TypeError：QFileDialog.history（self）：未绑定方法的第一个参数必须具有类型“ QFileDialog”

Question

I'm using PyQT and have already instantiated the class for my GUI. I'm trying to find the history of files opened in my GUI.

def plotButtonClicked(self):
    lst = QFileDialog.history(self)

The above def is called by another function which creates the whole GUI. I get the following error:

TypeError: QFileDialog.history(): first argument of unbound method must have type 'QFileDialog'

Funny thing is I've been using the QFileDialog in other functions. Here's one instance where it works:

fname = QFileDialog.getOpenFileName(self, 'Open File')

So why isn't the history() method not working?

Answer 1

QFileDialog.history is not a classmethod (also called static function in C++). For you to be able to call the method, you'd have to either pass the class as first argument (as the error says) or instantiate QFileDialog before calling the method.

The reason why QFileDialog.getOpenFileName works is because it's a classmethod (static method), and as the doc says, it's a convenience static function .