我正在尝试用Java创建一个图像编辑器，我需要从GUI中显示图像。我试图从JFileChooser中选择文件并在JFrame中的JPanel中显示该文件。我无法从JFileChooser获取文件并且还要显示图像。我真的需要帮助这两件事。
这是我的主要课程（ImagePanel）：
import java.awt.Dimension;
import javax.swing.ImageIcon;
import java.awt.Graphics;
import javax.swing.JFrame;
import java.awt.Color;
import javax.swing.JPanel;
import java.awt.BorderLayout;
public class ImagePanel extends JFrame {
public ImagePanel( String name) {
String nme= name;
FileChooserDemo a = new FileChooserDemo();
ImagePanel2 img = new ImagePanel2("hockey.jpg");
add(img);
add(a);
System.out.println(getFile());
}
public static void main (String[]args) {
ImagePanel x = new ImagePanel ("Image Deluxe");
x.setBounds(100, 100, 300, 200);
x.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
x.setVisible(true);
}
}
这是我的第二堂课（ImagePanel2）：
import java.awt.Dimension;
import javax.swing.ImageIcon;
import java.awt.Graphics;
import javax.swing.JFrame;
import java.awt.Color;
import javax.swing.JPanel;
import java.util.Scanner;
public class ImagePanel2 extends JPanel {
private ImageIcon image;
public ImagePanel2(String imageFileName) {
image = new ImageIcon(imageFileName);
}
public void paintComponent(Graphics g) {
int x = 5, y = 10;
if (image != null)
image.paintIcon(this, g, x, y);
else
System.out.println("Image File not found");
}
public static void main(String[] argv) {
// Scanner keyboard = new Scanner(System.in);
// System.out.print("Enter the name of the File: ");
// String fileName=keyboard.next();
JPanel canvas2 = new ImagePanel2("hockey.jpg");
JFrame window= new JFrame("Images");
window.setBounds(100, 100, 300, 200);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
canvas2.setBackground(Color.WHITE);
window.getContentPane().add(canvas2);
window.setVisible(true);
}
}
这里是JFileChooser的类（从Java网站复制的FileChooserDemo）：
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.SwingUtilities;
import javax.swing.filechooser.*;
/*
* FileChooserDemo.java uses these files:
* images/Open16.gif
* images/Save16.gif
*/
public class FileChooserDemo extends JPanel
implements ActionListener {
public File testFile;
static private final String newline = "\n";
JButton openButton, saveButton;
JTextArea log;
JFileChooser fc;
public FileChooserDemo() {
super(new BorderLayout());
//Create the log first, because the action listeners
//need to refer to it.
//log = new JTextArea(5,20);
//log.setMargin(new Insets(5,5,5,5));
//log.setEditable(false);
//JScrollPane logScrollPane = new JScrollPane(log);
//Create a file chooser
fc = new JFileChooser();
//Uncomment one of the following lines to try a different
//file selection mode. The first allows just directories
//to be selected (and, at least in the Java look and feel,
//shown). The second allows both files and directories
//to be selected. If you leave these lines commented out,
//then the default mode (FILES_ONLY) will be used.
//
//fc.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
//fc.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
//Create the open button. We use the image from the JLF
//Graphics Repository (but we extracted it from the jar).
openButton = new JButton("Open a File...",
createImageIcon("images/Open16.gif"));
openButton.addActionListener(this);
//Create the save button. We use the image from the JLF
//Graphics Repository (but we extracted it from the jar).
saveButton = new JButton("Save a File...",
createImageIcon("images/Save16.gif"));
saveButton.addActionListener(this);
//For layout purposes, put the buttons in a separate panel
JPanel buttonPanel = new JPanel(); //use FlowLayout
buttonPanel.add(openButton);
buttonPanel.add(saveButton);
//Add the buttons and the log to this panel.
add(buttonPanel, BorderLayout.PAGE_START);
//add(logScrollPane, BorderLayout.CENTER);
}
public void actionPerformed(ActionEvent e) {
//Handle open button action.
if (e.getSource() == openButton) {
int returnVal = fc.showOpenDialog(FileChooserDemo.this);
if (returnVal == JFileChooser.APPROVE_OPTION) {
testFile = fc.getSelectedFile();
//This is where a real application would open the file.
//log.append("Opening: " + file.getName() + "." + newline);
} else {
//log.append("Open command cancelled by user." + newline);
}
//log.setCaretPosition(log.getDocument().getLength());
//Handle save button action.
} else if (e.getSource() == saveButton) {
int returnVal = fc.showSaveDialog(FileChooserDemo.this);
if (returnVal == JFileChooser.APPROVE_OPTION) {
File file = fc.getSelectedFile();
//This is where a real application would save the file.
//log.append("Saving: " + file.getName() + "." + newline);
} else {
//log.append("Save command cancelled by user." + newline);
}
log.setCaretPosition(log.getDocument().getLength());
}
}
/** Returns an ImageIcon, or null if the path was invalid. */
protected static ImageIcon createImageIcon(String path) {
java.net.URL imgURL = FileChooserDemo.class.getResource(path);
if (imgURL != null) {
return new ImageIcon(imgURL);
} else {
System.err.println("Couldn't find file: " + path);
return null;
}
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event dispatch thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("FileChooserDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Add content to the window.
frame.add(new FileChooserDemo());
//Display the window.
frame.pack();
frame.setVisible(true);
}
public File getFile() {
return testFile;
}
public static void main(String[] args) {
//Schedule a job for the event dispatch thread:
//creating and showing this application's GUI.
SwingUtilities.invokeLater(
new Runnable() {
public void run() {
//Turn off metal's use of bold fonts
UIManager.put("swing.boldMetal", Boolean.FALSE);
createAndShowGUI();
}
});
}
}
我在FileChooserDemo中使用getFile（）方法公开，我试图在ImagePanel中使用它来访问FileChooser选择的文件名，但ImagePanel无法识别getFile（）方法。任何帮助，将不胜感激。感谢。
答案 0 :(得分：0)
在ImagePanel替换
System.out.println(getFile());
与
System.out.println(a.getFile());