Java 如何使用JTree在JPanel中显示目录中的文件?
我正在使用Swing开发GUI。GUI的实现方式是,当用户希望加载一组文本文件时,应打开文件选择器对话框,用户选择所有文件所在的目录。现在,我想使用JTree将所选目录中的所有文件列在一个JScrollPane中。我使用此示例在代码中实现JTree: 但是,在我选择目录后,JTree不会显示在JPanel中。我已经将JTree代码放在actionPerformed()方法中。我不确定这是不是正确的方法 代码如下:Java 如何使用JTree在JPanel中显示目录中的文件?,java,swing,user-interface,jtree,jtreetable,Java,Swing,User Interface,Jtree,Jtreetable,我正在使用Swing开发GUI。GUI的实现方式是,当用户希望加载一组文本文件时,应打开文件选择器对话框,用户选择所有文件所在的目录。现在,我想使用JTree将所选目录中的所有文件列在一个JScrollPane中。我使用此示例在代码中实现JTree: 但是,在我选择目录后,JTree不会显示在JPanel中。我已经将JTree代码放在actionPerformed()方法中。我不确定这是不是正确的方法 代码如下: public void actionPerformed(ActionEvent
public void actionPerformed(ActionEvent e) {
//Handle open button action.
if (e.getSource() == OpenFileButton) {
int returnVal = fc.showOpenDialog(GUIMain.this);
if (returnVal == JFileChooser.APPROVE_OPTION) {
file = fc.getSelectedFile();
System.out.println(file);
File[] filesInDirectory = file.listFiles();
SortFile sf = new SortFile();
// Calls sortByNumber method in class SortFile to list the files number wise
filesInDirectory = sf.sortByNumber(filesInDirectory);
FileTreeModel model = new FileTreeModel(file);
tree = new JTree();
tree.setModel(model);
spectralFilesScrollPane = new JScrollPane(tree);
// add(BorderLayout.CENTER, spectralFilesScrollPane);
spectralFilesScrollPane.setVerticalScrollBarPolicy(
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
spectralFilesScrollPane.setPreferredSize(new Dimension(250, 145));
spectralFilesScrollPane.setMinimumSize(new Dimension(10, 10));
spectralFilesScrollPane.setBorder(
BorderFactory.createCompoundBorder(
BorderFactory.createTitledBorder("Spectral Files"),
BorderFactory.createEmptyBorder(5, 5, 5, 5)));
content.add(spectralFilesScrollPane);
spectralFilesScrollPane.setVisible(true);
}
}
}
FileTreeModel.java类
import javax.swing.event.TreeModelListener;
import javax.swing.tree.TreeModel;
import javax.swing.*;
import javax.swing.tree.TreePath;
import java.io.File;
/**
* The methods in this class allow the JTree component to traverse
* the file system tree, and display the files and directories.
**/
class FileTreeModel implements TreeModel {
// We specify the root directory when we create the model.
protected File root;
public FileTreeModel(File root) {
System.out.println("I am in FileTree Model");
this.root = root; }
// The model knows how to return the root object of the tree
public Object getRoot() { return root; }
// Tell JTree whether an object in the tree is a leaf or not
public boolean isLeaf(Object node) { return ((File)node).isFile(); }
// Tell JTree how many children a node has
public int getChildCount(Object parent) {
String[] children = ((File)parent).list();
if (children == null) return 0;
System.out.println("printing child length:" + children.length);
return children.length;
}
// Fetch any numbered child of a node for the JTree.
// Our model returns File objects for all nodes in the tree. The
// JTree displays these by calling the File.toString() method.
public Object getChild(Object parent, int index) {
String[] children = ((File)parent).list();
if ((children == null) || (index >= children.length)) return null;
return new File((File) parent, children[index]);
}
// Figure out a child's position in its parent node.
public int getIndexOfChild(Object parent, Object child) {
String[] children = ((File)parent).list();
if (children == null) return -1;
String childname = ((File)child).getName();
for(int i = 0; i < children.length; i++) {
if (childname.equals(children[i])) return i;
}
return -1;
}
// This method is only invoked by the JTree for editable trees.
// This TreeModel does not allow editing, so we do not implement
// this method. The JTree editable property is false by default.
public void valueForPathChanged(TreePath path, Object newvalue) {}
// Since this is not an editable tree model, we never fire any events,
// so we don't actually have to keep track of interested listeners.
public void addTreeModelListener(TreeModelListener l) {}
public void removeTreeModelListener(TreeModelListener l) {}
}
import javax.swing.event.TreeModelListener;
导入javax.swing.tree.TreeModel;
导入javax.swing.*;
导入javax.swing.tree.TreePath;
导入java.io.File;
/**
*此类中的方法允许JTree组件遍历
*文件系统树,并显示文件和目录。
**/
类FileTreeModel实现TreeModel{
//我们在创建模型时指定根目录。
受保护的文件根;
公共文件树模型(文件根){
System.out.println(“我在文件树模型中”);
this.root=root;}
//模型知道如何返回树的根对象
公共对象getRoot(){return root;}
//告诉JTree树中的对象是否为叶子
公共布尔isLeaf(对象节点){return((文件)节点).isFile();}
//告诉JTree一个节点有多少子节点
public int getChildCount(对象父对象){
字符串[]子项=((文件)父项).list();
if(children==null)返回0;
System.out.println(“打印子长度:+子长度”);
返回子项长度;
}
//获取JTree节点的任意编号子节点。
//我们的模型返回树中所有节点的文件对象
//JTree通过调用File.toString()方法来显示这些内容。
公共对象getChild(对象父对象,int索引){
字符串[]子项=((文件)父项).list();
if((children==null)| |(index>=children.length))返回null;
返回新文件((文件)父级,子级[索引]);
}
//计算子节点在其父节点中的位置。
public int getIndexOfChild(对象父对象、对象子对象){
字符串[]子项=((文件)父项).list();
if(children==null)返回-1;
字符串childname=((文件)child.getName();
for(int i=0;i
重新验证内容容器后,GUI如下所示:
您尚未重新验证包含
内容的容器。在actionPerformed方法的末尾,添加行
//content.invalidate();
content.revalidate();
content.repaint();
是的,这是我想要的。然而,对于显示器,我得到了一个单独的框,在JPanel Spectrum文件中有滚动条,它是samller。JPanel和JScrollPane的维度在代码中是相同的。我已经更新了关于GUI外观的问题。我能够得到期望的结果。