Sets the total amount for the main progress bar.
        
        :param      amount | <int>

def setTotal( self, amount ):
        """
        Sets the total amount for the main progress bar.
        
        :param      amount | <int>
        """
        self._primaryProgressBar.setValue(0)
        self._primaryProgressBar.setMaximum(amount)
        
        if amount:
            self.setCurrentMode(XLoaderWidget.Mode.Progress)