Question

我试图制作一个可以让你选择所需图像数量的程序，然后会询问你想要使用的文件的名称。然后它将以适当的方式在屏幕上以网格打印它们。

现在我知道这段代码的很多部分，比如宽度和高度，行和列，以及其他的东西都是错的，我打算在我弄清楚这一点之后修复它们。不管我如何改变它，它都不会让我使用paintComponent。我想把它留在我的主要课堂上，这还有可能吗？很多时候我把它放在一个单独的图形类中，但是引入我对该类的输入是令人恼火的。

import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Image;
import java.util.ArrayList;
import java.util.Scanner;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Core extends JPanel{
    public static void main(String[] args){
        Scanner r = new Scanner(System.in);
        System.out.println("How many selections will you have? 1, 2 or 4? ");
        if(r.next().contains("1") | r.next().contains("2") | r.next().contains("4")){
        String selections = r.next();
        int number = Integer.parseInt(selections);
        ArrayList<String> images = new ArrayList();
        for(int j = 1; j <= number; j++){
            System.out.println("Your options are boo, bae, skinny, bro...");
            System.out.println("Name of image " + j + "? ");
            if(r.next().contains("boo") | r.next().contains("bae") | r.next().contains("skinny") | r.next().contains("bro"))
            images.add(r.next());
            else{
                System.out.println("Im sorry that was an improper input...");
                System.out.println("Next time, remember, you can only input boo, bae, skinny, or bro.");
                r.close();
            }
        }

        JFrame theGUI = new JFrame();
        theGUI.setTitle("Random Images");
        theGUI.setSize(number * 100, number * 100);//ratio of 1:100
        theGUI.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Container pane = theGUI.getContentPane();

        pane.setLayout(new GridLayout(number, number));
        for(int j = 1; j <= number; j++){
            Color backColor = Color.white;
            Image  image = new ImageIcon((images.get(j)) + ".jpg").getImage();
            public paintComponent(Graphics g){//error here(paintComponent cannot be resolved to a variable)(Illegal modifier for 'g')
                super.paintComponent(Graphics g);//and error here (cannot use super)(Graphics cannot be resokved to a variable)

            g.drawImage(image, 0, 0, 100, 100, null);}
            ColorPanel panelz = new ColorPanel(backColor);
            pane.add(panelz);
        }


        theGUI.setVisible(true);
        }//end of the checker for the 1, 2 and 4.

        else {
            System.out.println("I'm sorry that was an improper input.");
            System.out.println("Keep in mind your inputs may only be 1, 2 or 4.");
        }
    }

}

在评论中发布代码的道歉，我是新来的。但是，当我喜欢你说，我为变量声明id做了什么？

public class Core extends JPanel{

    public static Image image;

    public void paintComponent(g){//insert VariableDeclaratorID error
        super.paintComponent(g);

    g.drawImage(image, 0, 0, 100, 100, null);
    }

    public static void main(String[] args){

Answer 1

您正在尝试覆盖方法中的方法。这不仅在Java中是非法的，也不是在Swing中完成绘画的方式。
您尚未提供paintComponent方法的返回类型
调用方法时，您不需要声明参数类型super.paintComponent(Graphics g);，只需将正确类型的对象的实例传递给它，super.paintComponent(g);
不要将基于控制台的输入与GUI输入混合使用。 GUI在事件驱动的环境中运行，这使得它们本质上是非线性的，并且在UI运行时很难从命令行收集用户的信息。

在继续之前，请先看看：

拿这个......

public paintComponent(Graphics g){    error here(paintComponent cannot be resolved to a variable)(Illegal modifier for 'g')
    super.paintComponent(Graphics g);    and error here (cannot use super)(Graphics cannot be resokved to a variable)

g.drawImage(image, 0, 0, 100, 100, null);}

从for-loop开始，将其作为Core班级的方法......

@Override
public void paintComponent(Graphics g) {
    // ^--- Need this...
    super.paintComponent(g);
                      // ^--- Don't need Graphics, just an instance of it...
}

main不是一个类，它是一种方法，一种Core的方法;）

例如......

public class Core extends JPanel{
    public static void main(String[] args){
        //..
        pane.setLayout(new GridLayout(number, number));
        for(int j = 1; j <= number; j++){
            Color backColor = Color.white;
            Image  image = new ImageIcon((images.get(j)) + ".jpg").getImage();
            // This be bad...
            //public paintComponent(Graphics g){//error here(paintComponent cannot be resolved to a variable)(Illegal modifier for 'g')
            //    super.paintComponent(Graphics g);//and error here (cannot use super)(Graphics cannot be resokved to a variable)
            //
            //g.drawImage(image, 0, 0, 100, 100, null);}
            ColorPanel panelz = new ColorPanel(backColor);
            pane.add(panelz);
        }


        theGUI.setVisible(true);
        //...
    }

    // This be better...
    @Override   
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        // Draw the List of images here how ever you want...
    }

}

<强>更新...

好的，如果我理解你的评论，你想要做的是创建一个JPanel的实例，但为每个图像提供它的paintComponent方法的自定义实现...

for(int j = 1; j <= number; j++){
    Color backColor = Color.white;
    final Image  image = new ImageIcon((images.get(j)) + ".jpg").getImage();
 // ^--- This is important
    panel.add(new JPanel() {

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(image.getWidth(), image.getHeight());
        }

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

将一些图像绘制成一个窗格

1 个答案: