在JFrame中使用坐标平面 [英] Using the coordinate plane in the JFrame

问题描述

//我想学习如何绘制的Java对象。我得到它好，但一旦我得到我无法操纵在屏幕上的图像。我把这些数字是没有意义的形状如何转出。至少对我来说他们不这样做。在代数如果增加在x轴有若干它去的权利，如果增加在y轴有若干它上升。那不是什么发生在这里。谁能给我解释一下这是如何工作？我还是新来的Java，所以更多的解释和详细越好。我试图采取了几个小时了，每天在我的暑假学习java，有时就有点令人沮丧。任何帮助是极大的AP preciated。

//I am trying to learn how to draw objects in java. I'm getting better at it, but once I get an image on the screen I am having trouble manipulating it. The numbers I put in don't make sense to how the shapes are turning out. At least to me they don't. In algebra if you increase a number on the x axis it goes to the right and if you increase a number on the y axis it goes up. Thats not whats happening here. Can anyone explain to me how this works? I'm still new to java, so the more explanation and detail the better. I'm trying to take a couple of hours out a day over my summer to learn java and sometimes it gets a little frustrating. Any help is greatly appreciated.

推荐答案

下面的坐标从左上方启动的屏幕上，只要你增加 X 的价值，你会朝右侧动，但当您增加是的价值，你会移动 DOWNWARDS 。这里是一个小例子程序，为您更好一点理解这一点，只需点击任何地方。

Here the Co-ordinates start from the TOP LEFT SIDE of the screen, as as you increase value of X, you will move towards RIGHT SIDE, though as you increase the value of Y, you will move DOWNWARDS. Here is a small example Program for you to understand this a bit better, simply click on it anywhere.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class DrawingExample
{
    private int x;
    private int y;
    private String text;
    private DrawingBase canvas;

    private void displayGUI()
    {
        JFrame frame = new JFrame("Drawing Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        canvas = new DrawingBase();
        canvas.addMouseListener(new MouseAdapter()
        {
            public void mouseClicked(MouseEvent me)
            {
                text = "X : " + me.getX() + " Y : " + me.getY();
                x = me.getX();
                y = me.getY();
                canvas.setValues(text, x, y);
            }
        }); 

        frame.setContentPane(canvas);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new DrawingExample().displayGUI();
            }
        });
    }
}

class DrawingBase extends JPanel
{
    private String clickedAt = "";
    private int x = 0;
    private int y = 0;

    public void setValues(String text, int x, int y)
    {
        clickedAt = text;
        this.x = x;
        this.y = y;
        repaint();
    }

    public Dimension getPreferredSize()
    {
        return (new Dimension(500, 400));
    }

    public void paintComponent(Graphics g)
    {
        super.paintComponent(g);
        g.drawString(clickedAt, x, y);
    }
}

这篇关于在JFrame中使用坐标平面的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！