如何在paintComponent方法中使用命令参数？
如何在paintComponent方法中使用命令参数？
提问于 2014-11-16 17:27:03
我目前正在尝试创建一个Java程序，该程序根据终端中给定的参数生成图像。例如，如果我在命令行java Draw Image1中得到了参数，我希望为其他命令行绘制图像1等。如何在paintComponent中使用命令参数？下面是我想要做的事情的一个例子：
import javax.swing.*;
import java.awt.*;
public class Draw extends JPanel
{
public Draw()
{
this.setSize(800,800);
JPanel drawing = new JPanel();
this.add(drawing);
this.setVisible(true);
}
protected void paintComponent(Graphics g)
{
if (args[0].equals("Image1")) // won't work
{
super.paintComponent(g);
Image myImage = Toolkit.getDefaultToolkit().getImage("image/myimage.jpg");
g.drawImage(myImage, 0, 0, this);
}
else
{
// draw image 2
}
}
public static void main(String[] args)
{
// create new Jframe
JFrame frame = new JFrame("Draw");
frame.add(new Draw());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500,500);
frame.setVisible(true);
}
}回答 1
Stack Overflow用户
回答已采纳
发布于 2014-11-16 17:29:07
改变这一点：
frame.add(new Draw());对此：
frame.add(new Draw(args));然后让构造函数接受字符串数组参数，并使用它来设置类字段。
public class Draw extends JPanel
{
private String[] params
public Draw(String params)
{
this.params = params;
this.setSize(800,800); // this generally should be avoided
JPanel drawing = new JPanel();
this.add(drawing);
this.setVisible(true);
}
protected void paintComponent(Graphics g)
{
super.paintComponent(g); // this should be out of the if block
if (params != null && params.length > 0 && params[0].equals("Image1")) {
// ..... etc编辑: Andrew是对的，我没有仔细阅读您的代码。在构造函数中读取图像，并在paintCompnent方法中的图像中使用它
例如，
import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
@SuppressWarnings("serial")
public class Draw extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = PREF_W;
private BufferedImage image;
public Draw(String[] params) throws IOException {
if (params != null && params.length > 0) {
image = ImageIO.read(new File(params[0]));
}
// this.setSize(800,800);
JPanel drawing = new JPanel();
drawing.setOpaque(false); // may need this
this.add(drawing);
this.setVisible(true);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (image != null) {
g.drawImage(image, 0, 0, null);
} else {
}
}
@Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
// not sure if you want to size it to the image or not
if (image != null) {
int w = image.getWidth();
int h = image.getHeight();
return new Dimension(w, h);
} else {
return new Dimension(PREF_W, PREF_H);
}
}
public static void main(String[] args) {
// create new Jframe
JFrame frame = new JFrame("Draw");
try {
frame.add(new Draw(args));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// frame.setSize(500,500);
frame.pack();
frame.setVisible(true);
} catch (IOException e) {
e.printStackTrace();
}
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/26959864
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