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This article will explain in detail how to achieve the gradual effect of Swing. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

Can you let the Swing control also fade and fade? the answer is of course yes. We will also explain the implementation mechanism of these advanced features of Swing. The special effects in Swing can not be achieved by calling a method, but we have to write these methods ourselves, mainly overriding the public void paint (Graphics g) method of Swing. To put it bluntly, all the styles of Swing are "drawn" using the paint method, so Swing is relatively slow, of course, if we consider that Swing is mainly used for client display, a little slower is acceptable.

The following is about the gradual effect of the Swing control. I think the principle is quite simple, just keep changing the transparency of the control. That is, g2d.setComposite (AlphaComposite.getInstance (AlphaComposite.SRC_OVER, alpha))

Here is the complete control code, which you can think of as a JPanel-like container:

Package com.zakisoft.frame; import java.awt.AlphaComposite; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.image.BufferedImage; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import javax.imageio.ImageIO; import javax.swing.Timer / * * @ author zakisoft.com * * / public class ZPanel extends javax.swing.JComponent implements ActionListener {private static final long serialVersionUID = 1L; private BufferedImage image; private static final int ANIMATION_FRAMES = 100; private static final int ANIMATION_INTERVAL = 10; private int frameIndex; / / clock private Timer timer; public BufferedImage getImage () {return image } public void setImage (BufferedImage image) {this.image = image;} private int imgWidth; private int imgHeight; public int getImgWidth () {return imgWidth;} public void setImgWidth (int imgWidth) {this.imgWidth = imgWidth;} public int getImgHeight () {return imgHeight } public void setImgHeight (int imgHeight) {this.imgHeight = imgHeight;} public ZPanel () {} public void setImagePath (String imgPath) {/ / this method is not recommended. This method loads lazily, the image is not loaded into memory, and returns-1 when taking the width and height of the image. / / image = Toolkit.getDefaultToolkit () .getImage (imgPath); try {/ / this method loads the image into memory to get the details of the image. Image = ImageIO.read (new FileInputStream (imgPath));} catch (FileNotFoundException e) {e.printStackTrace ();} catch (IOException e) {e.printStackTrace ();} setImgWidth (image.getWidth (this)); setImgHeight (image.getHeight (this));} public void paintComponent (Graphics g) {int x = 0 Int y = 0; if (null = = image) {return;} g.drawImage (image, x, y, image.getWidth (null), image.getHeight (null), null) } public void paint (Graphics g) {if (isAnimating ()) {/ / content components that display current transparency based on the current frame float alpha = (float) frameIndex / (float) ANIMATION_FRAMES; Graphics2D G2d = (Graphics2D) g; g2d.setComposite (AlphaComposite.getInstance (AlphaComposite.SRC_OVER, alpha)) / / Renderer rendering mechanism super.paint (G2d);} else {/ / if it is * times, start the animation clock frameIndex = 0; timer = new Timer (ANIMATION_INTERVAL, this); timer.start () }} / / determine whether private boolean isAnimating () {return timer! = null & & timer.isRunning ();} / / turn off the clock and reinitialize private void closeTimer () {if (isAnimating ()) {timer.stop (); frameIndex = 0 Timer = null;}} / / Animation clock processing event public void actionPerformed (ActionEvent e) {/ / forward one frame frameIndex++; if (frameIndex > = ANIMATION_FRAMES) / / * one frame, close the animation closeTimer () Else / / Update the current frame repaint ();}}

We use the public void paint (Graphics g) method of the control to set the transparency of the control, and then use the super.paint (G2d) method to redraw the page; when redrawing, the system will automatically call the public void actionPerformed (ActionEvent e) method, where we change the transparency of the control and determine whether the control is loaded or not, and then stop the timer after loading.

Very simple, the effect is good, the attachment is the complete running code. Press the "Picture gradual Show" button to view the effect repeatedly.

The following figure shows the interface at load time:

The following figure shows the loading completion interface:

This is the end of the article on "how to achieve the gradual effect of Swing". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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