如果用户选择了错误的文件类型，如何显示错误消息？

Question

我分配了一个项目，其中一部分是让用户选择一些文件或文件夹。我的代码工作正常。如果用户选择了错误的文件类型，我想要做的是引发错误消息。当他/她单击某个按钮时，用户应该访问某种类型的文件，即如果他单击“选择 Java 文件/文件夹”按钮，那么他/她将只选择 Java 文件。请指导。我的代码如下，用于选择文件和文件夹。我还需要补充什么？

def Select_File(self):
    root = Tk()
    root.withdraw()
    self.filename = filedialog.askopenfilenames(initialdir='/', title='Select a File', 
                                               filetype=(('Java','*.java'),('C#','*.cs'),('C++','*.cpp')))
    if self.filename:
        self.scanner = FileScanner()
        self.data = self.scanner.Project_Scanner(self.filename)
        self.Display(self.data)
    else:
        self.msg.setText("No File Selected")
        self.msg.setInformativeText('Please Select a File to Proceed')
        self.msg.setWindowTitle("Error")
        self.msg.exec_()
 

def Select_Project(self):
    root = Tk()
    root.withdraw()
    self.folder_selected = filedialog.askdirectory(initialdir='/', title='Select Folder')
    if self.folder_selected:
        self.files = self.get_Files(self.folder_selected)
        self.scanner = FileScanner()
        self.data = self.scanner.Project_Scanner(self.files)
        self.Display(self.data)
    else:
        self.msg.setText("No Folder Selected")
        self.msg.setInformativeText('Please Select a Folder to Proceed')
        self.msg.setWindowTitle("Error")
        self.msg.exec_()
 

Answer 1

尝试删除其他文件类型并检查文件名是否为 java 文件：

from tkinter.messagebox import showerror

def Select_File(self):
    root = Tk()
    root.withdraw()
    self.filename = filedialog.askopenfilenames(initialdir='/', title='Select a File', 
                                               filetype=(('Java','*.java'),))
    if self.filename:
        try:
            assert self.filename.split('.')[-1] == 'java'
            self.scanner = FileScanner()
            self.data = self.scanner.Project_Scanner(self.filename)
            self.Display(self.data)
        except Exception as e:
            print(e, type(e))
            showerror("File Open", "had an issue opening file")
    else:
        self.msg.setText("No File Selected")
        self.msg.setInformativeText('Please Select a File to Proceed')
        self.msg.setWindowTitle("Error")
        self.msg.exec_()```