我正在尝试用 Java 制作图片查看器，而对于我的生活，我无法让查看器的背景颜色变为黑色。这是我的最新代码：
public class PictureViewer extends JFrame {
static class PauseAction extends AbstractAction {
public void actionPerformed(ActionEvent arg0) {
pauseViewer = !pauseViewer;
}
}
static class QuitAction extends AbstractAction {
public void actionPerformed(ActionEvent e) {
stopViewer = true;
pauseViewer = true;
viewer.setNextToView();
System.exit(0);
}
}
static Double height;
static final String newline = System.getProperty("line.separator");
static boolean pauseViewer = false;
static Dimension screensize = new Dimension();
static boolean stopViewer = false;
static PictureViewer viewer;
static Double width;
JLabel area = new JLabel("", JLabel.CENTER);
int currentPic = 0;
File dir = new File(".");
BufferedImage image;
String path;
Action pauseAction;
int pauseTime = 5;
Action quitAction;
private JScrollPane scrollPane = new JScrollPane(area, JScrollPane.VERTICAL_SCROLLBAR_NEVER,JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
ArrayList<File> thesePictures;
public static void main(String[] args) throws IOException {
//Create and set up the window.
viewer = new PictureViewer();
viewer.setUndecorated(true); //Remove the minimize, maximize and close buttons entirely.
//Get the list of files to display.
viewer.initialize();
//Set up the content pane.
viewer.addComponents();
viewer.setPreferredSize(screensize);
//Display the window.
viewer.pack();
viewer.setVisible(true);
//Start showing pictures.
while (!stopViewer) {
try {
viewer.showPictures();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
//Perform cleanup
viewer.setNextToView();
}
public void addComponents() {
//Set up actions.
pauseAction = new PauseAction();
quitAction = new QuitAction();
scrollPane.getInputMap().put(KeyStroke.getKeyStroke("P"), "doPauseAction");
scrollPane.getActionMap().put("doPauseAction", pauseAction);
scrollPane.getInputMap().put(KeyStroke.getKeyStroke("SPACE"), "doQuitAction");
scrollPane.getActionMap().put("doQuitAction", quitAction);
scrollPane.setBackground(Color.BLACK);
getContentPane().add(scrollPane);
viewer.repaint();
}
public ArrayList<File> getPictures(File dir) {
ArrayList<File> listFiles = new ArrayList<File>(Arrays.asList(dir.listFiles()));
int selectThis = (int) (Math.random() * listFiles.size());
boolean emptyList = true;
if (listFiles.get(selectThis).isDirectory()) {
return getPictures(listFiles.get(selectThis));
} else {
//if the selected file is not a directory, go through the list of files and remove any directories.
ArrayList<File> newList = new ArrayList<File>();
for (File thisFile : listFiles) {
if (!thisFile.isDirectory() && !thisFile.getName().contains(".next") && !thisFile.getName().contains(".jar")) {
newList.add(thisFile);
}
}
listFiles = newList;
}
return listFiles;
}
public void initialize() {
screensize = Toolkit.getDefaultToolkit().getScreenSize();
height = screensize.getHeight();
width = screensize.getWidth();
String filePath = new File(".").getAbsolutePath();
filePath = filePath.substring(0, filePath.length() - 1);
String directory = "";
while (thesePictures == null || thesePictures.size() == 0) {
thesePictures = getPictures(dir);
}
String absolutePath = thesePictures.get(0).getAbsolutePath();
path = absolutePath.substring(0,absolutePath.lastIndexOf(File.separator));
//Look to see if the .next file exists. If so, read in the file object. If not, set the index to 0.
File checkFile = new File(path + "\\.next");
if (checkFile.exists()) {
try {
InputStream inputFile = new FileInputStream(path + "\\.next");
InputStream buffer = new BufferedInputStream(inputFile);
ObjectInput input = new ObjectInputStream(buffer);
File lastViewedPic = (File) input.readObject();
if (thesePictures.contains(lastViewedPic)) {
currentPic = thesePictures.indexOf(lastViewedPic);
} else {
currentPic = 0;
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
System.out.println("Look at " + path + "\\.next");
System.exit(-1);
}
} else {
currentPic = 0;
}
}
public void readInFile(String fileName) {
File file = new File(fileName);
if(file.isFile()) {
try {
image = ImageIO.read(file);
if (image.getWidth() > width || image.getHeight() > height) {
BufferedImage newImage = new BufferedImage(width.intValue(), height.intValue(), BufferedImage.TYPE_INT_RGB);
Graphics2D g = newImage.createGraphics();
g.drawImage(image, 0, 0, width.intValue(), height.intValue(), null);
g.dispose();
image = newImage;
}
} catch (IOException e) {
showMessageDialog(viewer,"Does not compute !","No file read or found",INFORMATION_MESSAGE);
e.printStackTrace();
} catch (Exception e) {
showMessageDialog(viewer, "Problem: " + e.getLocalizedMessage());
}
}
}
public void setImage(JLabel area){
ImageIcon icon = new ImageIcon(image);
area.setIcon(icon);
viewer.repaint();
}
protected void setNextToView() {
//See if the next picture to view file exists. If not, create it.
File checkFile = new File(path + "\\.next");
if (!checkFile.exists()) {
try {
checkFile.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
FileOutputStream outputFile = new FileOutputStream(path + "\\.next");
ObjectOutputStream writer = new ObjectOutputStream(outputFile);
writer.writeObject(thesePictures.get(currentPic));
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
private void showPictures() throws InterruptedException {
while (!pauseViewer) {
//If we reach the last file in the directory, switch to another directory (it could be the same directory).
if (currentPic + 1 == thesePictures.size()) {
currentPic = 0;
thesePictures = new ArrayList<File>();
while (thesePictures == null || thesePictures.size() == 0) {
thesePictures = getPictures(dir);
}
} else {
currentPic += 1;
}
readInFile(thesePictures.get(currentPic).getAbsolutePath());
setImage(area);
TimeUnit.SECONDS.sleep(pauseTime);
}
}
}
只是我做错了什么？
谢谢！