我想用很好的过渡效果做JButton。我编写了一个由JButton扩展的类，并添加到自定义MouseAdapter。它几乎可以工作，但如果不透明度应该为0，那么我的一个BufferedImage就不会消失。
这是我的所有源代码：
public class ImageHoverButton extends JButton {
public class MouseListener extends MouseAdapter
{
public void mouseExited(MouseEvent me)
{
new Thread(new Runnable()
{
public void run()
{
for (float i = 1f; i >= 0f; i -= .03f)
{
setOpacity(i);
try
{
Thread.sleep(10);
}
catch (Exception e)
{
}
}
}
}).start();
}
public void mouseEntered(MouseEvent me)
{
new Thread(new Runnable()
{
public void run()
{
for (float i = 0f; i <= 1f; i += .03f)
{
setOpacity(i);
try
{
Thread.sleep(10);
}
catch (Exception e)
{
}
}
}
}).start();
}
public void mousePressed(MouseEvent me)
{
new Thread(new Runnable()
{
public void run()
{
for (float i = 1f; i >= 0.6f; i -= .1f)
{
setOpacity(i);
try
{
Thread.sleep(1);
}
catch (Exception e)
{
}
}
}
}).start();
}
}
private static final long serialVersionUID = 1L;
private BufferedImage imgBottom;
private BufferedImage imgHover;
private BufferedImage imgHoverRGB;
// filter to imgInActive
float[] scales = { 1f, 1f, 1f, 0f};
float[] offsets = new float[4];
RescaleOp rop = new RescaleOp(scales, offsets, null);
/**
* Constructor for image path
* @param img
* @param x
* @param y
*/
public ImageHoverButton(String imgBottomPath, String imgHoverPath, int x, int y) {
try {
this.imgBottom = ImageIO.read(new File(imgBottomPath));
this.imgHover = ImageIO.read(new File(imgHoverPath));
imgHoverRGB = new BufferedImage(imgHover.getWidth(null),
imgHover.getHeight(null),
BufferedImage.TYPE_INT_ARGB);
Graphics g = imgHoverRGB.getGraphics();
g.drawImage(imgHover, 0, 0, null);
} catch (IOException e) {
}
this.setBounds(x, y, imgBottom.getWidth() + 40 , imgBottom.getHeight() + 50);
addMouseListener(new MouseListener());
setOpacity(0f);
setOpaque(false);
setBorderPainted(false);
setRolloverEnabled(false);
setCursor(new Cursor(Cursor.HAND_CURSOR));
setLayout(null);
}
public void setOpacity(float opacity) {
scales[3] = opacity;
rop = new RescaleOp(scales, offsets, null);
repaint();
}
public void paint(Graphics g) {
Graphics2D g2d = (Graphics2D)g;
g2d.drawImage(imgBottom, 50, 50, null);
g2d.drawImage(imgHoverRGB, rop, 0, 0);
}
}
知道如何改善这个吗？
答案 0 :(得分：2)
我对RescaleOp不太熟悉，并且不记得曾经使用过这个。但似乎在这种情况下应用它的结果有些出乎意料。
作为替代方案，您可以考虑使用AlphaComposite。然后，实现所需效果所需的最小修改将是更改行
g2d.drawImage(imgHoverRGB, rop, 0, 0);
到
g2d.setComposite(AlphaComposite.getInstance(
AlphaComposite.SRC_OVER, scales[3]));
g2d.drawImage(imgHoverRGB, 0, 0, null);
但是，代码还有其他几个问题：
paint。相反，覆盖paintComponent setBounds（特别是在构造函数中）。展示位置应由布局管理员完成getPreferredSize 我创建了一个示例，显示了一种可能的方法：它包含一个OpacityAnimator，它允许两个不透明度之间的转换，具有预定义的延迟（以毫秒为单位）。当使用鼠标悬停按钮时，此动画制作器用于增加前景图像的不透明度，当鼠标离开按钮时，可以减少此动画。
（请注意，这可以进一步推广，并且有许多可能的＆＃34;配置设置＆＃34;（如转换延迟）可以公开，但这只是作为一个例子）
import java.awt.AlphaComposite;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class HoverButtonTest
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
@Override
public void run()
{
try
{
createAndShowGUI();
}
catch (IOException e)
{
e.printStackTrace();
}
}
});
}
private static void createAndShowGUI() throws IOException
{
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
BufferedImage backgroundImage = loadImage("background.png");
