将文件从操作系统拖放到Java应用程序（Swing） [英] Drag'n drop files from the OS to Java application (Swing)
本文介绍了将文件从操作系统拖放到Java应用程序（Swing）的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想要的是将文件拖放到一个组件中（例如 JTextArea ）以一种漂亮和亲切的方式（读取：不是全路径，而是一个小图标和名称）。我想要提供一个 JFileChooser 来浏览文件。然后我将依次解析文件以生成我想要的矩阵。
到目前为止，我学到的是框架已经存在，但是还需要定制其他功能。我在Netbeans中创建了一个测试GUI，并尝试将一堆文件拖到一个 JTextArea 上，但它们显示为文件路径，但诚然，它看起来很丑陋。
我非常感谢任何关于如何以一种整洁的方式解决（或澄清）这个问题的提示和指导。请注意，我打算在多个不同的操作系统（Mac，Win和Linux）上使用该软件。
编辑：远远是基于Sun教程的一个例子，如下所示：
import java.awt.datatransfer。*;
import java.awt.event。*;
import java.awt。*;
import java.io. *;
import javax.swing。*;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.border.TitledBorder;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.swing.text。*;
public class ConsolidatorDemo extends JPanel实现ActionListener {
private static final long serialVersionUID = -4487732343062917781L;
JFileChooser fc;
JButton清除;
JTextArea dropZone，console;
JSplitPane childSplitPane，parentSplitPane;
PrintStream ps;
public ConsolidatorDemo（）{
super（new BorderLayout（））;
fc = new JFileChooser（）;;
fc.setMultiSelectionEnabled（true）;
fc.setDragEnabled（true）;
fc.setControlButtonsAreShown（false）;
fc.setFileSelectionMode（JFileChooser.FILES_ONLY）;
JPanel fcPanel = new JPanel（new BorderLayout（））;
fcPanel.add（fc，BorderLayout.CENTER）;
clear = new JButton（全部清除）;
clear.addActionListener（this）;
JPanel buttonPanel = new JPanel（new BorderLayout（））;
buttonPanel.setBorder（BorderFactory.createEmptyBorder（5,5,5,5））;
buttonPanel.add（clear，BorderLayout.LINE_END）;
JPanel leftUpperPanel = new JPanel（new BorderLayout（））;
leftUpperPanel.setBorder（BorderFactory.createEmptyBorder（5,5,5,5））;
leftUpperPanel.add（fcPanel，BorderLayout.CENTER）;
leftUpperPanel.add（buttonPanel，BorderLayout.PAGE_END）;
JScrollPane leftLowerPanel = new javax.swing.JScrollPane（）;
leftLowerPanel.setBorder（BorderFactory.createEmptyBorder（5,5,5,5））;
dropZone = new JTextArea（）;
dropZone.setColumns（20）;
dropZone.setLineWrap（true）;
dropZone.setRows（5）;
dropZone.setDragEnabled（true）;
dropZone.setDropMode（javax.swing.DropMode.INSERT）;
dropZone.setBorder（new TitledBorder（Selected files / folders））;
leftLowerPanel.setViewportView（dropZone）;
childSplitPane = new JSplitPane（JSplitPane.VERTICAL_SPLIT，
leftUpperPanel，leftLowerPanel）;
childSplitPane.setDividerLocation（400）;
childSplitPane.setPreferredSize（new Dimension（480，650））;
console = new JTextArea（）;
console.setColumns（40）;
console.setLineWrap（true）;
console.setBorder（new TitledBorder（Console））;
parentSplitPane = new JSplitPane（JSplitPane.HORIZONTAL_SPLIT，
childSplitPane，console）;
parentSplitPane.setDividerLocation（480）;
parentSplitPane.setPreferredSize（new Dimension（800，650））;
add（parentSplitPane，BorderLayout.CENTER）;
}
public void setDefaultButton（）{
getRootPane（）。setDefaultButton（clear）;
}
public void actionPerformed（ActionEvent e）{
if（e.getSource（）== clear）{
dropZone.setText（）;
}
}
/ **
*创建GUI并显示它。对于线程安全性，
*此方法应从
*事件调度线程调用。
* /
private static void createAndShowGUI（）{
//确保我们有漂亮的窗口装饰。
JFrame.setDefaultLookAndFeelDecorated（true）;
try {
//UIManager.setLookAndFeel(\"de.javasoft.plaf.synthetica.SyntheticaBlackStarLookAndFeel）;
for（LookAndFeelInfo info：UIManager.getInstalledLookAndFeels（））{
if（Nimbus.equals（info.getName（）））{
UIManager.setLookAndFeel（info.getClassName（）） ;
break;
}
}
} catch（Exception e）{
e.printStackTrace（）;
}
//创建并设置窗口。
