二：在构造函数中设置**

from PyQt5.QtWidgets import QApplication, QLineEdit

class CustomLineEdit(QLineEdit):
    def __init__(self):
        super().__init__()
        self.setAlignment(Qt.AlignLeft)

app = QApplication([])
custom_line_edit = CustomLineEdit()
custom_line_edit.show()

app.exec_()

在这两个例子中，