JavaFX FileChooser Filefilter不返回扩展名 [英] JavaFX FileChooser Filefilter not returning extension

问题描述

在我的项目中，我使用JavaFX FileChooser来让用户保存文件.我注意到了一个错误，即带有指定文件过滤器的文件在Linux系统上总是保存为.txt.与Windows不同，我从另一个stackoverflow线程中了解到，在Linux上，fileChooser.showSaveDialog();返回一个没有所选文件扩展名的文件.我相信，这种不定期的实施有一个非常明显的原因，我不理解.但是我仍然不确定如何适应我的需求.

In my project I use JavaFX FileChooser to let the user save files. I noticed a bug, where a file with a specified file filter would always save as a .txt on Linux systems. From another stackoverflow thread I leaned that unlike Windows, on Linux the fileChooser.showSaveDialog(); returns a file without the chosen file extension. I am confident, that this irregular implementation has a very obvious cause that I am not understanding. But still I am not sure how to adapt this for my needs.

我知道关于类似主题还有其他一些已解决的主题，但是所有解决方案都基于从返回的文件中提取扩展名，在我的情况下，showSaveDialog没有返回扩展名.

I am aware that there are some other solved threads about a similar topic, but all the solutions are based on extracting the extension from the returned file, where in my case there is no extension returned by showSaveDialog.

推荐答案

下面是一个示例，如果用户未使用所选过滤器键入扩展名，则会添加扩展名:

Here is an example that adds an extension if the user didn't type one using their selected filter:

@Override
public void start(Stage primaryStage) {
    Button btn = new Button();
    btn.setText("Save to file.");
    btn.setOnAction(new EventHandler<ActionEvent>() {

        @Override
        public void handle(ActionEvent event) {
            FileChooser fc = new FileChooser();
            FileChooser.ExtensionFilter xmlfilter = new FileChooser.ExtensionFilter("XML", "*.xml");
            FileChooser.ExtensionFilter mffilter = new FileChooser.ExtensionFilter("mf", "*.mf");
            fc.getExtensionFilters().addAll(xmlfilter,mffilter);
            fc.setSelectedExtensionFilter(xmlfilter);
            File f = fc.showSaveDialog(primaryStage.getOwner());
            System.out.println("f = " + f);
            if(null == f) {
                return;
            }
            final String selected_description = fc.getSelectedExtensionFilter().getDescription();
            System.out.println("selected_description = " + selected_description);          
            if(selected_description.equals(xmlfilter.getDescription()) && !f.getName().endsWith(".xml")) {
                f = new File(f.getParent(),f.getName()+".xml"); 
            } else if(selected_description.equals(mffilter.getDescription()) && !f.getName().endsWith(".mf")) {
                f = new File(f.getParent(),f.getName()+".mf");
            }
            System.out.println("f = " + f);
        }
    });

    StackPane root = new StackPane();
    root.getChildren().add(btn);

    Scene scene = new Scene(root, 300, 250);

    primaryStage.setTitle("Example");
    primaryStage.setScene(scene);
    primaryStage.show();
}

我在Linux上对其进行了测试，但从未见过它添加.txt.给定的扩展名过滤器可能具有多个扩展名，因此您将不得不选择一个扩展名来任意添加.

I tested it on linux and never saw it add a .txt. A given extension filter might have multiple extensions so you will have to choose one to add arbitrarily.

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