JFrame frame = new JFrame（Consolidator！）;
frame.setDefaultCloseOperation（JFrame.DISPOSE_ON_CLOSE）;
//创建并设置菜单栏和内容窗格。
ConsolidatorDemo demo = new ConsolidatorDemo（）;
demo.setOpaque（true）; //内容窗格必须是不透明的
frame.setContentPane（demo）;
//显示窗口。
frame.pack（）;
frame.setVisible（true）;
demo.setDefaultButton（）;
}
public static void main（String [] args）{
//为事件调度线程安排一个作业：
//创建并显示此应用程序的GUI。
javax.swing.SwingUtilities.invokeLater（new Runnable（）{
public void run（）{
createAndShowGUI（）;
}
}）;
}
解决方案
这是一个快速的代码片段导入实际的文件到JList（而不是将其String表示形式导入到文本组件中），并使用自定义渲染器来呈现它。它是从BasicDnD（在教程中）改编的：
fileDropper = new JList（new DefaultListModel（））;
fileDropper.setDragEnabled（true）;
leftLowerPanel.setViewportView（fileDropper）;
TransferHandler handler = new TransferHandler（）{
@Override
public boolean canImport（TransferHandler.TransferSupport info）{
//我们只导入FileList
if（！info.isDataFlavorSupported（DataFlavor.javaFileListFlavor））{
return false;
}
返回true;
}
@Override
public boolean importData（TransferHandler.TransferSupport info）{
if（！info.isDrop（））{
return false;
}
//检查FileList flavor
如果（！info.isDataFlavorSupported（DataFlavor.javaFileListFlavor））{
displayDropLocation（List不接受drop ）;
返回false;
}
//获取正在删除的fileList。
可传递t = info.getTransferable（）;
列表<文件>数据;
try {
data =（List< File>）t.getTransferData（DataFlavor.javaFileListFlavor）;
}
catch（异常e）{return false; }
DefaultListModel model =（DefaultListModel）fileDropper.getModel（）;
（文件文件：数据）{
model.addElement（file）;
}
返回true;
}
private void displayDropLocation（String string）{
System.out.println（string）;
}
};
fileDropper.setTransferHandler（handler）;
fileDropper.setCellRenderer（new DefaultListRenderer（
StringValues.FILE_NAME，IconValues.FILE_ICON））;
无法阻止显示SwingX渲染器配置:-)在核心java中，您可以手动，像
class MyRenderer extends DefaultListCellRenderer {
@Override
public Component getListCellRendererComponent ...）{
super.getList ...
if（value instanceof File）{
setText（FileSystemView.getFileSystemView（）。getDisplayName（value）;
setIcon（FileSystemView .getFileSystemView（）。getSystemIcon（value）;
}
return this;
}
}
Let me start by saying that I have been reading the drag'n drop tutorial and similar questions asked on SO, but unfortunately I have only gotten more confused about this matter. What I want to achieve is relatively simple so I am surprised that it got me in so much trouble already. I am writing a small utility application which will consolidate a bunch of result files (custom defined xml-type) into a large tab-separated text file. Most of the functionality is already coded, however I wanted to make a decent GUI for it.
What I want is to be able to drag'n drop files into a component (for instance JTextArea) in a nice and gracious way (read: not full paths, but instead a small icon and name). I would like to be able to supply a JFileChooser to browse for files as well. I will then parse the files sequentially to produce the matrix I want.
What I have learned so far is that the framework is already there however any additional functionality needs to be custom built. I have created a test GUI in Netbeans and tried to drag a bunch of files onto a JTextArea, but they appear as file paths, and admittedly it looks very ugly.
I would really appreciate any tips and guidance on how to solve (or clarify) this problem in a neat way. Note that I do intend to use the software on multiple different OS (Mac,Win and Linux).
