fix(gui): support filtering files with multiple extensions in file dialog (PR #2185)

* fix(gui): support filtering files with multiple extensions in file dialog

* lint

jadx-gui/src/main/java/jadx/gui/ui/filedialog/CustomFileChooser.java

@@ -13,7 +13,6 @@ import javax.swing.JDialog;
 import javax.swing.JFileChooser;
 import javax.swing.JOptionPane;
 import javax.swing.UIManager;
-import javax.swing.filechooser.FileNameExtensionFilter;
 
 import jadx.api.plugins.utils.CommonFileUtils;
 import jadx.core.utils.Utils;
@@ -44,7 +43,7 @@ class CustomFileChooser extends JFileChooser {
 		List<String> fileExtList = data.getFileExtList();
 		if (Utils.notEmpty(fileExtList)) {
 			String description = NLS.str("file_dialog.supported_files") + ": (" + Utils.listToString(fileExtList) + ')';
-			setFileFilter(new FileNameExtensionFilter(description, fileExtList.toArray(new String[0])));
+			setFileFilter(new FileNameMultiExtensionFilter(description, fileExtList.toArray(new String[0])));
 		}
 		if (data.getSelectedFile() != null) {
 			setSelectedFile(data.getSelectedFile().toFile());

jadx-gui/src/main/java/jadx/gui/ui/filedialog/FileNameMultiExtensionFilter.java

@@ -0,0 +1,42 @@
+package jadx.gui.ui.filedialog;
+
+import java.io.File;
+
+import javax.swing.filechooser.FileFilter;
+import javax.swing.filechooser.FileNameExtensionFilter;
+
+/**
+ * Custom file filter for filtering files with multiple extensions.
+ * It overcomes the limitation of {@link FileNameExtensionFilter},
+ * which treats only the last file extension split by dots as the
+ * file extension, and does not support multiple extensions such as
+ * {@code .jadx.kts}.
+ */
+class FileNameMultiExtensionFilter extends FileFilter {
+	private final FileNameExtensionFilter delegate;
+	private final String[] extensions;
+
+	public FileNameMultiExtensionFilter(String description, String... extensions) {
+		this.delegate = new FileNameExtensionFilter(description, extensions[0]);
+		this.extensions = extensions;
+	}
+
+	@Override
+	public boolean accept(File file) {
+		if (file.isDirectory()) {
+			return true;
+		}
+		String fileName = file.getName();
+		for (String extension : extensions) {
+			if (fileName.endsWith(extension)) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	@Override
+	public String getDescription() {
+		return delegate.getDescription();
+	}
+}