QApplication が２度目に必ずエラーを吐く現象について from PySide import QtGui import sys class Widget(QtGui.QWidget): def __init__(self,parent=None): super(Widget,self).__init__(parent=None) def main(): try: QtGui.QApplication([]) except Exception as e: print(10,e) widget = Widget() widget.show() sys.exit(QtGui.QApplication.exec_()) if __name__ == "__main__": main() `Widget` `QApplication` `QApplication` `QApplication()` try:except A QApplication instance already exists. `RunTimeError` `Qt` Anaconda3 Spyder3.2.4

[[PySide] QtDesigner](

`A QApplication instance already exists.`


app = QtGui.QApplication(sys.argv)
# Error: A QApplication instance already exists.
# Traceback (most recent call last):
# File "", line 1, in
# RuntimeError: A QApplication instance already exists. #





app = QtGui.QApplication.instance()