EDIT: the code I have so far is based on one of the examples from Sun tutorials and is as follows
import java.awt.datatransfer.*;
import java.awt.event.*;
import java.awt.*;
import java.io.*;
import javax.swing.*;
import javax.swing.UIManager.LookAndFeelInfo;
import javax.swing.border.TitledBorder;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.swing.text.*;
public class ConsolidatorDemo extends JPanel implements ActionListener {
private static final long serialVersionUID = -4487732343062917781L;
JFileChooser fc;
JButton clear;
JTextArea dropZone, console;
JSplitPane childSplitPane, parentSplitPane;
PrintStream ps;
public ConsolidatorDemo() {
super(new BorderLayout());
fc = new JFileChooser();;
fc.setMultiSelectionEnabled(true);
fc.setDragEnabled(true);
fc.setControlButtonsAreShown(false);
fc.setFileSelectionMode(JFileChooser.FILES_ONLY);
JPanel fcPanel = new JPanel(new BorderLayout());
fcPanel.add(fc, BorderLayout.CENTER);
clear = new JButton("Clear All");
clear.addActionListener(this);
JPanel buttonPanel = new JPanel(new BorderLayout());
buttonPanel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
buttonPanel.add(clear, BorderLayout.LINE_END);
JPanel leftUpperPanel = new JPanel(new BorderLayout());
leftUpperPanel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
leftUpperPanel.add(fcPanel, BorderLayout.CENTER);
leftUpperPanel.add(buttonPanel, BorderLayout.PAGE_END);
JScrollPane leftLowerPanel = new javax.swing.JScrollPane();
leftLowerPanel.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
dropZone = new JTextArea();
dropZone.setColumns(20);
dropZone.setLineWrap(true);
dropZone.setRows(5);
dropZone.setDragEnabled(true);
dropZone.setDropMode(javax.swing.DropMode.INSERT);
dropZone.setBorder(new TitledBorder("Selected files/folders"));
leftLowerPanel.setViewportView(dropZone);
childSplitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
leftUpperPanel, leftLowerPanel);
childSplitPane.setDividerLocation(400);
childSplitPane.setPreferredSize(new Dimension(480, 650));
console = new JTextArea();
console.setColumns(40);
console.setLineWrap(true);
console.setBorder(new TitledBorder("Console"));
parentSplitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
childSplitPane, console);
parentSplitPane.setDividerLocation(480);
parentSplitPane.setPreferredSize(new Dimension(800, 650));
add(parentSplitPane, BorderLayout.CENTER);
}
public void setDefaultButton() {
getRootPane().setDefaultButton(clear);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == clear) {
dropZone.setText("");
}
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Make sure we have nice window decorations.
JFrame.setDefaultLookAndFeelDecorated(true);
try {
//UIManager.setLookAndFeel("de.javasoft.plaf.synthetica.SyntheticaBlackStarLookAndFeel");
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
}catch (Exception e){
e.printStackTrace();
}
//Create and set up the window.
JFrame frame = new JFrame("Consolidator!");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
//Create and set up the menu bar and content pane.
ConsolidatorDemo demo = new ConsolidatorDemo();
demo.setOpaque(true); //content panes must be opaque
frame.setContentPane(demo);
//Display the window.
frame.pack();
frame.setVisible(true);
demo.setDefaultButton();
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
解决方案
here's a quick snippet to import the actual Files into a JList (as opposed to importing its String representation into a text component) and use a custom renderer to present it nicely. It's adapted from the BasicDnD (in the tutorial):
fileDropper = new JList(new DefaultListModel());
fileDropper.setDragEnabled(true);
leftLowerPanel.setViewportView(fileDropper);
TransferHandler handler = new TransferHandler() {
@Override
public boolean canImport(TransferHandler.TransferSupport info) {
// we only import FileList
if (!info.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
return false;
}
return true;
}
@Override
public boolean importData(TransferHandler.TransferSupport info) {
if (!info.isDrop()) {
return false;
}
// Check for FileList flavor
if (!info.isDataFlavorSupported(DataFlavor.javaFileListFlavor)) {
displayDropLocation("List doesn't accept a drop of this type.");
return false;
}
// Get the fileList that is being dropped.
Transferable t = info.getTransferable();
List<File> data;
try {
data = (List<File>)t.getTransferData(DataFlavor.javaFileListFlavor);
}
catch (Exception e) { return false; }
DefaultListModel model = (DefaultListModel) fileDropper.getModel();
for (File file : data) {
model.addElement(file);
}
return true;
}
private void displayDropLocation(String string) {
System.out.println(string);
}
};
fileDropper.setTransferHandler(handler);
fileDropper.setCellRenderer(new DefaultListRenderer(
StringValues.FILE_NAME, IconValues.FILE_ICON));
Couldn't resist to showing SwingX renderer config :-) In core java, you would do it manually, something like
class MyRenderer extends DefaultListCellRenderer {
@Override
public Component getListCellRendererComponent(...) {
super.getList...
if (value instanceof File) {
setText(FileSystemView.getFileSystemView().getDisplayName(value);
setIcon(FileSystemView.getFileSystemView().getSystemIcon(value);
}
return this;
}
}
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