这篇文章的目的是弄清楚为什么它在两个按钮上复制两个图像。这很奇怪,不应该发生。这是主要目标。然后就会找到解决方案。谢谢!
它的样子的图像
我已经做了 MRE
它在两个按钮上输出两个图像,我不知道为什么。
import java.awt.Color;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class GameManager extends JFrame{
private final Map <String, String> images = new HashMap<>(2);
GameManager()
{
images.put("Articuno", "https://i.ya-webdesign.com/images/articuno-transparent-pokemon-xy-17.gif");
images.put("Rayquaza", "https://play.pokemonshowdown.com/sprites/ani-back-shiny/rayquaza.gif");
JPanel pnlPokemonInParty = new JPanel(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
//Why does it put both images on both buttons? It actually sets the images on top of one another.
//You can tell which image is in the front and which is behind the other.
//I'm setting the buttons to be transparent. Setting the buttons to not be transparent will cover the the image below it,
//that's how I know they're being stacked on top of one another.
JButton btn1 = gifBtn("Articuno");
JButton btn2 = gifBtn("Rayquaza");
c.gridx = 0;
pnlPokemonInParty.add(btn1, c);
c.gridx = 1;
pnlPokemonInParty.add(btn2, c);
this.add(pnlPokemonInParty);
this.pack();
this.setVisible(true);
}
public JButton gifBtn(String name)
{
final JButton btn = new JButton();
URL url = null;
try {
url = new URL(images.get(name));
} catch (MalformedURLException ex) {
ex.printStackTrace();
}
Icon icon = new ImageIcon(url);
btn.setIcon(icon);
btn.setBackground(new Color(50,50,50,0));
return btn;
}
public static void main(String[] args)
{
GameManager gameManager = new GameManager();
}
}
我可以通过不将 Jbutton 的背景颜色设置为透明来隐藏问题,但这并不能解决问题。
为什么会出现这种情况? 我更担心两个图像位于同一个 JButton 上,但是在查看图像时,还有另一个问题很容易注意到,我真的不知道如何解释......我认为在每个重绘周期中将 gif 的当前帧绘制到 gif 的每一帧的相同图像上,因此您可以看到 gif 的当前帧以及所有先前绘制的帧。如果在每个重绘周期创建一个新的 BufferedImage 并将当前帧绘制到该图像上,我认为这可以解决问题。
发布问题时,建议发布 MRE,如下所示:
import java.awt.Color;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class GameManager extends JFrame{
private final Map <String, String> images = new HashMap<>(2);
GameManager()
{
images.put("Articuno", "https://cdn3.iconfinder.com/data/icons/softwaredemo/PNG/256x256/Box_Green.png");
images.put("Rayquaza", "https://cdn3.iconfinder.com/data/icons/softwaredemo/PNG/256x256/Box_Red.png");
JPanel pnlPokemonInParty = new JPanel(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
JButton btn1 = gifBtn("Articuno");
JButton btn2 = gifBtn("Rayquaza");
c.gridx = 0;
pnlPokemonInParty.add(btn1, c);
c.gridx = 1;
pnlPokemonInParty.add(btn2, c);
this.add(pnlPokemonInParty);
this.pack();
this.setVisible(true);
}
public JButton gifBtn(String name)
{
final JButton btn = new JButton();
URL url = null;
try {
url = new URL(images.get(name));
} catch (MalformedURLException ex) {
ex.printStackTrace();
}
Icon icon = new ImageIcon(url);
btn.setIcon(icon);
btn.setBackground(new Color(50,50,50,0));
return btn;
}
public static void main(String[] args)
{
GameManager gameManager = new GameManager();
}
}
该代码使用公开可用的图像可以正常工作,因此表明本地资源存在问题。
MRE 让帮助变得更加容易
是一个强大的调试工具。很多情况下,在准备的时候,你很可能会发现问题。
btn.setBackground(new Color(50,50,50,0));
尊重此属性取决于外观和感觉,有些人可能会 选择忽略它。
(引自
JComponent#setBackground(Color)
文档。)
编辑2:
覆盖
JButton
的自定义 paintComponent
可以正常工作(透明颜色,其中 alfa 为 0,如 new Color(50,50,50,0)
或任何其他颜色):
class Main extends JFrame{
private final Map <String, String> images = new HashMap<>();
Main()
{
images.put("Articuno", "https://66.media.tumblr.com/d9105814c15295196a3dbe75c32ba1a0/tumblr_oagpklvBGf1scncwdo1_400.gif");
images.put("Rayquaza", "https://play.pokemonshowdown.com/sprites/ani-back-shiny/rayquaza.gif");
images.put("GreenCircle", "https://cdn3.iconfinder.com/data/icons/softwaredemo/PNG/128x128/Circle_Green.png");
images.put("RedBox", "https://cdn3.iconfinder.com/data/icons/softwaredemo/PNG/256x256/Box_Red.png");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
getContentPane().setBackground(Color.WHITE);
this.setLayout(new FlowLayout());
this.add(gifBtn("GreenCircle"));
this.add(gifBtn("RedBox"));
this.add(gifBtn("Articuno"));
this.add(gifBtn("Rayquaza"));
this.pack();
this.setVisible(true);
}
public JButton gifBtn(String name)
{
JButton btn = new CustomButton();
try {
URL url = new URL(images.get(name));
btn.setIcon(new ImageIcon(url));
} catch (MalformedURLException ex) { ex.printStackTrace(); }
return btn;
}
public static void main(String[] args) throws Exception
{
new Main();
}
}
class CustomButton extends JButton{
private final Color bgColor = new Color(255,192,203,0);
public CustomButton() {
//setBorderPainted(false); //optioal
setContentAreaFilled(false);
setOpaque(false);
}
@Override
public void paintComponent(Graphics g){
g.setColor(bgColor);
Rectangle r = g.getClipBounds();
g.fillRect(r.x, r.y, r.width, r.height);
super.paintComponent(g);
}
}
JComponent#setBackground(Color)
文档指出:
JComponent 的直接子类必须重写 PaintComponent 以支持此属性。 尊重这个属性取决于外观和感觉,有些人可能会选择忽略它。
出于某种原因
JButton
没有。