swing - 我的 Eclipse 检测到错误

Question

我的有什么问题，FileFilter 说它不能证明

import javax.swing.*; 
import javax.swing.filechooser.FileFilter;

import java.io.File;    

public class fileChooser2 extends Object {
public fileChooser2() {
JFileChooser chooser = new JFileChooser();
   // Note: source for ExampleFileFilter can be found in FileChooserDemo,
   // under the demo/jfc directory in the JDK.
   FileFilter filter = new FileFilter();
   filter.addExtension("jpg");
   filter.addExtension("gif");
   filter.setDescription("JPG & GIF Images");
   chooser.setFileFilter(filter);
   int returnVal = chooser.showOpenDialog(parent);
   if(returnVal == JFileChooser.APPROVE_OPTION) {
      System.out.println("You chose to open this file: " +
           chooser.getSelectedFile().getName());


}
}
}

Answer 1

FileFilter是一个abstract类（这意味着它不能被实例化），你必须扩展它。有关. FileNameExtensionFilter_ FileFilter您可能还想查看有关如何使用FileChoosers 的教程，其中有一个关于自定义FileFilters的部分

---

如果你使用FileNameExtensionFilter，你可以改变这个

FileFilter filter = new FileFilter();
filter.addExtension("jpg");
filter.addExtension("gif");
filter.setDescription("JPG & GIF Images");

对此

FileNameExtensionFilter filter = new FileNameExtensionFilter("JPG & GIF Images", "jpg", "gif");