我正在尝试做的是，当我运行我的应用程序时，它启动线程并显示图像3秒（3000毫秒），然后线程停止运行。
图像路径正确，图像文件存在，线程本身运行;但是，图像似乎没有显示出来。可能有什么不对？这是我的代码：
package org.main;
import java.awt.Graphics;
import java.awt.Image;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
public class Splasher extends JPanel implements Runnable {
private static final long serialVersionUID = 1L;
Image image;
ImageIcon splash = new ImageIcon("res/splash.png");
public static Thread DrawSplash = new Thread(new Splasher());
public Splasher() {
setFocusable(true);
image = splash.getImage();
repaint();
}
boolean hasRan = false;
public void run() {
try {
System.out.println("Drawing Splash Screen");
repaint();
Thread.sleep(3000);
System.out.println("Repainted");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public void paint(Graphics g) {
g.drawImage(image, 0, 0, null);
}
public Image getImage() {
return image;
}
}
答案 0 :(得分：2)
你的问题还不够。
您没有展示如何使用初始屏幕，如果它附加到任何内容或如何开始/使用Thread。
所以问题可能是什么......
除了VishalK已经指出的其他内容之外，我想添加public static Thread DrawSplash = new Thread(new Splasher())是一个坏主意。您不应该使用static Thread s线程是不可重入的，也就是说，您可以运行相同的线程两次。
这是一个展示“褪色”闪屏的小例子，使用了许多Swing Timer s
这假设您使用的是Java 7，它可以使它适用于Java 6，我没有发布该代码。
public class TestSplashScreen01 {
public static void main(String[] args) {
new TestSplashScreen01();
}
public TestSplashScreen01() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
SplashScreen splash = new SplashScreen();
splash.start();
}
});
}
public class SplashScreen extends JWindow {
private SplashPane splash;
public SplashScreen() {
setBackground(new Color(0, 0, 0, 0));
splash = new SplashPane();
add(splash);
pack();
setLocationRelativeTo(null);
}
public void start() {
splash.start();
}
public class SplashPane extends JPanel {
private BufferedImage splash;
private Timer timer;
private float alpha = 0f;
private int duration = 1000;
private long startTime = -1;
public SplashPane() {
try {
splash = ImageIO.read(getClass().getResource("/res/SokahsScreen.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
timer = new Timer(3000, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
fadeOut();
}
});
timer.setRepeats(false);
}
protected void fadeOut() {
Timer fadeInTimer = new Timer(40, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
long now = System.currentTimeMillis();
long runTime = now - startTime;
alpha = 1f - ((float) runTime / (float) duration);
if (alpha <= 0.01f) {
alpha = 0f;
((Timer) (e.getSource())).stop();
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
dispose();
}
});
}
repaint();
}
});
startTime = System.currentTimeMillis();
fadeInTimer.setRepeats(true);
fadeInTimer.setCoalesce(true);
fadeInTimer.start();
}
protected void fadeIn() {
Timer fadeInTimer = new Timer(40, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
long now = System.currentTimeMillis();
long runTime = now - startTime;
alpha = (float) runTime / (float) duration;
if (alpha >= 1f) {
alpha = 1f;
((Timer) (e.getSource())).stop();
timer.start();
}
repaint();
}
});
startTime = System.currentTimeMillis();
fadeInTimer.setRepeats(true);
fadeInTimer.setCoalesce(true);
fadeInTimer.start();
}
public void start() {
if (!SplashScreen.this.isVisible()) {
alpha = 0f;
SplashScreen.this.setVisible(true);
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
fadeIn();
}
});
}
}
@Override
public Dimension getPreferredSize() {
return splash == null ? super.getPreferredSize() : new Dimension(splash.getWidth(), splash.getHeight());
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (splash != null) {
Graphics2D g2d = (Graphics2D) g.create();
g2d.setComposite(AlphaComposite.SrcOver.derive(alpha));
int x = (getWidth() - splash.getWidth()) / 2;
int y = (getHeight() - splash.getHeight()) / 2;
g2d.drawImage(splash, x, y, this);
g2d.dispose();
}
}
}
}
}
NB：
这个例子的问题是，一旦你调用start，程序将继续执行，这将需要某种监听器在启动屏幕完成时告诉感兴趣的各方。
或者，您可以使用未修饰的模式JDialog
答案 1 :(得分：1)
您在代码中犯下的许多错误......
paint方法而不是paintComponent来绘制图片。Thread在Swing组件（JPanel）上绘制和删除图片。您应该使用javax.swing.Timer代替。javax.swing.Timer，但您仍然犯的基本错误是您创建了一个静态线程，并在其中传递了Splasher的新对象而不是当前对象。Component的图形中进行更改时，您应该明确调用repaint。例如，如果您希望图像在3秒后消失，则应在3秒钟后调用repaint方法，并且应在paintComponent方法中写入正确的逻辑以删除该图像。以下是您的代码的修改版本，它正在完成您正在寻找的内容。看看它。：
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentAdapter;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.Timer;
import javax.swing.SwingUtilities;
public class Splasher extends JPanel {
private static final long serialVersionUID = 1L;
Image image;
ImageIcon splash = new ImageIcon("apple.png");
MyComponentListener componentListener ;
Timer timer ;
public Splasher()
{
componentListener = new MyComponentListener();
setFocusable(true);
image = splash.getImage();
timer = new Timer(3000, new LoadAction());
addComponentListener(componentListener);
}
boolean hasRan = false;
@Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
if (image == null && timer !=null )
{
g.clearRect(0, 0, getWidth(), getHeight()) ;
timer.stop();
removeComponentListener(componentListener);
}
else
{
g.drawImage(image, 0, 0, null);
}
}
public Image getImage()
{
return image;
}
private class MyComponentListener extends ComponentAdapter
{
@Override
public void componentResized(ComponentEvent evt)
{
System.out.println("Resized..");
timer.start();
}
}
private class LoadAction implements ActionListener
{
public void actionPerformed(ActionEvent evt)
{
System.out.println("Drawing Splash Screen");
repaint();
image = null;
repaint();
System.out.println("Repainted");
}
}
public static void main(String st[])
{
SwingUtilities.invokeLater ( new Runnable()
{
@Override
public void run()
{
JFrame frame = new JFrame("Splash:");
frame.getContentPane().add(new Splasher());
frame.setSize(300,500);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
});
}
}
另请参阅以下有关Java中的Paint机制的教程。 http://docs.oracle.com/javase/tutorial/uiswing/painting/closer.html