BufferedImage foregroundImage = loadImage("foreground.png");
f.getContentPane().setLayout(new FlowLayout());
f.getContentPane().add(
new ImageHoverButton(backgroundImage, foregroundImage));
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
private static BufferedImage loadImage(String path) throws IOException
{
return convertToARGB(ImageIO.read(new File(path)));
}
public static BufferedImage convertToARGB(BufferedImage image)
{
BufferedImage newImage = new BufferedImage(image.getWidth(),
image.getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D g = newImage.createGraphics();
g.drawImage(image, 0, 0, null);
g.dispose();
return newImage;
}
}
class ImageHoverButton extends JButton
{
private class MouseHoverListener extends MouseAdapter
{
@Override
public void mouseExited(MouseEvent me)
{
opacityAnimator.changeOpacity(0.0f, 250);
}
@Override
public void mouseEntered(MouseEvent me)
{
opacityAnimator.changeOpacity(1.0f, 1000);
}
@Override
public void mousePressed(MouseEvent me)
{
opacityAnimator.changeOpacity(0.5f, 50);
}
}
private class OpacityAnimator
{
private final int DELAY_MS = 10;
private final Timer timer;
private float targetOpacity;
private float currentOpacity;
private float opacityStep;
OpacityAnimator()
{
timer = new Timer(DELAY_MS, new ActionListener()
{
@Override
public void actionPerformed(ActionEvent e)
{
if (currentOpacity > targetOpacity)
{
currentOpacity += opacityStep;
currentOpacity = Math.max(
currentOpacity, targetOpacity);
}
else if (currentOpacity < targetOpacity)
{
currentOpacity += opacityStep;
currentOpacity = Math.min(
currentOpacity, targetOpacity);
}
if (currentOpacity == targetOpacity)
{
timer.stop();
}
setOpacity(currentOpacity);
}
});
}
void changeOpacity(float targetOpacity, int durationMs)
{
timer.stop();
this.targetOpacity = targetOpacity;
float delta = targetOpacity - currentOpacity;
if (durationMs > 0)
{
opacityStep = (delta / durationMs) * DELAY_MS;
}
else
{
opacityStep = delta;
}
timer.start();
}
}
private final OpacityAnimator opacityAnimator;
private final BufferedImage backgroundImage;
private final BufferedImage foregroundImage;
private float opacity = 0.0f;
public ImageHoverButton(BufferedImage backgroundImage,
BufferedImage foregroundImage)
{
this.backgroundImage = backgroundImage;
this.foregroundImage = foregroundImage;
this.opacityAnimator = new OpacityAnimator();
addMouseListener(new MouseHoverListener());
setOpaque(false);
setBorderPainted(false);
setRolloverEnabled(false);
setCursor(new Cursor(Cursor.HAND_CURSOR));
}
@Override
public Dimension getPreferredSize()
{
if (super.isPreferredSizeSet())
{
return super.getPreferredSize();
}
int w = Math
.max(backgroundImage.getWidth(), foregroundImage.getWidth());
int h = Math.max(backgroundImage.getHeight(),
foregroundImage.getHeight());
return new Dimension(w, h);
}
public void setOpacity(float opacity)
{
this.opacity = opacity;
repaint();
}
@Override
protected void paintComponent(Graphics gr)
{
super.paintComponent(gr);
Graphics2D g = (Graphics2D) gr;
g.drawImage(backgroundImage, 0, 0, null);
g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER,
opacity));
g.drawImage(foregroundImage, 0, 0, null);
}
}
答案 1 :(得分：0)
不要从其他线程访问Swing组件。请使用摇摆计时器。 见How to use swing timers