To change the text color to blue, you can use the setStyleSheet method:
def validate_input(): if len(line_edit.text()) < 5: line_edit.setStyleSheet("color: red;") else: line_edit.setStyleSheet("color: black;") line_edit.textChanged.connect(validate_input) Use code with caution. Troubleshooting Common Issues
For developers familiar with web design, Qt Style Sheets (QSS) offer a much more intuitive syntax. You can style widgets exactly how you style HTML elements. qlineedit text color
When the user highlights text, the default selection colors might clash with your new text color. You can control this via QSS as well:
# Error simulation self.error_input = QLineEdit() self.error_input.setPlaceholderText("Enter valid email...") self.error_input.textChanged.connect(self.validate_email) To change the text color to blue, you
When the line edit is disabled ( setEnabled(false) ), the text color naturally grays out, but you can control it:
def set_error_state(line_edit, is_error): if is_error: line_edit.setStyleSheet(""" QLineEdit color: #d32f2f; border: 1px solid #d32f2f; border-radius: 4px; background-color: #ffebee; You can control this via QSS as well:
Qt offers two primary engines for this: (CSS-like, powerful) and QPalette (system-aware, consistent).