显示动画BG在Swing [英] Show an animated BG in Swing

问题描述

这是动画（循环）GIF可以显示在的JLabel 或HTML（在格式文本组件，如的JEditorPane ），并可以看到循环。

An animated (cycling) GIF can be displayed in a JLabel or in HTML (in formatted text components like JEditorPane) and be seen to cycle.

但要加载图像画作为容器的背景下，我想一般使用 ImageIO.read（）或 Toolkit.getImage （）（当我感到怀念起上个千年后者）。在骑自行车的图像加载图像的结果既不是方法，通常只是第一帧。

But to load an image to paint as the background of a container, I would typically use either ImageIO.read() or Toolkit.getImage() (the latter when I'm feeling nostalgic for the last millennium). Neither method of loading an image results in a cycling image, it is typically just the first frame.

如何加载的动画的一个背景图片？

How to load an animated image for a background?

推荐答案

使用的ImageIcon 可能是做的最简单的事情。几件事情要记住：

Using ImageIcon is probably the most straightforward thing to do. A couple of things to keep in mind:

• 的ImageIcon（URL）本身利用 Toolkit.getImage（URL）的。 的getImage（）可以使用缓存或共享图像 - 您可以使用 Toolkit.createImage（URL）而不是preFER数据。

• ImageIcon(URL) itself makes use of Toolkit.getImage(URL). You may prefer using Toolkit.createImage(URL) instead - getImage() may use cached or shared image data.

的ImageIcon 利用了一个媒体跟踪​​来有效地等待，直到图像完全加载。

ImageIcon makes use of a MediaTracker to effectively wait until the image is completely loaded.

所以，您的问题可能不是使用工具包（的ImageIO 是一个不同的野兽），而是事实上，你不渲染满载的形象。尝试一个有趣的事情是：

So, your issue may not be the use of Toolkit (ImageIO is a different beast), but rather the fact that you're not rendering a fully loaded image. One interesting thing to try would be:

Image image = f.getToolkit().createImage(url);
//...
ImagePanel imagePanel = new ImagePanel(image);
imagePanel.prepareImage(image, imagePanel);
//...

我的挥杆/ AWT / J2D可能有点模糊，但这个想法是，既然你的 ImagePanel 是的ImageObserver ，它可被异步关于图像信息通知。在 Component.imageUpdate（）方法应该调用重绘需要。

My Swing/AWT/J2D may be a bit fuzzy, but the idea is that since your ImagePanel is an ImageObserver, it can be notified asynchronously about image information. The Component.imageUpdate() method should invoke repaint as needed.

编辑：

由于在评论中指出，不要求 prepareImage 通话 - 一个工作示例如下所示。最关键的是，该覆盖的paintComponent 方法调用 Graphics.drawImage ，它提供了 ImageObserver的挂钩。在 imageUpdate的方法（在 java.awt.Component中实施）将连续与调用 ImageObserver.FRAMEBITS 标志设置。

As noted in the comments, the call to prepareImage is not required - a working example is included below. The key is that the overridden paintComponent method invokes Graphics.drawImage, which provides the ImageObserver hook. The imageUpdate method (implemented in java.awt.Component) will continuously be invoked with the ImageObserver.FRAMEBITS flag set.

import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.image.ImageObserver;
import java.net.MalformedURLException;
import java.net.URL;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;

public class ImagePanel extends JPanel {

    private final Image image;

    public ImagePanel(Image image) {
        super();
        this.image = image;
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(this.image, 0, 0, getWidth(), getHeight(), this);
    }

    public static void main(String[] args) throws MalformedURLException {
        final URL url = new URL("http://pscode.org/media/starzoom-thumb.gif");
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame f = new JFrame("Image");
                f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                f.setLocationByPlatform(true);

                Image image = f.getToolkit().createImage(url);
                ImagePanel imagePanel = new ImagePanel(image);
                imagePanel.setLayout(new GridLayout(5, 10, 10, 10));
                imagePanel.setBorder(new EmptyBorder(20, 20, 20, 20));
                for (int ii = 1; ii < 51; ii++) {
                    imagePanel.add(new JButton("" + ii));
                }

                f.setContentPane(imagePanel);
                f.pack();
                f.setVisible(true);
            }
        });
    }
}

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